Question

(b) in a mating involving a deaf man and a deaf woman (both heterozygous), could all the children have normal hearing? explain your answer.

biol 223 lab 3, 10 points your name__ date__

(c) another form of deafness is caused by a rare autosomal recessive gene. in a mating involving a deaf man and a deaf woman, could some of the children have normal hearing? explain your answer.

Explanation:

For part (b), let the allele for normal - hearing be \(A\) and the allele for deafness be \(a\). The parents are both heterozygous (\(Aa\)). Using a Punnett - square analysis, the possible genotypes of their offspring are \(AA:Aa:aa = 1:2:1\). Since \(AA\) and \(Aa\) genotypes result in normal - hearing (dominant allele \(A\) masks the recessive \(a\)), it is possible for all children to have normal hearing if, by chance, all inherit at least one dominant \(A\) allele.
For part (c), if deafness is caused by a rare autosomal recessive gene and both parents are deaf, they are likely to be homozygous recessive (\(aa\)). All of their offspring will inherit the recessive \(a\) allele from each parent, resulting in the \(aa\) genotype and deafness. So, it is not possible for their children to have normal hearing.

Answer:

(b) Yes. The parents are heterozygous (\(Aa\)). Offspring genotypes can be \(AA\), \(Aa\), or \(aa\). If all inherit \(A\) (either \(AA\) or \(Aa\)), they will have normal hearing.
(c) No. Since both parents are likely homozygous recessive (\(aa\)), all offspring will be \(aa\) and deaf.