Question

A species of beetle expresses a pigment protein as an adult but not as a juvenile. The pigment is encoded by the gene PIG. A protein called KID, which is only present in juveniles, is a transcription factor that binds to the DNA near the protein-coding sequence for PIG. Do you think KID is a negative regulator of PIG or a positive regulator? Why?

Some individuals in the species never express the pigment (neither as a juvenile or as an adult). Do you think they have a mutation in the KID gene, the KID binding site, or in the protein-coding part of the PIG gene? Why? (the ‘why’ part of the question will only be used to help us give possible credit for answers different than what we think is the clearest answer)

Answer 1

The KID protein is responsible for the no pigmentation at the juvenile stage. When the KID protein inhibits in the adult state, the pigmentation occurs in the body. This might occur because the KID protein acts as the repressor molecule and acts as a negative regulator of PIG protein.

The KID protein is responsible for pigmentation an adult stage. Any mutation in the KID gene might result in the loss of pigmentation in the adult. The KID gene is responsible for the binding of the KID protein and mutation in this gene can lead to the arrest of KID protein. The protein is unable to release and PIG continuously repressed in the adults.