The rosy (ry) gene of Drosophila encodes an enzyme called xanthine dehydrogenase. Flies homozygous for ry mutations exhibit a rosy eye color. Heterozygous females were made that had ry^41 Sb on one homolog and Ly ry^564 on the other homolog, where ry^41 and ry^564 are two independently isolated mutant alleles or ry. Ly [Lyra (narrow) wings] and Sb [Stubble (short) bristles] are dominant mutant alleles of genes to the left and right of ry, respectively. These females are now mated to males homozygous for ry^41. Out of the 100,000 progeny, 8 have wild-type eyes, Lyra wings, and Stubble bristles, while the remainder have rosy eyes.
a) What is the order of these two ry mutations relative to the flanking genes Ly and Sb?
b) What is the genetic distance separating ry^41 and ry^564?
