Question

In a normal fruit fly, the second thoracic segment has wings and the third thoracic segment has halteres (small knobbed structures that act as a balance and guidance system). The fruit fly shown below is a mutant in which the third thoracic segment produces wings instead of halteres. This abnormal fly has a mutation in which of the following?

A. a maternal effect gene
B. a gap gene
C. a homeotic gene
D. a segment polarity gene

Answer 1

C. a homeotic gene. The mutant fruit fly in question has a mutation in a homeotic gene, which controls the development of body segments and structures.

Step-by-step explanation:

The abnormal fruit fly in question has a mutation in a homeotic gene. Homeotic genes are responsible for controlling the development of body segments and the structures associated with them. In fruit flies, the Hox genes are a cluster of homeotic genes that determine the anterior-posterior body plan. Mutations in these genes can lead to the development of abnormal structures or the transformation of one structure into another.

In the case of the mutant fruit fly, the mutation in the homeotic gene results in the transformation of the third thoracic segment, which would normally have halteres, into a segment that produces wings instead. This change in structure is a result of the homeotic gene mutation.