Question

Genes for body color (B black dominant to b yellow) and wing shape (C straight dominant to c curved) are located on the same chromosome in flies. If single mutants for each of these traits are crossed (yellow fly crossed to a curved wing fly), and their progeny is testcrossed, the following phenotypic ratios are observed among their progeny

Answer 1

The progeny resulting from a cross between a yellow fly and a curved wing fly, followed by a testcross, is expected to show a phenotypic ratio of 1 black, straight: 1 black, curved: 1 yellow, straight: 1 yellow, curved, assuming no gene linkage or crossing over.

Step-by-step explanation:

The question is about the phenotypic ratios observed in progeny resulting from a cross between a yellow fly and a curved wing fly, followed by a testcross. The genes for body color (B black dominant to b yellow) and wing shape (C straight dominant to c curved) are located on the same chromosome in flies. When single mutants for each of these traits are crossed, the predicted phenotypic ratios are 1 black, straight: 1 black, curved: 1 yellow, straight: 1 yellow, curved, assuming no gene linkage or crossing over.