Question

A geneticist is studying a particular Drosophila mutant that produces a phenotype of "no wing" due to a

mutation in a gene called wingless. She takes the mutant wingless and mutagenizes it. She hypothesizes that any
fly that emerges with wings will be due to the original mutated gene reverting back to the wild-type allele.
From this study, she identifies a fly that now has wings. When she sequences the wingless gene, she discovers
that the original mutation is still there, and there are no other mutations in the wingless gene. However, a second
gene at a separate locus is mutated. The second mutation is best classified as a(n) ________.
A) null mutation
B) intragenic suppressor mutation
C) conditional mutation
D) intergenic suppressor mutation
E) haploinsufficiency mutation

Answer 1

The second gene mutation is best classified as an intergenic suppressor mutation.

Step-by-step explanation:

The second gene mutation in this scenario is best classified as an intergenic suppressor mutation.

An intergenic suppressor mutation occurs when a mutation in a second gene at a separate locus compensates for the effects of a mutation in another gene, allowing the phenotype to revert back to the wild-type.

In this case, the original mutation in the wingless gene causes the fly to have no wings. However, the second gene mutation compensates for this and allows the fly to develop wings despite the presence of the original mutation in the wingless gene.