Question

what is the best evidence to prove that irene was heterozygous for hemophilia? elizabeth is not a carrier for the trait. tatiana carried the recessive allele. her brother has hemophilia and her sister is a carrier. two of her sons have hemophilia and one does not.

Explanation:

Hemophilia is an X - linked recessive disorder. If Irene is heterozygous (a carrier), she has one normal and one mutant allele. When she has sons, they inherit their X - chromosome from her. If two of her sons have hemophilia (received the mutant allele) and one does not (received the normal allele), it indicates she has both the normal and mutant alleles, making her heterozygous.

Answer:

D. Two of her sons have hemophilia and one does not.