If a gene in Drosophila is expressed only in imaginal disc (A) when it begins to differentiate, it is referred to as a homeotic gene. Recessive mutations in such genes often result in loss of function so that the structure does not develop. If a transgenic organism is made in which the gene is expressed in a different imaginal, disc (B), what is the predicted result?
A) deregulation of gene expression throughout disc A
B) loss of function of disc B's primary gene
C) gain of function of several inappropriate genes in disc A
D) deregulation of gene expression throughout disc B
E) gain of function in disc B of some of the structures usually seen in disc A

Question

Quizplus · Accepted Answer

Homeotic genes specify the identity of body parts during development. When a homeotic gene from one imaginal disc is expressed in a different disc, it can cause the second disc to develop structures characteristic of the first disc's identity, leading to a gain of function of those structures in the second disc.

If a Gene in Drosophila Is Expressed Only in Imaginal