Question

In cats, the gene for fur color is X-linked and there are 2 alleles, orange and black. The tortoiseshell pattern of black and orange patches is created due to X-inactivation in a heterozygote. A litter of kittens is born with 2 tortoiseshell females and 2 orange males. Of the choices below, which could be the phenotypes of their parents?

the correct answer is C , please show work and explain thank you.

a)	The mother is orange and the father is tortoiseshell.
b)	Both the mother and father are black.
c)	The mother is orange and the father is black.
d)	The mother is black and the father is orange.

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Answer 1

ANSWER is c) because in cat the dominate O allele of the X linded orange gene required to produce orange fur,and recessive o allele of this gene produce black fur.

so that the heterozygous Oo female cat have a tortoiseshell coat then in some patches of cell the chromosome with the O allele inactivated so the coat is black which determine o allele.in other patches of the cell the chromosome with the o allele inactivated so fur is orange since the O allele is active .

(orange female xblack male)OOXoY=Oo,OY,Oo,OY