2:30-4:25 Wednesday Biology 1103 Lab Group: Wil BuchananWhitney Boozer2009-2010 TermC.elegans have been organisms in science known to uncover the many secrets of some of the most basic cellular processes in animals. Some of the uses of C.elegans in science include research onembryonic development, sex development, sex determination, aging, and alcoholism (laboratory manual, sixth ed.). Some reasoning behind the effectiveness of C.elegans in this research is their versatility. The species C.elegans are usually hermaphrodites meaning they make both eggs and sperm. Another unique aspect is their ability to reproduce by either self-fertilization or mating with a male. C.elegans are harmless round worms, but they can often be mistaken for vicious, bloodsucking parasites. When viewing C.elegans, some telltale characteristics one can look for is their long, slim physique with females differing in their feathered off wispy tail compared to the fat bulb of the male. The females, other known as hermaphrodites with their androgynous characteristics, often move slower than the males who speed swiftly under the lens of a high-powered microscope. There can be several types of C.elegans varying from mutant females, coupled with the wild-type males and females The male species is often seemingly outnumbered by the amount of females resulting from the female’s ability to self produce and mutate with various species. When establishing a cross between organisms, once must first consider many things. The projected outcome of the cross must be taken into account as well as the status of the organism, for example, whether it is mutated or normal. If mutated, it is also important to evaluate the source of the mutation assessing its dominance or recessiveness and deciphering whether the disease is sex-linked, resulting from the female chromosome, or from one of the other twenty-two autosomal chromosomes.When approaching our scientific cross, my lab partner and I aimed especially to further investigate mutations in C. elegans. Our first inquiry was to find out if the mutation in the hermaphrodite of question was sex-linked or autosomal. Sex-linked genes are the phenotypicexpression of an allele that is related to the chromosal sex of the individual. The most telltale sign in concluding if the gene is x-linked recessive or not is if the son has the defective gene resulting in a mutation. Because the gene is recessive, it is usually up to the son to detect the gene because he will pick up a defective x from the mother and a y from the father. Girls have the beneficial circumstance of having a backup “x” from the mother that often results in them not receiving the mutation. Autosomal recessive on the other hand depends on the genotype of both parents. Because of this, bothparents must be carrier’s for the gene in order for the mutation to be expressed in the offspring. A carrier simply means that each parent contains the recessive allele for the mutation. This usually does not mean that they have the mutation, only the fact that they have a strong chance of transferring the mutation to their offspring. XhX [Sex-linked] x XY XhX x XhY [Autosomal] VsFor our mutation, our group decided to pick a C-elegan known as dpy-5. Its characteristics differing from normal wild type worms are largely due to dpy-5’s short and fat physique. Initially, we projected that the mutation in question would be autosomal, and that the mutated dpy 5 contained the dominant allele. If this were to be the case, our cross of the mutated dpy 5 with a normal wild-type Xh Xh YXh Xh XhYX XhX XYXh X YXhX XhY X XX XYmale would produce one hundred percent mutated hermaphrodites since the trait was dominant over the recessive wild-type allele. Our projected cross: D: mutated allele x d: normal wild type allele D Dd Dd Dd d Dd DdKey: DD: mutated dpy 5 is dominant therefore results: 100% mutationAfter procuring two crosses to produce the most efficient results, we found the info to be much different from what we expected. This is the information we received.Cross 1 Mutated Male 0 Normal Wild typeMale24Mutated Hermaphrodite20 Normal Wild type Hermaphrodite57Cross 2 Mutated Male 0 Normal Wild typeMale21Mutated Hermaphrodite34 Normal Wild typeHermaphrodite49 From these results, we could infer that our entire initial hypothesis was proven false. Before the experiment, our group anticipated offspring that would reflect a dominant mutation and alloffspring would receive the mutated allele, but surprisingly enough, these expectations were mistaken. Based on these results, it is apparent that the dpy 5 allele is recessive. Because of this allele’s autosomal recessive characteristics, our experiment resulted in no mutated males and a plethora of wild-type male and hermaphrodites.When analyzing these results, we could conclude that the mutation was not sex-linked because none of the male received the mutation. Even though the male had the normal, healthy “y” chromosome, a defective “x” chromosome from the mother should have produced at least of few mutated males as a result. Essentially, we can also rule out the dominance of the allele because the offspring do not show a dominance of the mutation. We know from the data that none of the males displays this gene, but what about the hermaphrodites one may ask? Well we know that hermaphrodites are unique in stature. Unlike the normal males, they have the ability to produce eggs and sperm; as well as self-fertilize. Because of this knowledge, we can critically assess the information and expertly infer that the resulting mutated hermaphrodites occurred only because of their self-fertilization