The results of our eye chromatography experiment confirmed that there are 2 gene

Question

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.

1. 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!

2. 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!

3. 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)?

4. 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

Note: eye colour is controlled by recessive alleles

Le’s say E1 E3 are dominant alleles for enzyme 1 and 3

e1e1 (white)

e3e3 (sepia)

e1e1E3e3 (white): no dominant allele for e1 while e3 has atleast one dominant allele

3. e3e3E1E1 (sepia): no dominant allele for e3 while e1 has both dominant allele

e3e3E1e1 (sepia): no dominant allele for e3 while e1 has atleast one dominant allele

4.Probably, the genes are interacting. Suppose E1 produces A product which has colour X and E3 produces an enzyme which converts product A to B of different color say Y. Presence of recessive alleles in homozygous conditions will not produce any functional enzyme. You can say in other words that the enzyme product of E1 is starting material for E3.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.