HOMEWORK ASSIGNMENT

 DNA evidence for blood test
Index for the DNA sample of Group 1
From left to right-
Reveilles blood sample (a)
M. flash shirt(a)
M. flash DNA  (b)
Biker man shirt(c)
Biker man DNA (c)
Ladder (l)
Reveille fur (a)
Results

1. From the fingerprint test, it can be assumed that the culprit could be Maroon Flash.

2. The presumptive blood evidence indicates the presence of human blood on Reveilles fur collar,  
the Biker mans shirt and Maroon Flashs shirt.

3. The DNA fingerprint results from hair and blood sample definitely incriminates Maroon Flash as the bands in the gel or the distance traveled by the DNA fragments obtained from Maroon Flash exactly match those from Reveille.

Inference
From these results it can be concluded that there is sufficient evidence to focus on one subject for further investigation. The results of the DNA fingerprint test clinch the evidence incriminating Maroon Flash as the DNA from his shirt match those exactly of Reveille. Hence, the evidence indicates that one of he is lying about hitting Reveille.

The three variables that influence the distance that DNA fragments move through an electrophoresis gel under the influence of an electric motive force are
The mass of the DNA fragments- the heavier or larger the fragments, the lesser the distance moved.
The porosity of the gel or inversely, the concentration of media used which would not allow bigger molecules to cover more distance through its mesh network.

The third factor is the e.m.f. charge and the time for which the current has been allowed to pass through the gel electrophoresis setup.

Forensic experts compare crime scene evidence to reference materials or samples obtained from suspects is because the DNA fingerprinting technique has been developed to such an extent that it can be used to distinguish between two individuals of the same species. The charge to mass ratio of all species is the same (Z) but the bands obtained by passing e.m.f. through a gel containing DNA samples from victims or potential crime scenes, gives an uncanny rate of success in implicating or exonerating a suspect. Variability in Short Tandem Repeat sequences can be used to distinguish one DNA profile from another. Hence, in recent times DNA fingerprint evidence has gained immense popularity in not only solving criminal cases but also unresolved paternity cases.

Muscular System Histology and Physiology

Which of the following is NOT a function of skeletal muscle

body movement
maintenance of posture
respiration
constriction of organs
production of heat

Which of the following is true

Skeletal muscle is capable of spontaneous contraction.
Smooth muscle is found in the walls of hollow organs.
Cardiac muscle cells have multiple nuclei.
Smooth muscle cells are long and cylindrical.
There is a small amount of smooth muscle in the heart.

Which type of muscle tissue has cells that branch

skeletal muscle
smooth muscle
cardiac muscle
both skeletal and cardiac muscle
both cardiac and smooth muscle

Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the

number of muscle fibers.
size of muscle fibers.
number of striations.
number of nuclei within the muscle fibers.
number of muscle cells.

Actin myofilaments

resemble bundles of minute golf clubs.
contain both myosin and tropomyosin.
are held in place by the M line.
contain strands of fibrous actin.
are the thickest proteins in muscle.

When an action potential reaches the presynaptic terminal,

calcium ions diffuse into the presynaptic terminal through voltage-gated ion channels.
acetylcholine moves into the presynaptic terminal.
a local potential is generated in the presynaptic terminal.
ligand-gated ion channels in the presynaptic terminal are opened.
nothing else happens.

In excitation-contraction coupling,

calcium ions must bind with myosin to expose active sites on actin.
myosin heads bind to exposed active sites on actin.
cross-bridges form between myosin heads and calcium ions.
movement of the troponin-tropomyosin complex causes actin myofilaments to slide.
ATP binds to actin myofilaments.

Which of the following helps explain the increased tension seen in multiple wave summation

increased motor unit recruitment
increased concentration of calcium ions around the myofibrils
exposure of more active sites on myosin myofilaments
the breakdown of elastic elements in the cell
decreased stimulus frequency

An isotonic contraction is described as

action potential frequency is high enough that no relaxation of muscle fibers occurs.
a muscle produces constant tension during contraction.
a muscle produces an increasing tension during contraction.
a muscle produces increasing tension as it shortens.
a muscle produces tension, but the length of the muscle is increasing.

Which type of respiration occurs in the mitochondria

anaerobic respiration
aerobic respiration
both anaerobic and aerobic respiration

Muscular System Gross Anatomy
The sternocleidomastoid muscle extends from the mastoid process of the temporal bone to the sternum and medial clavicle. When both sternocleidomastoid muscles contract, the head is flexed. The end of the muscle that connects to the sternum is the

origin.
belly.
body.
insertion.
fixator.

Which of the following represents a class I lever system

crossing your legs
hyperextension of the head
standing on your tiptoes
flexion of the elbow to elevate the hand
lifting weight with your arm

In order to stabilize the hyoid so that the larynx can be elevated in swallowing, the _____ muscle group is used.

Pterygoid
Infrahyoid
Auricularis
Suprahyoid
hyoglossus

If abdominal muscles are contracted while the vertebral column is fixed this will aid in

vomiting.
childbirth.
urination.
defecation.
All of these choices are correct.

Which muscle will depress the scapula or elevate the ribs

levator scapulae
serratus anterior
pectoralis minor
subclavius
rhomboideus major

Which of the following muscles extends the forearm and has its insertion on the ulna

Deltoid
biceps brachii
triceps brachii
brachialis
coracobrachialis

The gluteus maximus

does most of the work in sit-ups.
accounts for a sprinters stance.
allows one to sit cross-legged.
is used in the knee-jerk reflex.
is a common site for injections.

Label muscle A on the diagram.

orbicularis oculi
temporalis
trapezius
sternocleidomastoid
masseter

Label muscle A on the diagram.

linea alba
serratus anterior
rectus abdominis
external oblique
internal oblique

What does A represent

Coracobrachialis
Deltoid
pectoralis major
biceps brachii
serratus anterior

Dolphin Sonar

Abstract
This paper tackles in detail the mechanism of the dolphin sonar  the transmission, reception and signal interpretation process. It also discusses the nature of echolocation signals of dolphins that can whistle and of those which cannot. Moreover, the paper gives some insight on how different bat echolocation is from that of the dolphin, as well as the differences between the inner ear structures of humans and dolphins and its significance.

Introduction
It is said that even in the clearest tropical water, one cannot see farther than a few hundred feet (Jewell, 2005). Even in some bodies of water, visibility does not go beyond 30 feet. This simple fact means that whales, dolphins, and porpoises, collectively called cetaceans, cannot rely much on their vision for communication or foraging. Somehow the only way they can explore the sea is through the use of sound.

Dolphins use echolocation, or dolphin sonar, for navigation and for the accurate tracking, detection and localization of prey. What the dolphins have is similar to other biological sonar systems like those of bats and sperm whales. The dolphin sonar consists of a transmitter, a receiver and a processor. This system is efficient in targeting animals as small as a sardine which is but 9-18 cm long and even at distances of zero to over 100 meters (Mo, 2007). It is believed that the dolphin sonar can even outperform man-made sonar systems (Dobbins, 2007) because unlike man-made sonar systems, a dolphin sonar system can work efficiently in shallow waters and produce signals that are not confounded by water turbulence, increased sound wave reverberations, and suspended sediment (Mo, 2007).

A better understanding therefore of the dolphin sonar can lead to the development of better and improved man-made sonar systems. A clear and thorough understanding of even just the basic principles that govern the mechanism of dolphin sonar is essential to understanding not only how animals react to their environment but also how man-made sonar systems can be improved through this knowledge. Most of all, such an understanding can lead us to think of ways on how to apply such principles in the fields of human psychology and brain physiology.

The Sonar
SONAR stands for Sound Navigation Ranging. It is a technology that involves the use and interpretation of sounds in order to detect the location of something underwater. There are two reasons that somehow make the sonar an ideal type of equipment first, bodies of water are often deep and its murkiness impedes visibility, and second, sound travels more quickly in water than in air (McGrath, 2010).

The sonar is an apparatus particularly used by certain ships and submarines for industrial exploration, that is, the detection of oil and gas, as well as for seismic exploration, which refers to the search for fossil fuel sources on the ocean floor. One particular type of sonar, called the military sonar, is normally used for military exercises and for detection of vessels, mines and torpedoes (Sound and Sonar Issues, 2010).

Sonar operates by producing sound to be able to detect objects from afar especially underwater. Passive sonar involves listening in order to locate and study marine life as well as threats in the ocean. On the other hand, active sonar involves both transmission and reception of sound waves, that is, sending a sound pulse and measures how long the sound will be reflected back (Nicholson, 2010). The dolphin sonar is an example of active sonar.

The Dolphin
Dolphins are marine mammals that belong to the family Delphinidae of the order Cetacea and are closely related to whales and porpoises. With almost 40 species in 17 genera, dolphins are found worldwide and are said to have evolved about 10 million years ago but have somehow retained a primitive mammalian brain characteristic of that of its ancestors 50 million years ago during the Eocene epoch (Bekman, 2009).

Although dolphin intelligence has not been accurately measured to date, this particular cetacean has several otherwise intelligent characteristics a primitive yet highly elaborate archetypal brain, complex vocalizations that somehow prove the ability to communicate with members of their species, and a sonar system that works hand in hand with their vision (Bekman, 2009). There have also been claims that dolphins can alter the mental make-up and overall physical health of autistic and disabled children as well as patients with diseases that include even cerebral palsy and mental retardation (Healing through dolphins, 2009). Moreover, there is considerable scientific proof that the reasons for these sophisticated features of the dolphin are due to particular characteristics of its brain, particularly the neocortex.

Morgane and Glezer theorized that the neocortex of the cetacean brain has retained during evolution the capability to adapt of modify neuronal types to whatever form is most opportune for its specific function. The implication is that the neocortex is not phylogenetically preordained and it is this very feature that enables animals to continually modify their behavior in order to adapt themselves to novel events in their environment (as cited in Thomas  Kastelein, 1990). These findings somehow imply that dolphins may have retained the otherwise sophisticated abilities of the ancestral mammalian brain to adopt to environmental changes hence their elaborate sonar systems and other specialized characteristics.

Evolution of the Dolphin Brain and Sonar
Cetaceans are believed to have descended back to the sea around 50-70 million years ago. They may have adapted themselves to the new conditions of their aquatic environment but they certainly appear to have preserved unique features of the original structure of the brain of primitive mammals extant during that period in a much greater measure compared to land animals. One more factor in the advancement of the cetacean brain is that the new aquatic environment was conducive to develop novel and specific features of brain adaptation of which land mammals were incapable. Morgane and Glezer, in their studies of the cetacean brain for over 20 years, found out that the cortex of the dolphin has remained unchanged for the past 50-70 million years. The cetacean brain, with its extremely vigorous quantitative expansion of neocortex, may then perhaps represent a prototypic mammalian brain which is considered to be the most ancient among present-day mammals. Morgane and Glezer also claim that such a primitive yet highly more specialized neocortex among cetaceans compared to land mammals may have existed for one reason the assumption that the return to water somehow retained such primitive brain characteristics. The return of the cetaceans to water took place before land animals developed pyramidal cells in their neocortex, which was the beginning of the highest degree of sensory and motor cortical specialization in land mammals (as cited in Thomas  Kastelein, 1990).

According to Professor David Lindberg, an evolutionary biologist at University of California-Berkeley and co-author of a study on the evolution of echolocation among toothed whales, as to the evolution of the dolphin sonar, scientists believe that just like bats which developed sonar while chasing flying insects, the cetaceans developed sonar to chase squid at night. Lindberg added that as soon as the first cetaceans transferred to the ocean, they found this incredibly rich source of food surfacing around them every night and bumping into them. Thus, in order to adapt to this otherwise difficult yet essential lifestyle, the biosonar system evolved   (Whale and dolphin, 2007).

Mechanism of the Dolphin Sonar
Dolphins use a sensory sonar system for locating things in their environment and for communication. The basic mechanism is that dolphins release a concentrated beam of sound waves in the form of clicking sounds and then listen to the corresponding echo. From this, they are able to determine certain key aspects of an object that include the size, shape, distance, speed, direction as well as internal structure depending on the object (Jewell, 2005).

The dolphin sonar system is actually made up of three subsystems transmission, reception, and decision makingsignal processing subsystems. The transmission subsystem involves the mechanism of producing sounds, acoustic propagation coming from inside the head of the dolphin out into the water, and the nature of the signals traveling in the surrounding environment. Next, the receiving subsystem involves the dolphins auditory system. Lastly, the signal processing or decision making subsystem consists of the ability of the dolphins auditory system to extract useful information from the echoes as well as the cognitive capabilities of the animal. Optimal use of acoustical information usually requires an auditory system that can cover a wide frequency range (Au et al., 2000).

