Genetics lab

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Sandy Yossef Comment by Elizabeth Jackson: Grade:-2 hypotheses-2 chromosome locations-2 mutant lines-1 citation formatting-1 missing lab manual and flybase sources-1 grammar/italics6/15

Genetics lab

BIOL 3251-010

Assignment 1

Drosophila melanogaster, the common fruit fly, is a well-known model organism used for genetic research. The laboratory exercise will aid in differentiating normal ‘wild type’ and various mutant phenotypes of the fruit fly. The laboratory exercise will help in developing an understanding of the connection between the presence and absence of genetic trait of the general fruit fly population. Comment by Elizabeth Jackson: Drosophila melanogasterItalicize scientific names.Also, you should start with a statement about genetic inheritance. Comment by Elizabeth Jackson: It is too early in the introduction to talk about your own project. Focus on background information first.

Genetic science has identified and documented over 2,500 species of Drosophila. Out of these numbers of Drosophila one specie; Drosophila melanogaster (Fruit fly) has been primarily exploited as a model for genetic research. The D. melanogaster is the most suitable model for genetic work because of its short life cycle. This species lives for about 10 to 11 days and its optimum survival temperature is 220 C (Wangler, Yamamoto & Bellen, 2015). Another primary model advantage is that D. melanogaster has high reproductive potential. The species reproduces a large number of progeny. Such a large number of progeny is required for statistical analysis of results (Wolf, & Rockman, 2008). The general characteristics of genetic model organisms include a short generation time, a large number of progeny and easy genetic manipulation. Comment by Elizabeth Jackson: You need a citation for this.

Genetic scientists still have numerous biological processes to discover. The D. melanogaster has many possibilities because this model can quickly and efficiently answer questions of biological phenomena (Wangler, Yamamoto & Bellen, 2015). The D. melanogaster is an excellent model because it has a translational impact for genetic disease and a large number of medical implications including vector-borne illnesses. Comment by Elizabeth Jackson: You need citations for sentences like this.

This laboratory will use a wild-type D. melanogaster. Both male and females will use. The two sexes are differentiated in ways of physical characteristics. For example, males have a sex comb, a fringe of black bristles on their forelegs (Wolf, & Rockman, 2008). The male’s abdomens are elongate and rounded in males, but characteristically pointed in females. The wild type is the naturally occurring fly with not mutation. Other mutant flies that are common in the laboratory during breeding and that needs to be isolated from the wild-type ebony mutants that exhibit a much darker body as compared to the wild type fly (Wolf, & Rockman, 2008). Other common mutants are referred to as white-eyed female, wild type heterozygote female, white-eyed male, and wild type male. Comment by Elizabeth Jackson: Did we use this as a method for sexing the flies? Comment by Elizabeth Jackson: We didn’t look at ebony mutants in this lab. Comment by Elizabeth Jackson: This sentence doesn’t really make sense. You say “other common mutants”, but then you mention wildtypes. By definition, wildtypes are the exact opposite of mutants.

Flies with shortened wings are referred to as having vestigial genes that occur in the second chromosome. The vestigial genes occur due to recessive vg allele that specifies short vestigial wings. The flies have a recessive mutation of vestigial genes that occur in the second chromosome for both parents (Wolf, & Rockman, 2008). Other flies exhibit curled wings resulting from curly genes that also occur in the second chromosome. The flies those are yellow than normal exhibit yellow genes resulting from mutations occurring in the X chromosome (Wolf, & Rockman, 2008). The dark bodied flies carry a defect in their eye resulting to flies with phenotypic ebony genes. The ebony genes occur in the third chromosome and are responsible for building up a tan-coloured pigment. Comment by Elizabeth Jackson: Did you use flybase for this? If so, you need a citation. Comment by Elizabeth Jackson: We didn’t look at curled wings.

Complete and incomplete linkages in D. melanogaster occur independently. For example, the grey body and the long wing phenotype of this fly dominate over the black body and vestigial wings characteristics. Crossing over of genes occurs in the first generation, but the phonotype does not continue to the second generation (Garud, Messer, Buzbas, & Petrov, 2015). However, if the cross-over continued to the next generation it could be referred to as a complete linkage. Complete linkage in D. melanogaster genes is a rarity among female phenotype, but is common among the male mutant phenotype. The male mutant genes are closely associated and always transmitted together.

Reference

Garud, N. R., Messer, P. W., Buzbas, E. O., & Petrov, D. A. (2015). Recent selective sweeps in North American Drosophila melanogaster show signatures of soft sweeps. PLoS genetics11(2), e1005004. Comment by Elizabeth Jackson: The first authors of your citations are correct, with their last names first, followed by their first and middle initials. The other authors should have their initials first, followed by their last names. Comment by Elizabeth Jackson: Drosophila melanogaster

Wolf, M. J., & Rockman, H. A. (2008). Drosophila melanogaster as a model system for the genetics of postnatal cardiac function. Drug Discovery Today: Disease Models5(3), 117-123.

Wangler, M. F., Yamamoto, S., & Bellen, H. J. (2015). Fruit flies in biomedical research. Genetics, genetics-114.