Question

Drosophila (fruit flies) usually have long wings ( ), but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg). If a homozygous bent wing fly is mated with a homozygous vestigial wing fly, which of the following offspring would you expect?

a. All +bt +vg heterozygotes
b. 1/2 bent and 1/2 vestigial flies
c. All homozygous + flies
d. 3/4 bent to 1/4 vestigial ratio
e. 1/2 bent and vestigial to 1/2 normal

Answer 1

Answer:

all +bt +vg heterozygotes.

Explanation:

The mutation changes the chromosome structure or might change the gene sequence of the organisms. The mutation might result in the defective phenotype.

The mutation in Drosophila wings causes  bent wings (bt) or vestigial wings (vg). The homozygous bent wing (+bt +bt) are crossed with homozygous vestigial wings ( +vg+vg). Their cross is as follows:

parents : +bt +bt  and +vg+vg

Gametes:   +bt                   +vg

F1 cross:       +bt +vg.

Thus, the correct answer is option (a).