Question: In Drosophila, the map positions of genes are given in map units numbering from one end of a chromosome to the other. The X chromosome of Drosophila is 66 m.u.. long. The X-linked gene for body color-with two alleles, y + for gray body and y for yellow body-resides at one end of the chromosome at map position 0.0. A nearby locus for eye color, with alleles w + for red eye and w for white eye, is located at map position 1.5. A third X-linked gene, controlling bristle form, with f + for normal bristles and f for forked bristles, is located at map position 56.7. Each gene resides on the X chromosome, and at each locus the wild-type allele is dominant over the mutant allele. Predict the frequency of yellow with white eyes and forked bristles progeny type produced by this mating.