5 Certain recessive genes cause profound deafness and indivi

5. Certain recessive genes cause profound deafness, and individuals homozygous for such genes are occasionally found in high frequencies among extended families in small, isolated communities. A deaf man and a deaf woman from two different communities, each having deaf parents, had three children, all of whom had normal hearing.

A. What are the parental genotypes? (2 points)

What conclusions can be made about the allelic and gene interactions? (2 points)

Solution

The parental genotypes are either a/a; B/B or A/A; b/b

The allelic interactions include allele A is completely dominant to allele a. Allele B is completely dominant to allele b. The gene interaction exhibited by the trait is complentary gene action or the genes complement each other and both the alleles exhibit a different expression than the expression given by individual allele.