BIOL 2153 Chapter : Snu6e Qp Ch05 Bcs
Document Summary
A male with singed bristles appeared in a culture of drosophila. Ans: the male-determining sperm carries a y chromosome; the female-determining sperm carries an x chromosome. Ans: cross the singed male to wild-type females, and then intercross the offspring. If the singed bristle phenotype is due to an x-linked mutation, approximately half the f2 males, but none of the f2 females, will show it. In grasshoppers, rosy body color is caused by a recessive mutation; the wild-type body color is green. Ans: all the daughters will be green and all the sons will be rosy. In the mosquito anopheles culicifacies, golden body (go) is a recessive x-linked mutation, and brown eyes (bw) is a recessive autosomal mutation. A homozygous xx female with golden body is mated to a homozygous xy male with brown eyes. Genotype (1/2) (1/4) = 1/8 go/go or y bw/bw go/go or y +/bw or + (1/2) (3/4) = 3/8 (1/2) (1/4) = 1/8.
