Essay on Examining the Crosses Between Drosophila Fruit Flies

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Examining the Crosses Between Drosophila Fruit Flies Introduction The major topic of this experiment was to examine two different crosses between Drosophila fruit flies and to determine how many flies of each phenotype were produced. Phenotype refers to an individual’s appearance, where as genotype refers to an individual’s genes. The basic law of genetics that was examined in this lab was formulated by a man often times called the “father of genetics,” Gregor Mendel. He determined that individuals have two alternate forms of a gene, referred to as two alleles. An individual can me homozygous dominant (two dominant alleles, AA), homozygous recessive, (two recessive alleles, aa), or heterozygous (one dominant and one recessive…show more content…
One was labeled ebony vs. vestigle and the other labeled white vs. wild. Heterozygous flies were placed in the ebony vs. vestigle vial, and flies with a genotype of XwXw (x) XwY were crossed in the white vs. wild. The second week of the experiment the heterozygous flies were removed from the vial before their offspring pupate. The same was done with the ebony vs. vestigle the parental flies were removed. Using flynap, which anesthetized the flies for up to 50 minutes without killing them, allowed for the flies to be removed. Two absorbent swabs were dipped in the flynap and then placed in the vials with the plugs still on the vials. The swabs were left in the vial for 2 to 4 minutes, and then the parental flies were removed. The offspring’s were left in the vials to pupate. During the third week the same procedure was performed on the offspring. In the ebony vs. vestigle vial the offspring were separated into normal bodies and normal wings, normal bodies and vestigle wings, ebony bodies and normal wings, and ebony body and vestigle wings. In the white vs. wild the offspring were separated into red eyed male, white eyed male, red eyed female, and white eyed female. The phenotype of the parental cross in the white vs. wild was white eyed females (x) red eyed males. The phenotype of the parental cross in the ebony vs. vestigle was ebony body color (x) normal body vestigle wings. The phenotype of the flies put in the F1
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