Basic Mechanism of the Transmission of Sound Waves. Mo (2007) presents a step-by-step process to illustrate the mechanism of a dolphin sonar first, bursts of clicks of varying frequencies are produced in a series of air sacs contained in the nasal cavities. Second, the valves called bursae or monkey lips, or what Au et al. (2000) refers to as the monkey lips-dorsal bursae complex, open into the blowhole passage. Third, an air-filled cavity emits the dolphins echolocation signals into water, causing a mismatch in the propagation of the sound waves from air to water. Fourth, such an imbalance is overcome by the melon, which is a large deposit of fatty tissues extending into the nasal sac muscles. The melon acts to slow down sound waves as they are emitted from the nasal air sacs in order to make the transfer of sound waves from air to water smoother.

Dobbins (2007) states that it is now a widely accepted fact that the lower jaw is a major component of the echo-receptor in dolphins. The lower jaw and the surrounding structures is the part of the dolphins head through which many of the acoustic signals to which dolphins are sensitive are brought to the middle and inner ear.

In addition to the lower jaw and the parts that originally facilitate the transmission of the sound waves, the dolphins teeth also play a major role in the mechanism of the dolphin sonar and the role is that of a sonar array. Dolphins, first of all, are homodonts, or animals with uniformly-shaped teeth evenly-spaced along the jaw in two straight lines. The teeth actually serve as resonant pressure transducers, which means that they act as an array of receivers which produce vibrations according to changes in pressure caused by sound waves while they travel through the water. Moreover, there is some experimental evidence pointing to the role of dolphins teeth in receiving acoustic signals. The teeth of dolphins have actually been found to resonate at frequencies ranging from 115,000-135,000 Hz in response to sounds. However, this theory on the role of the dolphins teeth in echolocation was opposed by Whitlow Au, the chief scientist at Marine Mammal Research Program of the Hawaii Institute of Marine Biology as chief scientist, who contended that several dolphins who have lost their teeth were still able to activate their sonar systems (Dobbins, 2007).

Characteristics of Echolocation Signals. There are basically two kinds of dolphins the ones capable of whistling and the ones that cannot whistle (Au et al., 2000).

Dolphins that are capable of producing whistling signals include the bottlenose dolphin (Tursiops sp.), Pacific whitesided dolphin (Lagenorhynchus obliguidens), Amazon River dolphin (Inia geoffrensis), Atlantic spotted dolphin (Stenella  frontalis), Rissos dolphin (Grampus griseus), Pacific spotted dolphin (Stenella attenuate), rough tooth dolphin (Steno bredanensis), spinner dolphin (Stenella longirostris), and Chinese river dolphin (Lipotes vexillifer). However, most of what is known about dolphin sonar systems was obtained from the bottlenose dolphin as well as two other cetaceans beluga whale and false killer whale. Peak frequencies usually reach between 120,000 and 130,000 Hz (Au et al., 2000).

The second type of echolocation signals are produced by dolphins and porpoises that gave no evidence of being able to emit any whistle signals. The production of their sounds is restricted to high frequency, low intensity click signals. These species include Commersons dolphin (Cephalorhynchus commersonii) and the Hectors dolphin (Cephalorhynchus hectori) among the dolphins. The three other species that have the same characteristics are porpoises. Compared to that of whistling signals, the duration of click signals is much longer. The signals also exhibit many oscillations and the spectra are much narrower. The peak frequencies reach up to 140,000 Hz (Au et al., 2000).

Comparison with Bat Echolocation. Bats are the first animals found to possess the ability of echolocation. Both bats and dolphins possess biological sonar systems. However, the tonal airborne signals of bats are normally much longer in duration compared to the click-like calls of dolphins. The shorter calls of the dolphin somehow enable them to produce a good temporal resolution in water since water is a type of medium where the speed of sound is five times as fast as in air (Troitino, 2010).

Another difference between bats and dolphins when it comes to their sonar systems is that dolphins possess a greater control of its sonar system and can alter the sonar transmitter, whereas bats can alter the gain of the sonar receiver. This difference somehow is of advantage to dolphins because their middle ear muscles are stiffer and denser than in bats which make the latter less adaptable (Troitino, 2010).

One more difference is in the perception of acoustic images. Those perceived by dolphins are most likely not comparable with those perceived by bats. The reason for such difference is the greater density of water and its relatively lower compressibility compared to air thus accounting for greater acoustic impedance in water. It is believed that dolphins can use this difference to their advantage by detecting their prey with it even if the prey is under sediment (Troitino, 2010).

One last difference between bats and dolphins is that the latter produce their echolocating clicks from the inside of the phonic lips located in the nasal passages, specifically in a series of air sacs (Moh, 2007), transmit this sound through a special structure called a melon, or a sac-like pouch of fatty tissues located on the forehead, and receive the echoes through their lower jaws (Troitino, 2010).
Dolphin Sonar Frequency Range. A majority of marine dolphins have a large repertoire of sounds including two general types of pulsed sounds, the first of which is used for its sonar or echolocation ability and the second type is emitted when the animal is in a state of emotion. Aside from the echolocating clicks, dolphins also emit whistles and chirps which are in fact pure tone sounds. The whistles and chirps have varying loudness and duration (Erber, 1996).

When it comes to frequency of the dolphin sonar, various studies have found out that the range of the low end is from 100 Hz to 8,000 Hz while the higher end of the range shows a variation of 120,000 Hz up to 200,000 Hz. Mo (2007) specifies an average dolphin sonar frequency of a maximum of 160,000 Hz. One factor that accounts for the differences is the relative accuracy and sensitivity of the tools used to measure the frequencies through the years. The frequency ranges are also still subject to greater scrutiny since there is a need for scientists to consider the size, gender and age of the dolphins, the location of the measurements, the time of the year the measuring is done, plus many other factors that may have caused the present discrepancies in the current data in the first place (Erber, 1996).

High frequency sonar systems for dolphins may share the same advantage as their mechanical counterparts. The use of high frequency sonar systems such as 1.8 and 2.4 MHz is said to provide a sufficient resolution for target recognition and identification (Wilcox  Fletcher, 2004).

Basic Mechanism of the Reception of Echoes. Au (1993) states that the receiving system of a dolphins sonar is its auditory system which consists of the outer, middle and inner ears. Even until now, it is not exactly clear how and where exactly sound is conducted into the middle and inner ears of the dolphin considering the narrow structure and fibrous structure of the external meatus. These two characteristics make the outer ear hardly capable of being an acoustic pathway to the middle and inner ears. Although some scientists argue that the external meatus is indeed the primary pathway for sound transmission, there is an alternate theory suggesting that the external meatus is nonfunctional and that it is through the thinned posterior portion of the mandible that the sound enters the dolphins head. The sound is then transmitted across a fat-filled canal to the tympano-periotic bone where the middle and inner ears are located. At this point, the sound is basically interpreted in the same way as in any other mammalian auditory system.

However, Wever et al. made an estimate of the ganglion cell population associated with the cochlear hair cells in the inner ear. They were able to estimate a population of around 70,000 for the Lagenorhynchus species and 95,000 for Tursiops. These numbers were found to be considerably greater than those found in man which number only 30,500. The ratios of the number of ganglion cells to hair cells in the two previously mentioned species of dolphin are four and five times respectively, surpassing the human ratio of only two times. Wever et al. said that this high ratio of ganglion cells to hair cells in dolphins may explain why these animals are capable of interpreting high frequency acoustic information and finer details of cochlear events in the more highly activated centers of their auditory nervous system (as cited in Au, 1993).

Actually, the dolphin sonar enables the dolphin to perceive objects around it in a much more complex way than it seems since the information available from the dolphin sonar may at times include things that cannot be seen with the naked eye. Depending on the object, sound waves can penetrate the surface before bouncing off thus giving feedback and information about the internal structure of the object (Jewell, 2005).

The moment an echolocation click hits a particular target such as a fish, a proportion of the click bounces back as an echo and is physically detected by the dolphin. The dolphin can determine how far away the fish is from the moment the echolocation click was sent out to the time it returns. The dolphin, however, has to make several more clicks and hear more echoes before it can precisely determine how fast and in what direction the fish is moving. The dolphin sonar can detect an object with the length of as little as 2.5 cm from an unusually long distance of 72 meters, while Moh (2007) claims only an object 9-18 cm in length but at a distance of up to 100 meters. Nevertheless, what is important is that the closer the dolphin is to its target, the more clicks it sends out and the more echoes bounce back (Jewell, 2005).

Conclusion
Dolphins are certainly not only animals one enjoys watching during shows. The animal has, through the millennia, evolved into a species that possesses not only healing abilities but well-developed sonar systems. The dolphin sonar is indeed one of the most sophisticated characteristics of the aquatic mammal. This characteristic basically evolved from the hunting habits of the aquatic ancestors of cetaceans while there are claims that the brain of the dolphin, particularly the neocortex, has remained unchanged for millions of years thus accounting for a sharply primitive way of dealing with their environment. However, no matter what the evolutionary origin of the dolphin sonar is, this specialized mechanism currently involves an extremely complicated process of transmission and reception of sounds, followed by signal interpretation. Furthermore, recent studies into the nature, origin and significance of the dolphin sonar are leading to more and more questions on the nature and inherent intelligence of cetaceans and of what significance it particularly has on human life and psychology.

Biodiversity The Jelly Fish Case

Earths biodiversity includes variety of organisms that made our world really colorful and blissful to live on. Among these rich biodiversity are the marine organisms living underwater. In order to know more about a particular marine organism-how they really look like and how they can be of great importance to our environment, I visited the Audubon Aquarium of the Americas in New Orleans, Louisiana. At the Aquarium, I am very amazed to the different sea creatures that were living and breathing as if they were in their natural habitat.

With the intention of relating what I learned in the class, I focused my attention to a particular type of sea creature-the jellyfish. I eventually knew the specific type of jellyfish I am observing. I actually observed three different jellyfish comb jellies, Atlantic moon jellyfish and the Northern sea nettle.
All of the three jellyfish can be praised for their colorful appearance or transparent look with colorful pigmentation and their gradual slow motion in the water. They appeared so intricate but undeniably beautiful. The variation in number of tentacles and the position of the mouth of each type of jellyfish was also observed in the aquarium. For example, the comb jellies appear to have two tentacles with eight comb rows which can actually be seen in the water. On the other hand, the moon jellyfish can be distinguishable due to its unique spots and streaks.

Comb Jellies
Comb jellies is a small phylum of marine animals called Ctenophora which contains about 100-150 species. Having the ability to produce blue and green light, Ctenophora appears to be among the beautiful species undersea. In comparison with the cnidarians, they also continue to exist without hard skeletal parts and teeth.

Under the Domain Eukaryota, Kingdom,Animalia, and Subkingdom Eumetazoa, Ctenophoras most undeniable body feature is its comb rows. Highly observable, comb rows follow a wave pattern that moves from the aboral   to the oral end. The movement of a comb prompts the next comb to make its own stroke, thus, making a series of strokes that lead to the formation of the wave-like movement of the comb jellies. Unlike the cnidarian which exhibits a stop-and-go motion, ctenophora follow a smooth motion (Campbell, Neil et al., p. 54)

Nearly all the species of comb jellies favor living in warmer water and in tropical areas. Almost all ctenophora live deep down the sea or found around the poles. Some species also reach up to a depth of 2000 to 3000 meters.

Body Characteristics and Features
A sense organ present at the end opposite the mouth is one of the key features of the ctenophora. It holds a statolith that dictates the orientation of the comb jelly. Like cnidarians, it is at its tissue level of organization with its body exterior wrapped with thin ectoderm. This ectoderm enters the mouth and lines the pharynx. In digestion, the ectoderm serves as the agent of the extracellular digestion occurring in the stomach or stomodaeum.

Ctenophores body is consists of Epidermis, Gastrodermis and Mesoglea which is actually layers of cells. The eight sets of cilia present in its body is use by the organisms to swim and to maintain its original water orientation. They are also considered carnivorous since the classes of Ctenophore, Tentaculata and Nuda both catch fish or other creatures in the sea and feeds same ctenophores exclusively. The comb jellies that I observed possessed two main tentacles with sub-tentacles on its side. This proves that the ctenophore that I have watched is the Tantaculata class. Nuda is the other class of Ctenophore which has very large mouth present in their bell-shaped bodies (Campbell, Neil et al., p.56). This class can eat organisms more than half their size and contains half of the total number of Ctenophores species.

Distinct from Cnidarians, ctenophores have no polyp phase. Almost all ctenophores are hermaphrodites (possesses both the male and female reproductive organ) which in turn produces both sperm and egg cells at the same time. The gonads release the egg and sperm cells in the water through the mouth. External fertilization happens to the egg which in turn develops it to a tiny larva. This larva develops cydippid-like paired tentacles which lessen its number through the course of the life span.

