Question

In Drosophila, yellow body is due to an X-linked gene (Xy) that is recessive to the gene for gray body (X+). A yellow female is crossed with a gray male. The F1 females are backcrossed with gray males. What proportion of the F2 progeny will be gray?

Answer 1

The F2 progeny will have a 1:1 ratio of gray to yellow body color.

Step-by-step explanation:

The proportion of gray progeny in the F2 generation can be determined using the principles of Mendelian genetics. Since yellow body color is a recessive trait, it can only be expressed in individuals with two copies of the recessive allele (Xy). The F1 females are heterozygous for body color (Xy/X+), and when they are crossed with gray males (X+/X+), the resulting F2 generation will have a ratio of 1:1 for gray to yellow body color.