In a laboratory population of fruit flies, body color is determined by a single gene with a wild-type allele associated with black body color and a mutant allele associated with yellow body color. A group of researchers hypothesize that the mutation in fruit flies that causes the yellow body is sex-linked. They also hypothesize that this mutation results in a change in the structure of the sex combs, bristle-like-structures on the front legs of male flies that facilitate mating.