Question

From the marriage of a deaf-mute woman with a normal man, a deaf-mute child was born. Determine the genotype of the parents.

Answer 1

Mother is homozygous, as congenital deafness is a recessive 

attribute. The genotype of the father can be either ВВ or Вb: in 

both cases he will be healthy. But the child was born ill, so, one 

recessive gene he had received from the mother, and another one 

he should receive from the father. The genotype of the father — 

Bb. 

The genotype of the mother is вв, the genotype of the father is Bb.