Atlantic Moon Jellyfish
Atlantic moon jellyfish is a specific kind of moon jellyfish that can be found in the Atlantic Ocean. Moon jellyfish scientifically known as Aurelia Aurita is a Cnidarian species under the Ulmaridae Family and Genus Aurelia. The common name moon jelly can be accounted to the moon shaped-gonads at the center of the bell. They can be mostly found in warm and tropical waters near coastlines- withstanding temperatures as low as 6 degree Celsius and as high as 31 degree Celsius. Locally found in Virginias water, they can also be found in many oceans in the world. Moon jellyfish are also present in the Pacific Ocean- from Alaska to Southern California (Coleman, N., p. 69)

Known for its fine and beautiful coloration, moon jellyfish sizes from 5 up to 40 cm in diameter. How they react in the environment depends on external conditions like availability of food. Also observable in the moon jellyfish is its four violet or pink crescent shaped gonads located in its underside. I can also recognize the thickness of the bell of the moon jellyfish in the middle which tends to appear thinner across its edges. The limitation on its movement only allows them to be near the surface of the water. Upon its stay near the surface of the water, its tentacles spread throughout the area, thus, maintaining the largest possible area for the catchment of food.

As we learned in our discussions in the class, Cnidarians have two main stages in life the polyp stage and the medusa stage. Like all cnidarians, moon jellyfish also follow the same life cycle. Aurelia auritas polyp stage or asexual reproduction can be described as a mature polyp reproduce through budding forming. This process develops and in time produces ephyra or small medusae through budding. Upon the maturity of the said medusae, it reproduces sexually allowing a zygote to be formed out of the egg and sperm cells. The next stage will be planula (larva) which in turn leaves the adult medusae.

Considered as carnivorous, moon jellys primary foods include small planknton organisms like crustaceans, nematodes, copepods, protozoans and diatoms. They also eat small ctenophores and hydromedusae. The sting cells present in their bodies prevent the prey from being active allowing the moon jelly to entangle them in mucus. Moreover, the food is passed through the mouth, along the eight canals inside the body. This brings the food directly to the stomach where it is digested by the enzymes.  

Northern Sea Nettle
The northern sea nettle also known as Japanese sea nettle (Chrysaora melanaster) is a species of jellyfish local to eastern Pacific Ocean. Sometimes referred to as Pacific Sea nettle, northern sea nettle is a cnidarian under the class Scypozoa and Pelagiidae family. Common near surface water, northern sea nettle have a bell ranging from 25-30 cm in size and possesses long tentacles which ranges from 3-6 meters. Unlike other cnidarians, the northern sea nettle has no respiratory organs.

As also observed in the aquarium, the northern sea nettle is transparent and contains red-brown stripes and white dots. The sting present in the body is rated from moderate to severe. Causing discomfort and irritation to any organism, the sea nettles sting cannot cause human death.

Chrysaora melanaster as a carnivorous organism uses its mouth as the main hole for digestion. Located at the center of one end of the body, the mouth contains a gastrovascular cavity that is chiefly used for digestion. Northern sea nettle immobilizes their prey through the use of their stinging tentacles.  The common prey ranges from ctenophores, jellies, and zooplankton.

Jellyfish like every other organism gives our environment the benefit of balancing the life underwater. Aside from that, it gave the underwater the colorful place for exploration that in turn will make us appreciate the blessings our Creator gave us.

THE POTENTIAL IMPACTS TO HUMAN HEALTH FROM SPORES OF FUNGI FOUND IN AIR OVER THE SIDNEY BASIN

Introduction
(Levetin, 1995)Fungi are eukaryotic organisms that belong to kingdom distant from plants and animals. Fungi include inconspicuous yeasts, moulds and mildews, as well as large mushrooms, puffballs and bracket fungi. Structurally fungi exist in single cells such as yeasts or thread like hyphae. Fungi normally reproduce through the formation of spores that may result from sexual and asexual reproduction. Sexual spores are result of genetic recombination and follow karyogamy where as asexual spores result from mitosis. Spores contain one to many cells and differ greatly in size, shape, color, and method of formation. Spores may be formed from the fragmentation of undifferentiated hyphae elements or highly specialized hyphal branches that may be contained within sporocraps or fruiting bodies. Mushrooms,  puffballs.

Brackets and morels are well known example these specialized sporocraps. Fungal spores germinate to produce hyphae, which grow and branch within the substrate, typically producing a colony that eventually forms a new generation of spores. Exposure to spores can cause human disease through well defined mechanism. Concerns about spores exposure and its effect are so common that all healthcare providers particularly allergists and immunologists have frequently faced issues regarding these real and asserted spore related illness.  The types of fungi and their abundance in an area depend on the availability of nutrients, water and temperature. We are aware that airborne pollen has well known and well defined seasons, fungal spores can be present virtually year round in many areas of the world. Atmospheric prevalence patterns of the dry air spora, especially those of Rhizopus , Alternaria and Cladosporium are very well known. Rhizopus is genus of moulds that includes cosmolitian filamentous fungi found in soil, decaying fruits, vegetables, animal faeces and old bread.  Rhizopus affects our body by attacking the immune system of our body and causing allergies to your body.Cladosporium is the most abundant genus identified from atmospheric sampling. Although spores can be present year
round but the highest overall concentrations often occur in summer and early fall in temperature areas. The fungi are well known allergen sources Fungus exposure is most commonly associated with hay fever and asthma but also has been implicated in hypersensitivity pneumonitis.(Wilkins,2005)

Alternaria is another class of spore forming fungi found in air and soil they are also common allergens in humans they usually cause hay fever or hypersensitivity reactions that lead to asthama. Many fungal spores contain allergens that may cause one or more of the allergic disease. Note that unlike infectious agents spores may not have to be viable to retain allergenic properties. Hence it is important to know the concentration and composition of the total air spore including non culturable spores and allergen containing fragments, which require immunochemical methods for detection.

Methods
(Halleren et.al 1991)Pollen counts Daily count for moulds Alternaria spp, grass tree and weed and herb pollen were monitored. Airborne pollen grains and moulds should be trapped on Melinex tape coated with adhesive mounted on a rotating drum driven by mechanical clock onto which air should be drawn at 10 liters per minute, by the means of an electrically powered vacuum pump. The 24 hours portions of exposed tape should be mounted on individual  labeled and dated glass slides stained with 2  Saffranin in glycerol jelly and counted by scanning three 48 mm runs then by using high power light microscopy and multiplying the total number by53 to enable the count to be expressed in grains per cubic meter

Pollen identification Reference slides of pollen should be collected from identified plants should be prepared over several years and validate by number of botanists enabling many air borne
pollen to be identified and classified into family or genus and some to species level. Reference slides of pollen from named native flora growing in Mount Annan Botanic gardens

Discussion
(Bass and Morgan 1997)Sydney is the largest city in Australia. There has been no published pollen calendar for Sydney virons since 1941. The present quantitative study has been monitored using Burkard 7 day volumetric spore trap since August 1992.The site has been choosen because of the high prevalence of asthama and the high rate of childhood asthama. The spore trap is sited on the boundary of farm lands to the south developed commercial and housing areas to the north east and north west.in Sydney the prevailing winds are mainly north easterly to south easterly between November and march and south westerly between April and October.the climate of Sydney is subtropical with the mean daily temperature ranging from 22.9 in janury to 12.6 in July. A seasonal pattern of Alternaria sporulation, similar to that of southwest Sydney was observed in Melbourne. According to the statistical analysis Alternaria spore counts in south west Sydney are significantly higher and last longer. In Sidney highest is in the month of November. In south western Sidney where most rain falls during spring and summer between September and January. The influence of sea breeze increases humidity which reduces Alternaria sporulation.

The spore trap in south western Sydney is 30 kilometers from the coast with little sea breeze and on the edge of farming land.(Bass and Morgan,1997) It is likely that not only lower humidity but also local farming practices would assist sporulation. It is therefore necessary when comparing spore counts in different location to be aware of local topography. The data between January 1993 and December 1995 presented in this paper suggests that there is an association between Alternaria spore release and grass pollen release, both of which peak in November. In 1994 when rain fall in Campbell town was low so the total grass pollen count was also low, the total Alternaria count was high .In contrast in 1995 when rainfall increased the total pollen count increased but the Alternaria spore count decreased. The relationship of both grass pollen and Alternaria spore release is dependent upon humidity and rainfall with hot dry days promoting both spore and pollen release. Alternaria is dry where sporulation decreases in rain and increases in dry whether. In the Tucson study peak deposition of Alternaria spores was associated with increasing temperature and decreasing relative humidity. There is a distinct seasonal pattern with Alternaria spore numbers being low in winter and increase in in late spring and early summer, with biomodal peak in November- December, the season of highest rainfall in Sydney and a lower bimodal peak in February   March. The increases could be related to the maturing and sense cense of tree foliage as well as grass and to some extent local crops. Statistical seasonal pattern have demonstrated a negative correlation with rainfall and highly significant correlation with average temperature. Hence it was found that there is a linear relationship between cumulative spore counts and cumulative temperature. Whereas Alternaria spore counts using Burked spore trap sited in a cotton field averaged a background level of 70 spores m3 in April one month before harvesting commenced. The study demonstrated that clouds of Alternaria spores travel some distance and that communities living near cotton fields would be exposed to continue levels of Alternaria round the year. As there is a wide variation of pollen numbers from season to season and variation between start and finish of pollination of many flowering plants only pollen calendar is useful in showing a seasonal pattern. Australia being the driest island continent in the world this variability of pollination is linked to rainfall which proceeds the growing period. This analysis showed that pollen counts totally depends on climatic
conditions.

Result
A large proportion of the population in Sydney lives 30 kilometers inland from coast. This calendar shows seasonal pattern of the flowering tree grass and weed pollen is appropriate to the environment and will help in the diagnosis and treatment of seasonal rhinoconjunctivitis from pollen  asthama .As Alternaria is a risk factor for asthama and a risk factor for sudden respiratory arrest, Alternaria spore counts should be performed routinely at the same time as pollen monitoring.

Reproduction and Embryo Development

The desire to procreate is a basic human drive. DNA plays a role in making the urge for procreation universal. DNA is a molecule that carries genes in a tiny, winded staircase. It is responsible for issuing chemical instructions that make up the body. DNA has the ability to copy itself, in two ways. The first is cloning, in which exact replicas of DNA strands are created. This method is used by bacterium. The second and more advantageous method, sex, is used by majority of the organisms on this planet. It facilitates variety and ensures survival of species.
   
Human body is made of cells. Every cell carries 46 chromosomes, 23 from the mother and the remaining 23 from the father. Genes are carried on long strands called chromosomes. Most cells have two versions of every gene. In sexual reproduction, two individuals contribute DNA, which is placed in sperms and eggs by most species. Sperms and eggs are produced through a process called meiosis wherein a pair of chromosomes replicates, embraces each other and exchanges genetic information. Then the cell divides gradually creating a sperm or egg cell with only half the number of   chromosomes. Every chromosome in the newly created cell contains a new gene combination.

In men, sperms are generated on a daily basis since puberty. However, a woman creates eggs as a fetus. It produces several million eggs in two months, which die with age. Every month, an immature egg nurtures with aid from helpers. The fully grown egg along with its helpers is ejected out of the ovary into the open end of Fallopian tube and then to the uterus, which pulls the egg inside. During intercourse, millions of sperms are released into a fluid from several glands in the male. The fluid passes through a 15-inch tube, followed by the abdomen and is ejected into the vagina through the penis. On entering the vagina, the sperms face acidic conditions which must be escaped to avoid death. Through their journey, womans body and the egg itself control the actions of sperms. To fertilize an egg, a sperm must pass though the cervix past the mucus protective layer, enter the uterus, pass through the chaperones surrounding the egg and break through the eggs protein shield called zona. If the proteins on the eggs surface match those on the sperm cap, the sperm loses its outer coating and releases powerful enzymes creating a hole in the zona. The membranes of the sperm and egg fuse together.

The sperm contents are then pulled into the egg. To create a viable embryo from fertilization, the zona locks out other sperms. The egg and sperm release their 23 chromosomes, which embrace each other followed by cell division. The bundle of cells within the zona is called a blastocyst. It breaks out of zona on the sixth day and releases chemicals to prevent attack from the mothers immune system. For food, it reaches the uterine lining and buries itself into the uterus. Next, it develops a placenta, containing villi on its underside that retrieve oxygen and food from the mothers blood. They are transferred to the fetus, two-month old embryo, through the umbilical cord. Two weeks post conception, the cells of the blastocyst organize themselves into an embryo through gastrulation. The process takes place inside uterine lining in humans. Cells align themselves and organs begin to develop. Cells communicate with each other through chemical messages, which facilitate activation of correct genes and production of right proteins. Proteins are the building blocks of human body.

