Science Homework: Alleles?

Question

Does a male with Duchenne muscular dystrophy [a sex-linked disorder] inherit the allele for the disorder from his mother or father?

Answer 1

An affected male would get the allele for the disease from the mother. It is a sex-linked disorder on the X Chromosome. The father would have to be affected for the son to inherit it. This is not the case, though, since the boy inherits it from the mother who is a carrier and unaffected.

Answer 2

This allele is on the X-chromosome. A male gets an X from Mom and Y-chromosome from Dad. So he would inherit this chromosome with the Duchenne muscular dystrophy from his mother.