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Discussion of a familial cross using two traits

In human beings, the gene for red green colorblindness (r) is sex linked and recessive to its allele for normal vision (R), while the gene for freckles (F) is autosomal and dominant over its allele for nonfreckled (f). A nonfreckled, normal visioned woman whose father was freckled and colorblind, marries a freckled, colorblind man whose mother was nonfreckled.

a. What is the genotype of the woman's father?
b. What is the probability that the couple's first child will be a non-freckled, normal visioned girl
c. What is the probability that the first two girls born to the couple will be freckled and colorblind?
d. What is the probability that the first child born to the couple will either be a freckled, colorblind boy or a non freckled, normal visioned girl or a non-freckled, normal visioned boy
e. What is the probability that the first four girls born to the couple will be freckled and normal visioned?

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I hope this explanation helps you with your studies.

So, this is a special case, since you have two traits ...

Solution Summary

In this solution, I discuss how to determine the outcomes of a two trait cross, one trait being autosomal the other sex-linked. Punnett squares and probability calculations are included.

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