Heart is one organ that works during early weeks of embryonic development. Other organs and systems develop much later. During early stages of development, the gender of a baby can only be known by examining its chromosomes. By the beginning of third trimester all organs are in place and the fetus main job is growth. In this phase, fat accumulation, even in the brain due to myelin manufacture begins essential. The babys need for fat eventually increases to a point where it must come out of the womb for survival. For birth, the cervix opens up to about four inches. Baby goes through significant contractions before it can come out of the narrow opening of cervix. If the same is not possible a Cesarean section is used.

ANSWERS TO THE QUESTIONS

1.  Actin and myosin are directly involved in muscle contraction. They are some of the proteins that are necessary to maintain the structural integrity and function of the sarcomere. Actin is the most abundant protein in the typical eukaryotic cell. This protein is highly conserved, and forms a huge variety of structure in cells in concert with a huge numbers of actin binding proteins. Myosins are a large family of  Motor proteins motor proteins and are responsible for Actin actin-based  Motility motility. Each myosin molecule has a tail which forms the core of the thick myofilament plus a head that projects out from the core of the filament. Contact with actin causes the myosin head to swivel. During the swivel, the myosin head is firmly attached to actin and thus the binding of the two filaments. If under certain circumstances that the two myofilaments are extracted and placed in a beaker, the molecule that must be added to the beaker to make the filaments unbind is Adenosine triphosphate (also known as ATP). Since, at the end of the swivel of a myosin head, it fits into the binding site on the cross-bridge  this breaks the bond between the cross-bridge (myosin) and actin, resulting in the eventual unbinding of both proteins.

2.  Different types of athletes usually have a unique composition of muscle tissue in their body, that being the kind that suits their sport the best. The difference of enzyme activity or the concentration of substances in the muscle tissues depends on the nature of the activities that they perform. In examining biopsies taken from the gastrocnemius muscles of the athletes, the researcher would notice that the succinate dehydrogenase (SDH) activities were highest and the percentage of slow twitch fibers are most predominant among the 10,000m runners followed by the 100m dash athletes then the weight lifting athletes. Oxidative capacity of slow twitch and fast twitch fiber types was also greater in the 10,000m dash athletes than in the other groups of athletes.

3.  Given the symptoms, it means that Speedy sprinter has no ability to raise her right heel off the ground while her toes are in contact with the ground. She is still able to turn or move the forepart of her foot away from the midline of her body. Her ability to bring the dorsal surface or the top part of her foot towards the anterior surface of the leg is more than normal. Meaning, she can flex her foot further than most people can with ease. Her calf muscles, on the other hand, were said to be bulging. Injury to the calf muscles is very common in athletes. The muscles may become inflamed from being torn due to a sudden impact or due to overuse. In the case of Speedy sprinter, anti-inflammatory drugs and physical therapy may be necessary because these symptoms may lead to more complex problems if not treated correctly.


Hypothyroidism

Hypothyroidism is a deficiency of thyroid hormone. It can either be primary or secondary process. A condition whereby the thyroid glands produces insufficient or low amount of thyroid hormone is termed as primary process while the total lack of secretion of this hormone is known as secondary hypothyroidism (Bharaktiya, Orlander, Woodhouse  Bhalla, 2009 ). The latter condition is characterized by lack of thyrotropin (i.e. thyroid-stimulating hormone TSH) from the pituitary gland or thyrotropin-releasing hormone (TRH) from the hypothalamus (Bharaktiya et al., 2009). Those who suffer from this condition vary from asymptomatic to rarely, coma with multisystem organ failure (myxedema coma).

The most common condition in the USA is caused by autoimmune or Hashimotos thyroiditis, in which the immune system attacks the thyroid gland. According to National Endocrine and Metabolic Diseases Information Service (May 2008) publication, autoimmune is a disorder whereby the bodys immune system reacts against its own cells and tissues instead of protecting the body against any foreign body which is the primary function of the immune system.

The Physiological Effects of Hypothyroidism                
Heart disease
Studies have shown that hypothyroidism causes heart disease and related complications. In his book, Solved The Riddle of Heart Attacks, published in1976, Dr. Broda Barnes strongly suggested that heart disease was caused hypothyroidism (cited in Alternative Medicine Angel n.d.). Although his was done decades ago, recent studies done in the 1990s have shown that there is a relationship between thyroid activities and fat metabolism. Blood-fat levels will increase with an underactive thyroid and decrease with an overactive thyroid (Alternative Medicine Angel, n.d.). When the thyroid hormone (TH) level falls, the liver will not function normally and therefore excess cholesterol would be produced together with excess fatty acids and triglycerides which will enhance the chances of heart disease (Philips, May 2001).

Poor circulation
As the heart disease gets stronger, it decreases the blood circulation to the various body parts and organs including the heart. Lack of proper blood circulation in turn will result into flaky, dry or cracked skin and ever cold hands and feet. This is due to shortfall in circulation of blood which interferes with the bodys ability to warm the extreme parts. The delivery of various fatty acids and nutrients will also be interfered with by the poor blood circulation which will explain the dryness of the skin. This problem would normally be rectified by the normalcy of the thyroid.

Depression and Fatigue
The mental arena is highly affected by the thyroid hormone imbalance (hypothyroidism). Due to this, the hypothyroid people sleep easily but never enjoy the sleep. Therefore when awake, they experience fatigue, memory lapses and loneliness. These experiences may result into severe stress and depression that alters even normal daily functions. As cited by Philips (May 2001), some anti-depressants worsen the conditions of the hypothyroid patients because the medications depress T3 levels. In her book, Prozac Panacea or Pandora, Dr. Ann Tracy discovered that those who are taking the anti-depressant Prozac have been found to be initiating most of the shootings witnessed in the USA (Alternative Medicine Angel, n.d.).

Weight Loss
In cases of hypothyroidism, the normal blood circulation is depressed, may as a result lead to poor metabolic rate and subsequently weight loss. The thyroid hormone imbalance has effect on the cardiovascular fitness because it helps to control the heart rate and blood pressure (Philips, 2001). Therefore, imbalances in the heart rate and blood pressure would impair respiration and supply of oxygen making the body not to respond to exercise and muscles would never strengthen.

Conclusion
It is important to know the effects of low thyroid in the body. This would help one make informed and prompt choice on when to seek diagnosis, because as Dr. Nelson (2005), puts it, the thyroid always acts as the bodys gas pedal. An overactive thyroid makes the body to react too fast while an underactive one makes the body systems too cold and to run slow.

Mens Preoccupation with Penis Size

A mans manhood has been considered his pride and joy for centuries. It is said that the one way to break a mans spirit is to make a mockery of his manhood, his penis size to be exact. One of the main reasons that men have become preoccupied with their penis size is the perception put into place by their female counterparts, many of whom believe that bigger is better. The preoccupation with penis size has become such a common topic that a number of myths to determine a mans penis size without actually seeing it. The first one is dependent on the size of a mans hands where it is said the bigger the hands, the bigger the penis. It has also been claimed that a man with a bigger shoe size is guaranteed to have a larger than average penis. The female claim to this theory is the fact that it offers more pleasure during sexual intercourse. There has also been the perception that ones penis size is dependent on geographic factors, with those of African descent having the largest and those of Asian descent having the smallest. The obsession with penis size has also been fueled by the media and pop culture as seen in advertising and the media in general, which is why women have subconsciously taken on that perception. For example, condom advertisements have been said to be in favor of men with large penises. This is considered an unfair advantage over those with smaller penis sizes as they are pressured to work harder to prove to a woman that they are just as competent as their larger counterparts.

When it comes to the disadvantages of having a small penis, the only one that has come into light is, as initially stated, is the fact that females prefer a larger sized penis over a smaller one. According to the human body, a females erogenous zone when it comes to sexual intercourse is found in the first third of the vaginal cavity and this is because the nerve supply is located there. So is it safe to say that the smaller the penis, the better the sexual experience Well, yes and no yes because a smaller penis may be advantageous in stimulating this vital part of the vagina. However, this does not guarantee a fulfilling sexual experience at all times. This is where a man who is well endowed has an advantage because many women believe that a man who is sexually experienced, penis size notwithstanding, can offer sexual satisfaction.

In as much as a small penis could turn off a woman that prefers a man with a large penis, there is definitely a thing such as too large a penis. This is because a large penis can loosen and caused damage to the vagina. A large penis can also bring about an uncomfortable sexual experience as the strain to the vagina and repetitive penetration can cause pain and discomfort. On the side of the man with an extremely large penis, it can bring about health issues as the blood flow to handle an erection may be too much for the body to handle. While most men love the attention they get from having their penis visible through their clothes, it can be uncomfortable when it comes to wearing tight-fitting gear such as a swimsuit or a pair of briefs.

Men as the Sexually Experienced Gender
From time immemorial, men have been pressured to be automatically sexually experienced, and this is because if their performance comes short, then the female counterparts in that given sexual experience are bound to announce their negative reviews to the most critical group in society their girlfriends. They also expect men to be the ones to initiate the chase and follow it through to the end with the precision and romance seen in films and on television. It had been, for a long time, seen as the order of things for the man to approach the woman, a scenario that has since reversed as the females have become more empowered and are now going after their object of desire. For a long time, men have been considered the king of their caste for being able to rein in as many sexual partners as possible, while women that attempt the same are considered promiscuous and are viewed in a negative light.

Through this stereotype, the misconstrued theory that when a woman says no, it really means yes came to be. This is because men, as the natural predators, have been led to believe that the female enjoys the chase and will never admit to being interested until the man proves himself to be worthy. There have been countless cases of date rape and assault because some men will not take no for an answer and believe that conquering the female is the ultimate goal, no matter what it takes. The pressure on men to be sexperts has caused many men to engage in promiscuous activities. This means that they will strive to sleep with as many women as possible so as to not only gain experience but also a reputation as well as being considered by his peers as a sex machine. The main setback with this plan is that it puts those involved at risk of getting sexually transmitted diseases as well as unplanned pregnancies.

The portrayal of the ideal man physically and otherwise by the media and society has driven men to engage in a number of physique altering measures. To begin with, the idea sexual being has been portrayed as muscular and well-built. It is for this reason that men will risk their health by taking on strenuous workout session as well as taking steroids and muscle enhancing drugs so as to gain that bodybuilder frame. Some of these drugs and supplements have been considered a health risk by the FDA and other health authorities but due to pressure from society, many men will still take them to acquire the desired results in record time.

The pressure to be more sexually experience also ties in with the perception that penis size and high sexual performance are a requirement for a successful sexual relationship. This means that men will use means like pumps that have been said to enlarge the penis and will also take drugs like Viagra so as to fulfill the womans sexual needs. Some claims have been made that taking hard drugs like cocaine, heroin and even marijuana helps in maintaining an erection and high sexual performance, which means that those that resort to these measures could be ruined not only physically but psychologically as well.

The porn industry is also to blame for the pressures put on men to put their best foot forward at all times when it comes to sexual intercourse. This is because there are a great number of people that will want to attempt what they see in these films so as to prove their sexual prowess. The downside to watching pornography is that one could get addicted to them and could cause a major strain in relationships.

It is important to note that relationships built on more than just sex are more successful and those involved should be able to freely discuss this aspect of their relationship and in that way, both parties can move ahead knowing that they can be comfortable during intercourse.

Icons and their HIV status
It was in 1991 when basketball great Magic Johnson publicly declared his HIV positive status to the world. This is not to say that he was the only one that had this life-threatening disease, but he was the first to let the world know. Others included NWA rapper, Eric Easy E Wright and rock band Queens front man, Freddie Mercury but there condition was known when their deaths came to pass.

Celebrities and role models in the music, film, business and any other industries are considered to be indestructible by their fans and followers and the discovery that a disease like AIDS can affect them is considered to be a devastating blow.

HIV is a disease that is not only transmitted through unsafe sexual activity, but it is also transmitted through sharing needles and transfer of bodily fluid from those already affected. Many celebrities have been drug addicts which means that there may be times that they will share needles as well as other paraphernalia to ingest these drugs. This is one way that they can actually catch this virus. Exchange of bodily fluids means that any fluid found in the body like saliva, blood, semen and so on, of a sick person that is transferred to a healthy person can also cause the spread of the disease. Another way that HIV is transmitted is from a sick mother to her unborn child. Thanks to advances in health and science, this is a condition that can be tackled at an early stage but there are those that may still be born with it.

