A Rare,curly Winged Mutant of Drosophila Was Found in Nature $\times$

question 38

Multiple Choice

A rare,curly winged mutant of Drosophila was found in nature.A mating of this fly with a true-breeding,normal laboratory stock produced progeny in the ratio 1 curly winged to 1 normal (both sexes had the same ratio) .All curly winged progeny of this cross,mated with normal progeny of the same cross,again yielded 1 curly winged to 1 normal fly.When mated with one another,the curly winged progeny of the first cross yielded a progeny of 623 curly : 323 normal.This ratio strongly suggests which of the following?

• A)Curly and normal are in the 3:1 ratio expected from intercrossing monohybrid genotypes for a recessive mutant allele (curly).
• B)Curly and normal are in the 3:1 ratio expected from intercrossing monohybrid genotypes for a dominant mutant allele (curly).
• C)The curly winged parent of the curly \(\times\) curly cross is homozygous.
• D)Flies homozygous for the curly allele are lethal and never survive.
• E)The gene for curly is sex-linked.