The signal from R7 that induces Rh5 expression in R8 is as yet unknown. What ommatidial phenotypes would be expected of a loss-of-function mutant for the gene encoding this signal?
A) All R7 cells would express Rh3.
B) All R7 cells would express Rh4.
C) All R8 cells would express Rh5.
D) All R8 cells would express Rh6.
E) Both b and d

Question

Quizplus · Accepted Answer

Loss of the signal would exhibit the same phenotype the loss of R7 cells, resulting in all R8 cells expressing Rh6. However, this should have no effect on the stochastic distribution of Rh3 vs. Rh4 in R7 cells.

The Signal from R7 That Induces Rh5 Expression in R8