Many people have been led to believe that it is only through unprotected sex that one can catch the HIV virus and it would be easy to assume that this is the only way that celebrities would be exposed to this disease. This is because with the celebrity status comes worship and admiration from many, some of who will offer up their bodies as a sign of loyalty. An initial reaction to finding out that a celebrity that one looks up to is HIV positive is the fact that one will lose their respect and admiration for them because they are not as invincible as many make them out to be. It will make a fan judge them in a negative light and will even be the first to criticize them. It is then important to actually know and learn how they may have gotten the disease. One may not look at them in the same way they did but it will shed some light on the situation.

Regardless of how a celebrity, icon or any other person catches the disease, it is meant to serve as a lesson to all. It will teach people to be more careful and safe during sexual intercourse. This means that protection like condoms is an absolute must. It is also important to earn that one should not have many sexual partners. One should be sure to be regularly tested and must know that HIV status of their partner so as to avoid the spread of AIDS. Females who may have the virus should avoid getting pregnant and should they be pregnant, they must exercise caution so as to ensure the child is born free of the virus.

Celebrities and those in high society have high-end doctors, drugs and medical procedures at their disposal, which is why people should be aware of the disease and how it can affect ones lifestyle. If my favorite icon was diagnosed with AIDS, then it would be a definite wakeup call that will teach me to engage in safe sex, stick to one sexual partner, get regular tests done to be safe and sure and also avoid situations where suspicious bodily fluid exchange could be a risk. This means that one should stay away from drugs and reckless behavior as well as ensure that any blood transfusions and donations are undertaken at credible and well-known health institutions so as to avoid accidental transmission of the disease. I would respect a public figure that openly declares their positive status as this means that they wish to show the world that anyone can catch the virus if not careful and is not restricted to class, race, sexual orientation or geographic location.

Should Condom Advertising be Banned
Condoms have been considered to be the worlds answer to safe sex. This is because it will not only protect from unwanted pregnancies, but they also protect partners from transmitting sexually transmitted diseases. Condom advertisements have been banned from televisions as they have been considered by those of the older generation as an encouragement for young people to have sex as long as a condom is present as well as promoting promiscuity and underage sex. It is interesting to note, however, that there are advertisements shown for sexually transmitted disease medication.

Religious leaders and parents at large have been proposing that abstinence should be the ultimate goal when it comes to sex education. It is believed that by showing these condom advertisements that abstinence is being placed on the back burner. Sex has, for a long time, been considered a taboo topic and it has mostly been left by the parents and guardians to the education system, religious institutions and even the media to teach the youth about sex. This may be one of the reasons why many parents are unable to cope with situations where their offspring get pregnant or get sexually transmitted diseases.

In many nations, condom advertisements have been cautiously accepted but they can only be shown on late night television so as to avoid the young from seeing these advertisements. In my opinion, covering it up only makes things worse and it is important that these advertisements are shown. These advertisements could actually be an interesting place to start having a talk with the youth about sex. Due to changing times and change in family values because of society, abstinence is a hard sell and it is instead important to teach the youth the importance of safe sex. In that way, should they decide to engage in sexual activity, they will not be at risk of transmitting sexually transmitted diseases as well as getting pregnant.

It is not acceptable to allow herpes advertisements to be broadcast yet condom ads are frowned upon. If anything, the probable lack of condoms in the picture is the reason why the herpes medication is now needed. To avoid paying a lot of money to get rid of these diseases, it is only reasonable and fair to let condoms play a big part in sex education through the media.

What is most disturbing is the fact that the media glorify sex and other ill of our society. Many believe that they do not wish to show these sobering images of condom advertising because it goes against what they are promoting and this is the fact that sex sells. If the advertisements are in good taste and in no way promote irregular sexual behavior, then it is only fair that it is shown. Many of these advertisements are mostly created to target adolescents as they are the most curious and if not checked, most reckless. Many religious groups insist that the funds used to promote condom campaigns should be instead put into raising awareness about cancer and other life-threatening conditions. What is mostly overlooked is that AIDS is an incurable disease, as compared to cancer, and it should also be given the same airtime as these other disease.

In the end, it is all about the packaging. If the advertisements seem to be promoting promiscuity, then by all means ban them. However, if the condom advertisements are geared towards promoting safe sex as well as letting the public know their real value, then it should definitely be made public through advertising. It should not be shown when those under a certain age are likely to be watching television, but it should also not just be shown after primetime because it is important that as many relevant groups like married couples, the youth and those that are generally sexually active will be able to view it.

A Small-Cell Lung Cancer Genome with Complex Signatures of Tobacco Exposure

Increased attention has been placed on lung cancer as the annual death rate from lung cancer continues to rise globally. Governments and health sectors around the world work side by side as they attempt to combat this serious problem. Recent findings indicate that tobacco smoke causes cells to mutate resulting in lung cancer. An article by Pleasance et al., which was published in the January 2010 issue of Nature, relates the use of massively parallel sequencing technology to sequence a small-cell lung cancer cell line in an attempt to gain insight on the mutation process caused by tobacco smoking. The purpose of this paper is to review the study presented in said article by considering several factors, such as the objectives of the article the useful features of the article and the broader implication of the research discussed in the article.

Keywords lung cancer, mutation, tobacco smoking, sequencing,  molecular biology, small-cell lung cancer, genome.

I. Introduction
According to Hong (National Foundation for Cancer Research, n.d.), the leading
cause of cancer-related death in both men and women is lung cancer. The severity of the lung-cancer related problem can be observed in the U.S., as reports indicate that an estimated 219,440 new cases and 159,390 deaths from lung cancer are expected in 2009.

In view of this, the article by Pleasance et al. (2010) discusses a research conducted to determine the effects of tobacco smoking in the activation of cancer genome resulting in lung cancer. A genome can be defined as the total amount of genetic information in the chromosomes of an organism, including its genes and deoxyribonucleic acid (DNA) sequences. In the research, the authors attempted to determine the cancer-causing mutation of a human DNA caused by tobacco smoke.

II. Method
In the article, the researchers analyzed the mutation stages of the cancer genome by applying a method called sequencing, which is the process of determining the precise sequence of nucleotides, or group of molecules, in a sample DNA. To get better results, the researchers used a massively parallel sequencing technology in the sequencing of NCI-H209, which is a small-cell lung cancer (SCLC) cell line. The research derived cancerous cells that was transmitted to the bone marrow of a 55-year-old male with SCLC. The cells were obtained before the man underwent chemotherapy. Findings indicate that more than sixty cancer-causing chemicals are found in tobacco smoke causing cells to mutate. According to the researchers, the use of massively parallel sequencing method allows biochemists to learn more about genome-wide mutation.

III. Results
The article highlights the use of massively parallel sequencing method in order to identify the carcinogens, or cancer-causing chemicals, found in cigarette smoke. Moreover, the method was able to recognize the point wherein the cell s attempts to repair DNA damage was partially successful. The study found an unknown gene expression-linked repair pathway that operates on both transcribed and non-transcribed DNA strands implying that at least two separate DNA repair pathways have been enlisted to protect the NCI-H209 genome. According to the authors, the findings illustrate the purpose of the research which is to highlight the potential of DNA sequencing in making breakthrough advances in cancer development research .

IV. Discussion
The introduction of the Pleasance et al. article provides a background on the severity of the health problem being faced globally in relation to smoking as they presents brief stastistical data on the rising number of lung cancer cases worldwide. The authors were also able to highlight the lung cancer-causing risks associated with direct tobacco smoking and with indirect exposure to tobacco smoke. The article s introduction also stresses the importance of having a comprehensive understanding of the mutation patterns in human cancer as this could lead to further advances in molecular biology.

As the rest of the article progresses, it becomes confusing as, what is typical in a scientific journal, highly technical terms are being used throughout the article. The article provides an attention-grabbing idea, but an average person with no extensive background in the field of molecular-scale biological sciences will find it difficult to understand.

The research findings discussed in the article is indeed a breakthrough in terms of cancer research. One of the strong aspects of the study is that it focused equally on various components such as the pathogenesis of cancer, the advent and use of massively parallel sequencing technologies and genome mutation. The broader implication of this study is that, with the additional scientific knowledge brought about by this study s findings, it will serve as a motivating factor for next-generation scientists to produce more findings that can save more lives.

In addition to the findings mentioned in the abovementioned article, another related study has been conducted by Waun Ki Hong (National Foundation for Cancer Research, n.d.) as, in a somewhat similar manner to Pleasance et al s approach, his team has developed individualized targeted therapies for cancer treatment by targeting specific molecular abnormalities in individual patients.

V. Summary and Conclusion
The yearly number of lung cancer-related deaths globally continues to grow at an alarming rate. Reports indicate that lung cancer is now the most common type of cancer in the world, with an estimated total number of 1.2 million cases occurring annually (cited in IARC, 2004). This is an indication that the problem of lung cancer is getting out of control and needs to be addressed immediately. The research findings presented in the article  reviewed is another step to solving the rising cancer mortality problem. As the article points out, cigarette smokers are not the only casualties of lung cancer but also non-smokers who may be exposed to tobacco smoke.

In conclusion, it is interesting to note that the field of biological science, although wide-ranged, is interconnected in every way, as we see that each field has a crucial role to play in its aim for the advancement of science and the betterment of people s lives. The article is an excellent example of the importance of pushing one s self to further heights and the continuation of acquiring new knowledge as we go through our everyday life.

LAB EXPERIMENT FOR CARDIOVASCULAR PHYSIOLOGY

The cardiovascular system includes the heart and blood vessels it is related to the respiratory system as the oxygen we breathe is delivered through our blood. In this experiment, we will understand fully the factors that affect breathing rate and how well our heart functions to supply properly the body with oxygen. Both systems are controlled by the central Nervous System specifically the brain.

The first activity is to measure pulse rate or heart beat rate per minute. Record
Next is to measure blood pressure using sphygmomanometer. Record

 Run consecutively for an hour and measure again pulse rate per minute.

In this experiment, the dependent variable is the pulse rate and the independent variable is the running activity.

The contents of the blood also affect the rate at which it is delivered. Therefore, it is important to determine the blood components in order to understand fully the rate at which the heart beats.

Determination of blood cholesterol using the centrifuge to separate the plasma from the serum is the initial step. Do a series of tests using the spectrophotometer to determine cholesterol level of your serum and plasma cholesterol. High cholesterol in the blood vessels indicates low supply of blood and oxygen while low cholesterol level indicates a smooth flow of blood.

In this test, the independent variable is the cholesterol level and the dependent variable is the pulse rate or heart beat rate.

With this, the results of the cholesterol level and pulse rate can be correlated to each other. High cholesterol content of blood makes the heart work harder to be able to pump sufficient blood and deliver oxygen throughout the body. Low blood cholesterol level gives a normal pulse rate since the heart does not need to work extra to pump blood.

Genetically Marking the susceptible Gene for Beet Mild Yellows in Arabidopsis thaliana

Abstract
The sugar beet pathogen Beet Mild Yellows Virus was inoculated using the aphid Myzus persicae into the model plant, Arabidopsis thaliana. This produced two plants one which expressed possible resistance in the form of BMYV-ss-Sna-1 and the other, susceptibility BMYV-SS-Col-0. After crossing Col-0 and Sna-1 to create an F1, the offspring was self fertilised to create an F2 generation which exhibited a 31 ratio of susceptibility to resistance. The susceptibility locus, was investigated by using a technique called simple sequence repeat (SSR) polymorphism. Mapping of the resistance locus was first attempted by randomly selected SSR markers covering chromosomes 1 to 5. It was subsequently shown that the resistance gene resided on chromosome 4. Linkage was demonstrated with the microsatellite markers CIW6 and G4539 on chromosome 4 which were mapped relative to the resistance gene BMYV-ss. This discovery proves significant as further markers can now be used to flank this region and further analysis can be done on the resistance gene in Arabidopsis thaliana.

INTRODUCTION
Sugar beet background
Sugar beet is a crop of immense economic value as it is used in the manufacture of sugar and is used as animal fodder. It is also a major component in the manufacture of Bio-fuel.  Even though the British beet sugar industry began during the early 1900s, the first extraction of sugar, however, was demonstrated by the Prussian chemist Andreas Sigismund Marggraf, in 1747 a method in which alcohol was used to extract sugar from beets. Yet this method did not go into industrial scale production, until after the blockade of continental ports which occurred during the Napoleonic wars and prevented export supplies of sugar cane from the West Indies. This encouraged Franz Karl Achard to begin selective breeding from White Silesian beet, which was then a fodder crop. This led to the first sugar beet factory in Prussia in 1801 which contained at the time only about 4 sugar incorporated into the beet.

In the UK, the beet industry began during the 1900s with the first factory being built by the Dutch of Cantley in Norfolk in 1912. This then shot up to 17 factories during the 1920s and the crops were processed by 13 autonomous companies. In 1936, those factories were amalgamated by the Sugar Industry Act to from one big multinational corporation, British Sugar PLC. They were to manage the entire domestic crop a development which marked a significant stage in the progress of the UK beet sugar industry.

