Platyfish with spots have an X-linked gene that produces the spots.All platyfish have an autosomal repressor that inhibits the expression of the spot-producing gene.The closely related swordtail lacks both the spot-producing gene and the repressor.In backcrosses between these two species, some hybrids receive the spot-producing gene, but not the repressor.These hybrid individuals should have reduced viability because they often develop malignant tumors due to improper regulation of the expression of the spot-producing gene.What can we conclude?
A) The ancestor of these fish likely had the spot-producing gene without the repressor.
B) This scenario is inconsistent with the Dobzhansky-Muller model.
C) Hybrids with the repressor, but not the spot-producing gene, should have high viability.
D) Reinforcement is likely to occur.
E) An adaptive radiation will likely occur.

Question

Quizplus · Accepted Answer

The autosomal repressor is what prevents the spot-producing gene from being expressed in all platyfish. It is likely that hybrids with the repressor will not have issues with tumor development because the expression of the spot-producing gene will be inhibited.

Platyfish with Spots Have an X-Linked Gene That Produces the Spots.All