Question

What is the probability that a couple will have a type A child if the mother has Type
A blood and is heterozygous for the trait and the father has type AB blood?

Answer 1

Answer:

50%

Explanation:

To solve this, we'd need to use a Punnett square.  Since the mother has a heterozygous genotype and has an A-blood phenotype, we know that she is AO and the father is AB.

          A             B

A       AA           AB

O      AO           BO

According to this, the four possible blood types, with equal probability are: AA, AB, AO, and BO.  Both AA and AO genes will result in type-A blood, since A is dominant over O.  Therefore, there is a 2 in 4 (or 1 in 2, or 50%) chance of the child having type-A blood.