Today, British Sugar is contracted with 4000 farmers and between September and March, as much as seven and a half million tonnes of sugar beet are delivered to the factories. In one factory alone, 14000 tonnes of sugar beet are processed in one day.

Fig 1 Shows the sugar processing and industrial use of Sugar Beet at the British Sugar factories.

British Sugar produces over 1 million tonnes of sugar in the UK and an additional 450,000 tonnes of animal feed from sugar beet pulp. It also provides other vital substances through the production of sugar beet such as recycled stones for building, lime for soil conditioning and soil for landscaping. They are also used in combined heat  power plants to generate and export electricity enough for 350,000 people and use the combustion gases to grow 80 million tomatoes. More recently and almost more importantly, they are being used to as alternatives to fossil fuels which are fast depleting. British Sugar has invested in the UKs first bio-ethanol plant, producing 70 million litres of renewable fuel through the production of Sugar Beet, to help prevent a global economic crisis (British Sugar n.d.)

It is clear then, that sugar beet production will always be a necessity. However, it is not a simple crop to grow as it suffers from many constraints. During its first growing season it is used for commercial harvesting and can produce as large as 2kg tubules which contain 15-20 sucrose by weight. During its second season the nutrients in the roots are used to produce flowers and seeds in cold weather, even though the process cannot take place in extreme cold conditions due to the crops poor frost resistance. During its seedling stage it is a poor competitor with weeds and can also be damaged by Heterodera schactii, a pathogenic nematode in beet. Sugar beet also suffers from viral infection which inhibits the plant growth and sucrose production.

Beet Mild Yellows Virus (BMYV)
Sugar beet crops worldwide are affected by several different aphid-transmitted yellowing viruses. In Europe, the main threat is through viral infection of the closterovirus, Beet Yellows virus, and the polerovirus BMYV (Beet Mild Yellows Virus). BMYV is found frequently in northern and western parts of Europe whereas BYV (Beet Yellows Virus) is found in the south (Smith, 1987). It causes beet leaves to yellow prematurely and causes a reduction in photosynthetic activity as well as decreasing root weight and sugar concentration in infected plants (Smith and Hallsworth 1990). It has a large effect on the yield if the virus infects the plant during early growth, decreasing the overall yield by 30. This has been estimated to have cost the national sugar industry 24,700 tyear which is the equivalent of 1.8 of the countries yield and a staggering 5.5 million.      

The BMYV virus is a member of the genus polerovirus which is part of the family Luteoviridae and is related to the Beet Chlorosis virus (BChV) and Beet Western Yellow virus (BWYV). It is common in Europe however as of yet has not affected the agricultural production in the USA as no traces have been found. The symptoms include interveinal and uniform yellowing of leaf tissue with the thickening and brittleness of older leaves, which resembles both BWYV and BChV symptoms (Russel, 1962). BMYV is an aphid transmitted virus through the vector M. persicae. Studies by the Plant Breeding Institute showed that unlike the beet yellows virus (BYV) it is a true persistent virus. They examined the transmissions and results showed that successful transmissions occurred when M. persicae was fed for 24hrs, however they reached maximum transmission efficiency after three days of infection feeding (Russel, 1962).  They also proved that the BMYV persisted for long periods within M.persicae and a large proportion of aphids which had been fed on infected sugar beet for four days managed to transmit the virus after 9 days on Brassica pekinensis, which was supposed to be immune to BMYV. It was also shown that unlike BYV aphids, aphids which had acquired BMYV could still transmit the virus after moulting without access to further sources of virus.

Fig 3 Aphid vector for BMYV Myzus persicae, BMYV is able to maintain persistent virulence within M. Persicae. Luteoviruses are phloem-limited viruses which are transmitted by aphids in a nonpropagative persistant manner. Like other poleroviruses, BMYV is limited to the vascular tissue of its hosts and mechanical inoculation is only possible in mixed infections with umbraviruses (Mayo et al, 2000). The spread of the aphid is dependent on season, however due to the long lasting persistence it makes BMYV infection a serious problem.

The vector specificity of luteoviruses transmission suggests that specific cellular receptors in the aphid interact with the capsid.  The major component of the luteovirus is the -22kDa polypeptide encoded by the open reading frames (ORF). BMYV has a genome organization with six large ORF located on a single-stranded positive-sense RNA. The ORFs are arranged in a 5 gene cluster (ORF0-2) and a 3 gene cluster (ORF3-5) (Guilley et al, 1995). ORF3-5 expression involves at leastone sub-genic RNA.

Resistant Mechanisms
During the co-evolution of plants and their pathogens, the pathogens developed a wide variety of strategies to infect and exploit their hosts. In response to this pressure, plants countered by deploying a range of defence mechanisms. Resistance to a pathogen is often accompanied by a response known as the hyper-sensitive reaction which is the rapid, localized death of cells at the infection site. In the most documented systems the occurrence of the hypersensitive reaction depends on the possession by the plant and invader of corresponding resistance (R) and avirulence (Avr) genes, also known as gene for gene interaction (Kombrink and Schmelzer 2001). In gene for gene interactions involving viruses, viral gene products identified as elicitors, capable of triggering the hypersensitive response include replication proteins, viral capsid proteins and viral movement proteins (Erickson et al 1999, Culver et al, 1994). Acquired resistance has been best characterised with in tobacco and cucumber. During the 1960s it was demonstrated that infection with tobacco mosaic virus can cause tobacco to become resistant to diverse viral pathogens. This was termed systemic acquired resistance (SAR) which is proven to be effective against fungal and bacterial pathogens.

Arabidopsis has been used to map BMYV and recognise the resistant genes. It is used as it has a small genome, rapid life cycle, high transformation efficiency with a completely sequenced genome and powerful reverse and forward genetics. It belongs to the Brassicaceae or Crucifer family, which includes the genera Arabis, Brassica and Cardamine. It is favoured for its small genome size (114.5125Mb), extensive genetic physical maps of all 5 chromosomes, its rapid cycle and its prolific seed production and easy cultivations to produce polyploidization (Chen et al, 2000). The Arabidopsis model polyploidy model provides a powerful genetic and genomic resource for elucidating mechanisms of gene and genome duplication. Genome-wide changes in gene expression can be comparable with changes in genome organisation as well as a chromatin structure in auto and allopolyploids which provide a mechanistic view of polyploidy effects on the regulation of homologous gene. (Chen et al, 2000)

High-throughput sequencing has generated abundant information on DNA sequences for the genomics of various plant species. This included the completion of the model draft of Arabidopsis thaliana in 2000 (Chen et al, 2000). This also includes other express sequence tags from other important crop species have been mapped and generated to produce biotechnological tools and have annotated thousands of sequences as functional genes. The task of bridging this DNA sequence information with particular phenotypes relies on molecular markers (Chen et al, 2000). This is where my project will be focusing by using an efficient PCR based AFLP (Amplified Fragment Length Polymorphism) technique to generate polymorphic markers around targeted putative resistant gene sequences against BMYV.

Microsatellite Analysis
Molecular markers linked to resistant genes are useful to facilitate genes in breeding materials.
To locate resistance loci, they must be mapped relative to other markers. Mapping of genes in sugar beet is somewhat behind mapping in other crops, e.g. the cereals. Before the advent of molecular markers, disease resistance gene mapping in sugar beet was slow and difficult and only one such gene, C for curly top resistance, Owen and Ryser, (1942) was mapped. The reasons for this slow progress in sugar beet were

Sugar beet contains relatively few morphological markers that can be used for mapping (Francis et al, 2000).

Most sugar beet pathogens do not exist as physiological traits that can elicit trait-specific resistance responses in the host therefore probably few gene-for-gene interactions exist that can be easily scored in a mapping population (Francis et al, 2000).

Resistance to many diseases appears to be controlled by one or more quantitative trait loci (QTLs) and these cannot be mapped without molecular markers (Francis et al, 2000).

The mapping of F2 populations with 3 1 segregation ratios is difficult to breed into sugar beet as in general it is an allogamous species and homozygous parents can only be produced if the self-fertility gene is present in the material, otherwise doubled haploids must be developed (Francis et al, 2000).

Microsatellites are tandem repeats of DNA sequences of only a few base pairs (1-6bp) in length, the most abundant being the dinucleotide repeats. It was termed by Litt and Luty (Cregan 1992) to characterize the simple sequence stretches amplified by PCR (polymerase chain reaction) (Gupta et al, 1996). They are abundant and occur frequently and randomly in all eukaryotic nuclear DNAs examined (Gupta et al, 1996). Their frequencies vary significantly among different organisms (Wang et al, 1994).  The length differences are attributed to the variation in the number of repeat units at a particular SSR locus caused by slippage during replication (Gupta et al, 1996).

The benefits of using microsatellites provide the following
They provide alleles that exist in a population and the level of heterozygosity is extremely high.
The markers are co-dominant (contribution of both alleles visible in phenotype)
The markers are inherited in Mendelian fashion and thus for our investigation can be used for linkage analysis (Gupta and Varshney, 1999).

The frequencies of microsatellites have been examined in chloroplast genomes, since complete or partial sequences of chloroplast genomes are now known from several plant systems. These include rice, tobacco and maize (Gupta and Varshney, 1999) and they predominantly included short to medium sized stretches of mononucleotide sequences. It was shown that within these plant systems while fluorescence in situ hybridization suggested apparent clustering of microsatellites, genetic mapping in several cases demonstrates uniformly distribution throughout genomes (Gupta and Varshney, 1999).

DNA polymorphisms are detected by PCR by two methods. They either target individual loci using specific primers bordering the microsatellites (Gupta et al, 1996), or by using primers as synthetic oligonucleotides which are complimentary to a microsatellite motif randomly distributed throughout the genome (McCouch et al, 1997). Both assays typically carried a high information content and had been used for mapping and gene tagging (McCouch et al, 1997). The investigation will be using SSLP (simple sequence length polymorphisms) as it also allows restriction enzymes to be used to resolve digested CAPS (cleaved amplified polymorphisms), which has been previously used on tomatoes and barley (Davila et al, 1999).

AIM
So far within the investigation of BMYV a susceptible gene has been found within a mutated Col plant which has been crossed with a possible resistant gene from a Sna-1 plant. The aim of my project was to investigate polymorphisms in the mutated Arapidobsis thalium, Columbia and Sna-1. The purpose was also to discover a marker to target the susceptible gene (S) for Beet Mild Yellows Virus, in Arabidopsis thalieum. To do so various markers from chromosomes 1-5 were used to search for the resistant region of each chromosome. This is because the susceptible region is dominant SS and therefore has a 75 region of the chromosome, whereas the resistant gene ss will give a more accurate region as it is much smaller.

METHOD
Inoculation
Arabidopsis thaliana was previously inoculated with BMYV infected Myzus persicae. This produced two plants (although not proven), Sna-1 and Col-0. The Sna-1 contained alleles BMYV-ss and had shown mutational resistance. The other Arabidopsis thaliana is thought to show susceptibility towards BMYV and therefore could contain the alleles SS as these were thought to be of a dominant phenotype. Sna-1 and Col-0 were bred to form the F1 generation which self fertilised to form F2 generation. The F2 plants will be Ss, sS, or SS and susceptible or ss and resistant therefore there is a 31 ratio.

DNA extraction
The Arabidopsis leaves were added to 700l of Extraction Buffer (100mM Tris pH 7.5, 500mM NaCl, 50mM EDTA, 1.5 SDS and 0.1 -mercaptoethanol) were added to a 2.5ml microfuge tube and then ground using a blue homogeniser until the leaf product had dissolved. These tubes were then incubated for 12 mins at 65p C. The tubes were then centrifuged at 13,000rpm for 8 minutes. 700l of the supernatant was placed in clean microfuge tubes and 700 l of phenol chloroform was added and the tubes were further centrifuged at 13,000 rpm for 8 minutes. Then 540l was used to clean the microfuge tubes and was added to 60l of 3 M NaAc pH 4.8 with 600l of isopropanol mix and incubated for 2 hours at -20p C. The tubes were then centrifuged for 15 mins at 13,000 rpm, the supernatant was removed and the remaining pellet was washed with 80 ethanol. The ethanol was later  drained and the pellet was re-suspended in 50l sterile distilled water.

Random Frequency Length Polymorphisms
This approach amplified and performed using a 5anchored SSL primer. The amplified products resolved length polymorphism that presented either the SSL target site itself or at the associated sequence between the binding sites of the primers. This also allowed the amplified products to be digested with restriction enzymes to gain the genetic map if linkage occurred.

