Question

Receptor tyrosine kinase signaling is important for photoreceptor development in the fly eye. When signaling is normal, the R7 photoreceptor develops normally. When signaling is impaired, no R7 cell is made.

a) You isolate mutations that prevent dimerization of the receptor. What happens to the fly eye in these mutants?

b) You next isolate a second mutation in the same fly that activates Raf. What happens to the fly eye in flies that have both of these mutations?

Answer 1

Please find the answers below:

Answer 1: According to the information, the functional protein is necessary for the appropriate development of the eye. A protein is required to be folded specifically to obtain the desired biological function from it. Since this mutant lacks one allele which prevents appropriate folding of protein, it will be developed with rudimentary eyes with improper or impaired function.

Answer 2: Raf is a cellular oncogenic protein which activates cancerous growth in cells. Hence, a fly with this mutation will tend to show tumor in occipital region. However, since the failure of dimerization of functional protein still exists, this fly too shall fail to develop functional eyes.