Hearing in humans depends on the coordinated activity of several pairs of genes. Normal hearing develops

Hearing in humans depends on the coordinated activity of several pairs of genes. Normal hearing develops only if each of these genes has at least one dominant allele. If at least one pair of genes is a recessive homozygote, the person will be deaf. Suppose genes A and B form normal hearing. Can deaf parents have children with normal hearing? What are the genotypes of parents and children?

There are three options for solving this problem.

1. Both parents are homozygous for the second, dominant pair of traits.

R: AAbb x aaBB;

G: Ab x aB;

F: AaBb – 100% healthy.

2. Both parents are heterozygous for the second, dominant pair of traits.

R: Aabb x aaBb;

G: Ab, ab x ab, ab;

F: AaBb – 25% healthy;

Aabb – 25% deaf;

aaBb – 25% deaf;

aabb – 25% deaf.

3. One parent is homozygous, the second is heterozygous for the second pair of traits.

R: AAbb x aaBb;

G: Ab x aB, ab;

F: AaBb – 50% healthy;

Aavv – 50% deaf.