Homework Clinic
Science Clinic => Biology => Topic started by: jon_i on Mar 26, 2020
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A certain type of congenital deafness in humans is caused by a rare autosomal (not X-linked) dominant gene.
(a) In a mating involving a deaf man and a deaf woman (both heterozygous), would you expect all the children to be deaf? Explain your answer.
(b) In a mating involving a deaf man and a deaf woman (both heterozygous), could all the children have normal hearing? Explain your answer.
(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.
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(a) No. In a mating involving heterozygotes, three genotypic classes are expected in the offspring: fully dominant, fully recessive, and heterozygous.
(b) Assuming that the parents are heterozygotes (because the gene is rare), it is possible that all of the children could have normal hearing.
(c) Because the gene in question is recessive, both of the parents are homozygous and one would not expect normal hearing in the offspring.