Question

The pedigree on the right shows the inheritance pattern for an X-linked recessive disorder.

Answer 1

The right answers are : XAXA and XAXa.

A genetic disease is referred to as X-linked recessive inheritance when:

* the gene involved in the mutation is on the sex chromosome X

* the mutation is recessive, a man carrying the mutant allele will be ill, because hemizygote for the X chromosome. The presence of both mutant alleles is necessary for the disease to be expressed in a girl.

According to the image, the mother has always transmitted a healthy allele (XA) so the answers are the genotypes carrying this allele.

Answer 2

I think it's XAXA and XAXa because x-linked rec. usually is only fully present in males