PCR Mixture
The PCR methodology was used under standard procedures set by PROMEGA using GoTaq Flexi. For one reaction mix the following PCR mixture shown in table 1 was added to 2.5ml microfuge tubes. The DNA polymerase was kept in the freezer and added after the DNA preps to prevent early digestion and denaturing of the enzyme. The concentrations remained the same throughout for all the primers apart from G3883 on Chromosome 4 which had used 1.5MgCl2 (according to the special condition required in TAIR)

Table 1 List of reaction components used to make a PCR product.
ComponentFinal Volume5 x Polymerase Green Go Taq Buffer4l20mM dNTPs0.2lForward Primer (10M)1lReverse Primer (10M)1lGo Taq Flexi Polymerase0.1lMgCl21.2lSterile Distilled Water11.5l
The PCR cycle
Table 2 The PCR cycle
StepTime SecondsTemperature CA3094B3055C3072DRepeat from Step A 34 timesE30072

Table 3 A list of the Microsatellite Markers from Chromosome 1-5 and the region in which they target Columbia
Microsatellite MarkerChromosome NumbercMMbpCol-0 lengthNGA 1111115.5526.69111NGA 248142.1723.45143NGA 128183.3220.22180ATH ANTPASE1117.8628.5385CIW 221.19105CIW 326.4230NGA 1126250.65191BIO 2267.018.01141NGA 3235.870.44260NGA 17239.910.79162NGA 162320.564.61107NGA 126316.353.65119NGA 6386.4123.03143NGA 12422.926.39247NGA 8425.565.63154DET 1431.446.35DHS14108.5418.53NGA 76568.410.42231CA 72529.64.25124NGA 225514.311.51119NGA158518.121.69108NGA 106533.3575.635157

Restriction Enzymes
To G4539 and G3883 restriction enzymes were added for digestion after the PCR cycle. The restriction enzyme HindIII was used for G3883 and G4539 was tested using both HindIII and RsaI which cuts at 300bp.

1l from each restriction enzyme was added to the PCR tubes containing the DNA preps. This was then incubated at 37C overnight.

Microsatellite Analysis
The PCR reactions were used with the microsatellite markers in table 3. The primers were from chromosomes 1-5 and some included restrictive enzymes to create a clear polymorphism of the F2 progeny, to enable clear distinction of the heterozygous alleles.

Table 4 shows the lengths of each chromosome 1-5
Chromosome NumberLength (cM)Length (mb)113529.229717.5310123.6412522.2513926.2

Fig 4 shows a chromosomal map of the targeted loci for the available SSR microsatellite markers on each chromosome 1-5. This gives an indication of which markers to use to ensure each region of the chromosome is targeted.

Gel Electrophoresis
Agarose gels were made to show electrophoresis on the separate DNA strands. The agarose was tested at both 1.4 and 2.0 but 1.4 produced the best results. This consisted of 1.4g of agarose mixed with 100ml of TAE Buffer (40mM Tris-acetate pH 7.8 1mM EDTA pH 8) solution. This was melted and 3l of Ethidium Bromide was added and left to set in a gel tray containing the comb. After this was set TAE buffer was added and a further 3l of Ethidium Bromide. The gel was then left to run at 110V for 70 minutes in a twenty lane gel and for 45 minutes in a 10 lane gel. Chi squared was then calculated on each gel image to determine whether it had a 121 ratio or linkage.

AFLP
The PHD student collected plant material from a all resistant and all susceptible F2 plants. A DNA extraction was performed to gain DNA from resistant and susceptible plants. This was then cut up the DNA with restriction enzymes Mse1 and Pst1. It was then radio labelled with the Pst primer and and further un-labelled with Mse primer. It was then put through PCR which produced various fragments of different sizes. They were then run on a Urea gel, and left to expose a film. Once the film and had identified polymorphisms within the DNA, it was sequenced out of the gel and resuspended in water. This was then sent off to the John Innes Centre for sequencing.

RESULTS
Polymorphisms of the Test Markers for each Chromosome

Non-targeted SSR analysis
SSR microsatellite markers were analysed that are located on chromosomes 1-5. The DNA preps were used on Sna-s-BMYV, Col-S-BMYV and the F1 plant for each marker to determine the polymorphism.

Fig 5 shows col, Sna-1 and F1s tested on various SSR primers from each chromosome. From using the previous chromosome map it was possible to pick 3 primers which target different regions of the chromosome. Chromosome 5 lane 1-3 is NGA 106 (Col, sna-1 and F1). Lane 3-6 (col, sna, F1) was CA 72 from chromosome 5. Lane 6-9 was NGA 76. Chromosome 4 was NGA 8 (lane 1-3), NGA 12 (lane 4-6) and DHS1(lane 7-9) of which the latter showed very little polymorphism. Chromosome 3 used NGA 162 (lane 1-3), NGA 6 (lane 4-6) and NGA 172 (lane 7-9). Chromosome 2 was CIW3 (lane 1-3), CIW 2 (lane 4-6)and NGA 1126,. Chromosome 1 used NGA 111, NGA 128 and finally NGA 248.

The microsatellite markers varied in the amount of polymorphism they expressed however it was shown in chromosome 5 to have the greatest polymorphism in NGA 106 which showed approximately a 33 base pair difference between Col and Sna-1. From this it was possible to select those which had shown the greatest polymorphism from each chromosome and then test it on the DNA from the F2 progeny from the F1 plant crosses.

Table 5 shows each microsatellite marker and the results of the region they produced the bands Col-0 and Sna-1.
Microsatellite MarkerChromosome NumberPolymorphism in Col and Sna-1Col-0 length
(bp)Sna-1 length
(bp)NGA 1111Yes111103NGA 2481Yes143150NGA 1281Yes180175CIW 22No105105CIW 32Yes230210BIO 22Yes141151NGA 1723Yes162186NGA 1623Yes107115NGA 63Yes143119NGA 124No247--NGA 84No154--DHS14No----NGA 765Yes231253CA 725Yes124120NGA 1065Yes157135

Microsatellite Analysis
The microsatellite analysis initially proved unsuccessful in finding any specific linkage of Sna-1 however it did give good polymorphic images. The microsatellite markers chosen identified that the F1 generation was a genuine cross and both Col and Sna-1 bands were present in each lane. This was also determined in the F2 progeny which produced 121 ratios with homozygous and heterozygous alleles.

Chromosome 5 Gel images
The marker NGA 106 produced the best polymorphism and showed clear distinction between the two bands and produced clear heterozygote bands in both the F1 and F2 generation.
Figure 6 Before sequencing NGA 106 was used on chromosome 5 shows no linkage i.e. 121    ratio. The key gives the source in the lanes of the gel.

Fig 6 shows the microsatellite gel image for NGA 106 with Col, Sna-1 and het alleles. Lane 1 shows a 1kb marker, lane 2-4 shows Col, Sna-1 and F1 with clear polymorphism. Lane 5-20 contain the F2 generation. Col homozygous bands present in (F2-72R, F2-76R, F2-29R, F2-126R). Sna-1 homozygous bands present in (F2-131R, F2-43R, F2-78R, F2-127R). Heterozygous bands present in (F2-179R, F2-186R, F2-42R, F2-139R, F2-129R, F2-25R, F2-102R)

The gel image from fig 6 shows that through DNA extraction from plants with Col and Sna-1 and the F1 generation had adequate amounts of DNA to try and map the chromosomes after amplifying. From this it was possible to put the DNA under PCR and amplify the relevant strands. It is clear that the F1 generation produced true crosses and had not just self-fertilised and the same can be said for the F2 generation. The Col bands appeared around 135 and the Sna-1 bands occurred at 157, according to fig 6. Unfortunately, results from areas like lane 10 where the image is not clear is due to poor absorption of the Ethidium Bromide, however it was still possible to score this result.

There are fifteen samples of which four are Columbia and 4 Sna-1 with a further seven producing heterozygous results. Chi squared produced a 121 ratio so no linkage was detected.

When compared to other markers we can clearly see to the extent the clarity of the polymorphism. Fig 6 shows no polymorphism from NGA 172 from chromosome 3 as is shown in the gel image.


Fig 7 shows the PCR gel electrophoresis image produced from NGA 172. Lane 2-4 Col, Sna, F1. Lane 5-19 shows the F2 plants. Col-0 was seen in bands (F2-78R, F2-42R, F2-129R). Sna-1 homozygous bands present in (F2-179R, F2-168R, F2-76R, F2-127R). Heterozygous bands were seen in (F2-131R,  F2-43R, F2-78R, F2-139R, F2-72R, F2-76R, F2-126R, F2-197R).
The result from fig 7 makes scoring of the result unreliable, however in this case it was just about possible. For other results which produced unreliable results they were run on longer gels, such as CIW3 from chromosome 2. This was run on a 20 lane gel for a longer period of time to separate the bands clearly.

Fig 8 shows gel image from CIW3 from chromosome2 and shows clear polymorphism. Lane 1 is the 1kb marker lane 2-4 shows col, sna-1, F1. Lane 5-20 shows the F2 generation. Col-0 homozygous bands were present in plants (F2-197R, F2-131R, F2-78R). Sna-1 bands were present in (F2-168R, F2-42R, F2-76R, F2-179R, F2-102R). Heterozygous bands were present in plants (F2-43R, F2-25R, F2-127R, F2-129R, F2-29R, F2-72R, F2-126R,   F2-168, F2-43, F2 25, F2 42, F2 127, F2 197, F2 76, F2 131, F2 179, F2 102, F2 129, F2 29, F2 72, F2 78, F2 126, F2 139R).

Once every available marker had been used to target regions of chromosome 1-5, they were scored and the chi-squared was calculated to determine whether it showed a 121 ratio or segregation distortion, towards the resistant plant Sna-1.
The Chi square test  will establish whether the observed numbers of phenotypes  deviate significantly from those expected in case of independent assortment.

Table 6 Chi-squared Analysis of each Chromosomal Marker of Sna-1 (), Col-0 (--) and F1 (-)
MarkerChromosome -- -Chi ValueAllele RatioNGA 11115640.7332121NGA 24811212.5121NGA 12811211.85121ANTHATPASE13380.6121CIW 323580.5121BIO 223790.6121NGA 633390.6121NGA 17234370.142121NGA 16233570.86626121NGA 84NGA 124DHS14NGA 10654470.998121NGA 7654470.0998121CA 7253380.6121

After unsuccessfully scoring 15 primers with the F2 DNA progeny which produced the most DNA, there was no successful linkage found toward the Sna-1 ecotype. However after successful sequencing of the susceptible and resistant DNA from Col-0 and Sna-1 plant ecotypes a possible resistant region was discovered on chromosome 4 in the region 7533850-106182901bp. At the time the only available primers were G4539 which was tested on the region of 1589139 - 1589703 bp on chromosome 4.

Fig 9 G4359 caps marker with restriction enzyme Hind111. Lane 1-3 old extracted Col-0, Sna-1, F1. Lane 4-5 new extracted Col-0 and Sna-1. This marker does not show adequate polymorphism.

Fig 10 G4539 caps marker from chromosome 4 with restriction enzyme RSA1. Lane 1-3 Col-0, Sna-1 and F1. Lane 4-5 New extracted Col-0 and Sna-1. Shows clear polymorphism between both bands, with visible bands on the F1 progeny.
After successfully producing a restriction enzyme which cuts the DNA at a region producing clear polymorphism was then for a full microsatellite analysis used on the full F2 generation progeny, as shown in fig 8.

Microsatellite Analysis of F2 Progeny using G4539  RSA 1
Fig 11 G4539 with RSA1 used on the full F2 DNA progeny. 1 shows Lane 2-4 Col-0, Sna-1, F1. Lane 5-20 F2 29, F2 179, F2 76, F2 168, F2 225, F2 25, F2 45, F2 204, F2 166, F2 102, F2 127, F2 43, F2 93, F2 42, F2 72. Gel image 2 shows lane 2-4 Col-0, Sna-1 38, F2 129, F2 131, F2 173, F2 101, F2 37, F2 53, F2 115, F2 103, F2 139, F2 135, F 4, F2 7, F2 5, F2 159, F2 226. Gel image 3 shows F2 114, F2 126, F2 64, F2 82, F2 178, F2 182, F2 209, F2 197, F2 228, F2 152, F2 149, F2 66, F2 11, F2 12, F2 196

Two heterozygous plants were present in F2-103 and F2-114 progeny. The rest which were possible to score were Sna-0 bands.

Unfortunately the results produced poor images even after staining with further Ethidium Bromide. The procedure was also repeated with further incubation time for the restriction enzyme to digest, with no avail. Although it is clear to see that from the gel images that there is linkage to the Sna-1 resistance gene. It was possible to determine that 27 were homozygous for the Sna-1 allele 8 were heterozygous.

A further primer was needed to generate a genetic map and locate the region at which the primers were targeting chromosome 4. This was provided by the John Innes Centre as the primer CIW6 which targets Columbia at a region of 0.162kp and G3883 which target the region of Columbia at 1.4kb.

