Question

A child is born to a couple, one of whom is heterozygous for an autosomal dominant disease. the other parent is homozygous normal. what would be the child's chances of having the disease?

Answer 1

Let 'C' denote the autosome with the dominant gene and 'c' denote the normal gene. The genotype of the parent who is heterozyzous for the autosomal dominant disorder will be, Cc. The parent who is homozygous for the normal gene will have the 'cc' genotype. The cross between the two parents will lead to two copies of the Cc and cc genotypes (shown in the image). The progeny with the 'Cc' genotype will be affected with the disorder. The probability of getting the disorder turn out to be, 50% (2 out of 4).