In the vinegar fly, the short wings (a) are recessive recessive with respect to the normal character, the long wings (A); and the gene for this wing-size trait is autosomal. In the same insect, the white color of the eyes (b) is produced by a recessive gene located on the X chromosome, with respect to the dominant red color (B).
A female, homozygous for both characters, with long wings and white eyes, is crossed with a male with long wings and red eyes, a descendant of a male with short wings.
a. Give the genotypes of the parents of the cross and their offspring.
b. What proportion of females will be heterozygous for the two characters?