Question

In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?
A) tortoiseshell female; black male
B) black female; orange male
C) tortoiseshell female; tortoiseshell male

Answer 1

Answer:

A) tortoiseshell female; black male

Explanation:

Females have two X chromosomes and males have an X and a Y chromosome.

The possible genotypes and phenotypes are:

• XᵒXᵒ: black female
• XᵒY: black male
• XᴼXᴼ: orange female
• XᴼY: orange male
• XᵒXᴼ: tortoiseshell female

Cross of a black female and an orange male

XᵒXᵒ  x  XᴼY

The female only produces Xᵒ gametes. The male produces Xᴼ and Y.

The possible offspring therefore is:  XᵒXᴼ (tortoiseshell females) and XᵒY (black males). The answer is A.