Figure 10 AGI Map for chromosome 4 as obtained from TAIR

The primer G3883 proved unsuccessful at producing any polymorphism however CIW6 showed clear polymorphisms and clear linkage to Sna-1 as shown in fig 10.
Fig 12 Shows a gel image of PCR with CIW6 primer from chromosome 4. Lane 1-3 Col-1, Sna-0 and F1, F2 25, F2 131, F2 168, F2 179, F2 43. The F2 plants F2-25, F2-131, F2 168 and F2 179 show linkage towards the Sna-1 region. This produces a corrupt 121 ratio.

Micosatellite Analysis on F2 progeny using CIW6 Marker on Chromosome 4

Fig 13 Full Microsatellite analysis of CIW6 on 46 F2 DNA preps with six heterozygous plants (F2-43, F2-93, F2-103, F2-114, F2-166, F2-221).

Position of the Primers on Chromosome 4
Table 7 The heterozygous recombinant alleles from both CIW6 and G4539 markers
F2 PlantCIW6G453943H-93H-103HH114HH166H-221H-
Table 8 Total Progeny and phenotype for both CIW6 and G4539
HomologyCIW6G4539 RSA1Col-010Sna-14023Heterozygous61Recombination71
Table 7 and 8 suggests CIW6 shows recombination of 7cM and G4539 shows a recombination of 1cM. The two heterozygous plants 103 and 114 when used with both G4539 and CIW6 both appear as recombinants, however G4539 is not conclusive as the scoring from the polymorphism could not be used.

Discussion
The beet mild yellows virus (BMYV) causing Beet mild yellows disease in sugar beet has been a great cause of worry in agriculture. It is spread through aphids or Myzus persicae and causes premature yellowing of leaves and hence lessened rate of photosynthetic activity. This not only affects the sugar content of the plant, the leaves are rendered useless as fodder.

This project was conducted to inspire work on preventing this debilitating disease of the sugar beet crop and prevent the loss in economy caused by the BMY virus. Much work has been done on viruses affecting other crops like the tobacco mosaic virus, cucumber mosaic virus. However, as has been shown earlier, sugar beet is an important contributor towards our economy and is a major component in the production of bio-fuel for the benefit of future generations, the study of diseases and their pathogens on this important crop requires careful study. Other diseases on sugar beet like beet curly top virus, beet necrotic yellow vein virus and beet yellows virus have also been studied extensively. However, our main aim was to focus on the Beet Mild Yellows Virus as this virus has also been a major hindrance towards effectively increasing the output of the sugar beet crop in a year.

The experiment conducted was to isolate two strains of the model plant Arabidopsis thaliana where one would show resistance and the other susceptibility towards the BMYV. This was in continuance with previous research performed by other scientists, on the test crosses of Sna-1 and Col-0. We wished to determine the susceptibility of BMYV by using aphid transmission to infect plants and generating and studying a self fertilized F2 generation. The investigation yielded one mutated Columbia plant that showed definite susceptibility towards the disease and one from Sna-1 that showed a possible resistant gene. The purpose of this project was to continue previous research on the test crosses of Sna-1 and Col-0. The plants were selected for F2 progeny and the analysis was to detect linkage by defined SSR markers. Thus, we carried out the crossing of these two parents. The F2 results pointed out the presence of susceptible gene in 31 ratio to the resistant ecotype proving the susceptible gene to be dominant against the resistant gene. Hence the genotypes of the progeny can be concluded to be of SS, Ss, sS (susceptible) and ss (resistant) variety.

The scope of this experiment also permitted us to find evidence pointing towards linkage of the susceptible gene (S) for Beet Mild Yellows Virus. We used various markers on the five chromosomes to locate the target gene. Amplified fragment length polymorphism technique was used to create clear polymorphism to confirm linkage. In the initial part of the experiment, clear polymorphism was not confirmed, however, on chromosome 5 which was acted upon by the microsatellite marker, NGA 106 distinct polymorphism was exhibited with an almost 33bp difference between Col-0 and Sna-1 ecotypes. This enabled us to compare the results from the F2 progenies with the chromosomes showing polymorphism. As was expected the marker, NGA 106, produced distinct heterozygous bands in both the F1 and F2 generation.

The primer NGA 106 an SSLP type marker used as PCR primer made to act on chromosome 5 with sequences TGCCCCATTTTGTTCTTCTC and GTTATGGAGTTTCTAGGGCACG (Name 2010) exhibited the most clear results on the full F2 generation. It was clear that F2 generation had two distinct clear bands on the agarose gel image, making it possible for clear scoring of the parent plants Sna-1 (ss), Col-0 (SS) as well as recombinants (Ss). Using all of the available primers it became apparent that successful 121 ratio was present in the F2 progeny.

After successful sequencing of the susceptible and resistant DNA from Col-0 and Sna-1 plant ecotypes a possible resistant region was discovered on chromosome 4 in the region of 7533850-106182901bp. We used SSLP with markers for specific regions to target the resistant area. The marker CIW6, provided by John Innes Centre, proved successful and showed distinct linkage to Sna-1. The results indicate a 7cM recombination which gives an idea of the distance from the gene however it requires the use of another marker to measure the amount of recombinants present and to detect which side of BMYV-s-Sna-1 it targets.

The marker G4539, to which restriction enzyme Rsa1 digest was added in PCR, did not show a 121 ratio. However, it also did not produce adequate results to map the chromosome.

However, it did not produce adequate results to map the gene.  To locate this marker in correlation to BMYV-ss-Sna-1 it needed to be flanked by markers mi260 9076497 - 9077409 bp. Perhaps more focus put through better staining of the fragments. Bowers et al (1996) suggests that silver staining is a more reliable method than automated fluorescence methods. It was found that while SSR amplification maybe analyzed by ethidium bromide using agarose gels, the allele size cannot be reliably estimated by this method and small size differences cannot be resolved as they can in acrylamide sequencing gels (Bowers et al, 1996). Allele size difference and clarity is determined by 1-2bp (Thomas et al, 1994).

Although from the available data, it appears that G4539 is slightly closer as it shows less recombination, it remains to be confirmed with the use of other markers to flank this marker in respect to BMYV-s-Sna-1. The two markers did prove that they were present on the same side of the gene along chromosome 4, which eliminates the possibility that they were on different sides of the resistant gene. This is because the two recombinant plants F2-103R and F2-114R both appeared as heterozygous. The two possible e scenarios are mapped as follows

Fig 14. The two markers linked to the BMYV-ss region mapped using Arabidopsis thaliana. Two possible outcomes were obtained, however further markers must be used to gain the exact loci position.

This implies that when crossing over takes place in Col-0 and Sna-1, the sites for G4539 and CIW6 are inherited together and therefore show linkage. With the use of other markers to flank these sites we should be able to zero in on the site at which the resistant gene may be present. This information could prove valuable for combining sources of resistance and to study whether resistance genes are alleles or situated at different loci along chromosome 4.  Unfortunately, due to lack of time we could not repeat the results with G4539 and RSA and hence could not predict its exact position on chromosome 4, however, if we pursue this experiment, whenever time permits, we should be able to score progenies of both plants and come out with clear results of heterozygote. As given in figure 10, the sites of CIW6 and G4539 are marked according to our estimates, which show that they act at close proximities and hence linkage is possible.

There have been other studies done on this particular disease but we wanted to determine for ourselves, which those sites are that contain the mutant resistant gene. The future prospect for this study is to achieve sugar beet plants that have been genetically modified to possess the resistant gene to overcome this viral infection.  Some of the work done on Arabidopsis in this field are sequencing and cloning of BMYV in pLitmus 29 and inserting the full-length capped RNA transcripts in Arabidopsis thaliana using electroporation. For this purpose the BMYV sequence had to be modified with DNA encoding jellyfish green fluorescent protein (GFP) at 3 end of P5 gene. The results showed up to 2 fluorescence. (Stevens  Vigano 2006).The progress made in this line is crucial to understand the properties of the virus and ways to overcome the disease.

Techniques used for routine detection of plant viruses
The techniques most commonly used to detect virus infection in plants are using enzyme labelled antibodies or amplification of viral genome by PCR or nucleic acid amplification techniques. However, molecular and serological techniques are fast becoming popular as the results are obtained in a very short time, in confined space without propagating the pathogens. Enzyme-linked immunosorbent assay or ELISA test and DAS ELISA (double antibody sandwich) are now being used to detect plant viruses. Virus particles get trapped by specific antibodies on the surface of wells during culture of the sap extracts. These are detected easily by enzyme-labelled antibodies that convert the substrate into brightly coloured pigments on the plates that are easily detected by the naked eye (Koenig 1981)

The beet mild yellows virus has a genome with six large open reading frames (ORFs) located on a single-stranded positive-sense RNA. The infection mostly remains localised in the vascular tissues. (Stephan  Maiss 2006)

Similar studies have proved successful such as that for Rhizomania which is formed through the virus necrotic yellow vein virus (BNYN). Families for resistance to rhizomania were discovered by crossing resistant and susceptible and inoculating them. Barzen et al (1997) then used molecular markers to combine sources of resistance to study whether resistance genes are alleles or whether they are situated at different loci. This proved successful as markers found to be linked to Rhizomania resistance to show resistance in B. vulgaris sub-species and in the commercial hybrid Golf indicating the possible existence of identical loci in these accessions.

In conjunction to the relevance with sugar beet most mapping has been based upon RFLP and RAPD markers on the nine linkage groups of B. Vulgaris (Schondelmaler et al, 1995). Until now only a few have combined different mapping techniques and furthermore most linkage maps do not establish the relationship between observed linkage and actual chromosomes (Schumacher et al, 1997). For the first time each of the linkage groups could unequivocally be assigned to one of the sugar beet chromosomes using SSR (). This had been based upon correlations between the karyotype of B.vulgaris chromosomes with all published linkage groups, and on the linkage relations with respect to mutants and molecular markers.

The application of marker-assisted selection within breeding programs for virus is as yet still limited, due to the lack of co-ordinated markers associated with BMYV resistant genes. The successful application of marker-assisted selection for virus resistence will be dependent on access to easily applied markers with close linkage to resistance genes. Previous markers have been developed for Ry (Hamalainen et al, 1997 Kasai et al, 2000) and for PVS the major resistance gene (Marczewki et al, 2002) and for the Rx PVX resistance gene (Bendahmane et al, 1997 De Jong et, 1997).

There are considerable variations in host ranges and serological reactions which have been shown to exist between members of the luteoviruses (Russel, 1965). BMYV and BWYV were considered to be strains of the same virus (Casper, 1988), even though they fed upon variable host ranges. It wasnt until the complete nucleotide sequence had been determined for BMYV previously by Guilley et al (1995) that it was discovered that BMYV should be considered a distinct virus rather than a strain of BWYV (Beet Western Yellows Virus). The nucleotide sequence of the genomic RNA of BMYV consists of 5722 nucleotides and six long open reading frames which conform to the arrangement characteristic if subgroup 2 luteoviruses (Guilley et al, 1995). Comparative analysis of complete genome sequences from BWYV and BMYV showed that BMYV is indeed a recombinant between two poleoviruses.

Little is currently known about the field strains in the UK, although studies by Brooms Barn have identified BMYV-BB-NC which infects sugar beet but not C bursa-pastoris or M perfoliata (Stevens et al, 1994). Also a strain BYDV-PAV-IL-1 is used to identify BMYV in winged aphids migrating into sugar beet crops (Smith et al, 1991). Although it has also been proven that BYDV-PAV-IL-1 does not detect the resistant strain BMYV-BB-NC, suggesting that BYDV-PAV-IL-1 underestimates the number of virus carrying aphids and infected plants. Also recently a monoclonal antibody was produced, MAFF-24, which showed considerable increase in sensitivity for detecting BMYV. This antibody is now used throughout the UK however it cannot distinguish between BMYV and BWYV (Smith et al, 1995).

With the growing number of polymorphic SSR markers available for targeting susceptible and resistant regions this could allow the removal of specific sequences for breeding. It also enables new strains of viruses to be implicated such as the new strain of Rhizomania which can now overcome the resistant variety. Research from Brooms Barn is now targeting this new strain with previous markers. To build up archive knowledge of polymorphic markers is crucial in the battle against crop pathogens.

Hence, our experiment with finding the linkage of the recessive resistant gene with a suitable marker is a step towards better understanding the disease. Our study will definitely be needed in future when the exact locus of the resistant gene is to be located. Other markers are needed to flank the loci, which was beyond the scope of our study. Thus, we have covered a significant portion in proving that the resistant gene does display linkage and it is my belief that we shall, very soon be able to carry our project to a new level.