Problem:
A sex-linked recessive allele of a gene "c" produces red-green colour blindness in humans. A normal woman whose mother was colour-blind, marries a colour-blind man.
Required:
Question 1: What genotypes are possible for the mother of the colour-blind man??
Question 2: What is the chance that the first child from this marriage will be a normal seeing girl?
Question 3: Of all the boys produced by these parents, what proportion is expected to be colour-blind??
Question 4: Of all the children (sex unspecified) from these parents, what proportion is expected to be normal?