The fruit fly cross shown here analyzes the transmission of two genes in the X chromosome. The male parent has mutant alleles for both the white gene (w^-) and the crossveinless gene (cv^-). The female parent has nonmutant forms of these genes (w⁺ and cw⁺). Use the figure below to answer the following question:
If an F₁ female resulting from this parental cross is crossed with any male, his Y-bearing sperm will allow the experimenter to determine distance between the w and cv genes by analyzing the phenotypes of the F₂ male progeny.

Question

Quizplus · Accepted Answer

The F₁ female resulting from the parental cross carries both mutant alleles for the w and cv genes on one X chromosome. When she is crossed with any male, the male progeny will receive either the mutant w or cv allele on their X chromosome from the female parent. If a male progeny ends up with the w and cv mutant alleles on the same X chromosome, they will exhibit the double mutant phenotype of white eyes and no crossvein. By analyzing the phenotypes of the male progeny resulting from this cross, the distance between the w and cv genes can be determined.

The Fruit Fly Cross Shown Here Analyzes the Transmission of Two