1
$\begingroup$

I have a follow-up question about an in-lecture question (this is not a homework question). As you can see I have already answered the question and the question is closed to further submissions.

enter image description here

In any case, this is my reasoning.

The male has the genotype Gg and BB. Fur color is incompletely dominant so to have black fur this implies the male has the genotype BB not Bb (which would likely be gray).

The female has genotype Gg and Bb because as the question states, the female is doubly heterozygotic.

The two have a FEMALE offspring - this is critical. This means that the male "donates" a copy of his X chromosome to the offspring. Now if the question had asked about a male offspring, then that would mean the male had donated a copy of his Y chromosome instead, and the male would have no "say" in the male progeny's eye color.

So the probability of green eyes between a cross of Gg with Gg is 3/4.

The probability of black fur between a cross of BB and Bb is 1/2 given that there is incomplete dominance.

So the probability of both events occurring simultaneously is 3/4 * 1/2 = 3/8 = 0.375.

Is this correct? Or should I account for the "female" offspring part and half the answer?

$\endgroup$
2
$\begingroup$

The male has a phenotype XGY BB, and the female, XGXg Bb. Thus the probability is 0.25.

$\endgroup$
2
$\begingroup$

Eye color is sex-linked. So a green-eyed male has genotype G- (only one X chromosome) for eye color and BB for fur color. The female has genotype GgBb. For the offspring to be female, 1/2 probability, to have green eyes 1/1 probability (G is dominant and it will receive the G from the father), and for gray fur 1/2 (1/2 chance it will receive b from the mother). So 1/2 * 1/1 * 1/2 = 1/4

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.