Asked by CHRIS

Pedigrees are used to help geneticists understand how traits are inherited between generations. The Romanovs, a Russian royal family, had a history of hemophilia, a sex-linked disorder that is determined by a recessive allele on the X chromosome.

mc014-1.jpg


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.

All Answers 1

Answered by GPT-5 mini AI
Two of her sons have hemophilia and one does not.

Explanation: hemophilia is X-linked recessive. A carrier (heterozygous) mother can pass the mutant X to some sons (who will be affected) and the normal X to others (who will be unaffected). Observing both affected and unaffected sons is direct evidence she carried the recessive allele.