A very common type of red–green colorblindness in humans is caused by a mutation in a gene located on the X chromosome. Knowing
that the mutant allele is recessive to the wild type, what is the probability that the son of a woman whose father is colorblind is going to also be colorblind
According to the given information, the allele for the red-green colorblindness is inherited in an X linked recessive manner. Let's assume that the allele X^c is responsible for red-green colorblindness. The woman is normal but had a colorblind father (X^cY). Fathers give their X chromosomes to the daughters while their Y chromosome is transmitted to their sons. The sons get their X chromosomes from the mother.
The colorblind father has transmitted the X-linked allele for the red-green colorblindness to his daughter. Therefore, the genotype of the woman is X^cX. The woman would produce two types of eggs: 50 % with X^C and 50% with X. Therefore, 50% of sons of this woman would get X linked allele for the red-green colorblindness and would be affected by the disorder while the rest 50% of her sons will be normal.
Males would be more affected because they inherit only one X chromosome. Women would have to inherit two recessive genes to develop the trait, while men would have to inherit only one.
