Drosophila Genetics Homework The results of our eye chromatography experiment co

ID: 65629 • Letter: D

Question

Drosophila Genetics Homework

The results of our eye chromatography experiment confirmed that there are 2 genes that control eye color in our strains of fruit flies. One gene codes for the presences of enzyme #1 and white eyed flies produce only a non-functional form of this enzyme. The other gene codes for enzyme #3, and sepia flies produce a non-function form this enzyme.

Let’s suppose that there are 2 alleles for each of the genes that code for each of the enzymes involved in fruit fly eye (one dominant, the other recessive). Also let’s assume for now that alleles that code for non-functional enzymes are recessive in each case. Based on this, what would be the predicted phenotype of a fruit fly that is heterozygous at each of the genes that you have proposed would affect eye color? Explain!

What would be the predicted phenotype of a fruit fly that is homozygous recessive at one of the genes that you have proposed would affect eye color (assume the fly is heterozygous or homozygous dominant at the other gene(s)? Explain!

What would be the predicted phenotype of a fruit fly that is homozygous recessive at the other gene that you have proposed affects eye color (again, assume the fly is heterozygous or homozygous dominant at the other gene(s)?

Do the genes interact in some way? Explain how using your knowledge of the relationship between genotype, the protein products of genes and the resulting phenotype.

Explanation / Answer

Based on the information given in the Question

White is recessive, so we will assign W1 for it.

Brown is dominant, so we will assign B1 for it.

Genotype

Phenotype

.w1w1B3B3

.w1w1B3b2

White

.W1W1b3b3

.W1w1b3b3

Brown

As stated in part 1, let us assume that allele’s code for the non functional enzymes are recessive in each case, and then the Genotypes will be W1w1B1b1 (heterozygous at each of the genes). This will affect the eye color and will have brown color eyes.

As stated in part 2, predict the phenotype of a fruit fly which is homozygous recessive at the other gene

.w1w1B3B3 and .w1w1B3b3 combinations will come if we assume that the fly is heterozygous or homozygous dominant at the other gene. Both the combinations will give white eyes.

.W1W1b3b3 and .W1w1b3b3 will give brown color eyes.