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 ry41 Sb on one homolog and Ly ry564 on the other homolog, where ry41 and ry564 are two independently isolated alleles of 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 ry41. Out of 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 ry41 and ry564? |
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