Answer:
=
Explanation:
Given that the woman’s maternal grandfather is color-blind, then it is possible that the woman is a carrier of color-blind allele.
Then probability that the woman is a carrier of color-blind allele is =
So if a carrier woman cross with a normal man
Let say the gene of the carrier woman is:
and the normal man =
so if we have a cross between and
; we have:
we can see the offspring to be :
=normal unaffected female
= normal unaffected male
= carrier female for color-blind
= carrier male for color-bind
Then probability that of inheriting defective allele = =
Let's not forget that the probability that the woman is a carrier of color-blind allele is =
∴ the probability that the son is colorblind =
=