Question

If the mode of inheritance is X-linked recessive what is the best reason that you don’t see the disorder in females?
a. They have two XX chromosomes c. b. They don’t have a Y chromosome that d.
the X is linked to
Females don’t have X chromosomes Females don’t inherit tratis from the X chromosome

Answer 1

The answer is a). If the inheritance is X-linked recessive, then it should show up in females in homozigousity, while in males it will manifestate in any case. Generally speaking, if you name "a" the recessive form and "A" the dominant one, then the disorder appears in "aa" individuals, while in the "Aa" case you won't have any manifestation of the recessive phenotype. The case of sexual chromosomes is a peculiar one, since every male will have only one chromosome x, and thus any allele of the gene will manifestate. Females have a pair of x chromosomes and they will follow the standard rule about inheritance. That's the reason why recessive disorders will manifestate in homozigousity only.