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9. Albinism is a rare autosomal recessive disorder. Jane and Tom want to have ch

ID: 272422 • Letter: 9

Question

9. Albinism is a rare autosomal recessive disorder. Jane and Tom want to have children. While they are both phenotypically normal, they each have a history of albinism in their family. Jane's bother was albino and Tom's grandfather on his dad's side was also albino (draw out the pedigree first and then proceed to figure out the genotypes. On the quiz I might ask you some of the family member's possible genotypes) a. What is the chance that Jane and Tom have an albino child? b. What is the chance that Jane and Tom have a child that is a carrier for albinism (ie phenotypically normal, but carries an albino allele...Aa).

Explanation / Answer

Answer:

a). Based on the given description, both Jane and Tom would be heterozygous for albinism.

A_ = normal

aa = albino

Jane (Aa) x Tom (Aa)-------Parents

The probability that the child will be albino=1/4 or 25%

b). The probability that the child is carrier = 1/2 or 50%

A a A AA(normal) Aa( normal) a Aa (normal) aa ( albino)