Some forms of cataracts and deaf-dumbness in humans are autosomal recessive signs.

Some forms of cataracts and deaf-dumbness in humans are autosomal recessive signs. What is the probability of having healthy children in a family if the parents are diheterozygous?

Let’s designate the deaf-mute gene as a, the cataract gene as b, healthy alleles – A and B. The genotypes of both parents will be AaBb.

R: AaBb x AaBb – healthy parents, carriers of disease genes;

G: AB, Ab, ab, ab x AB, Ab, ab, ab – possible gametes;

F1: Let’s use a Pennett lattice for a dihybrid crossing. Analyzing the genotypes presented in it, we find the probability of having a healthy child: 9/16 or 56.25%.