Question

In human beings, a recessive X-linked mutation, g, causes green-defective color vision; the wild-type allele, G, causes normal color vision. A man and a woman (generation I), both with normal vision, have three children (generation II): a color-defective son, a daughter with normal vision, and a daughter with normal vision. In generation III , give the most likely genotypes for III-1. Assume anyone who married into the family does NOT have a history of this disorder.

Answer 1

Answer:

Gen 3          XGXg    XGY

Explanation:

In human beings, a recessive X-linked mutation, g, causes green-defective color vision; the wild-type allele, G, causes normal color vision.

Gen 1          XGXg     x     XGY

Gen 2            XgY  XGXG or XGXg

            Between XgY and anyone with no history of the disorder

                   XgY   x  XGXG

Gen 3          XGXg    XGY