The pedigree on the right shows the inheritance pattern for an x-linked recessive disorder. the mother of the individuals circled in pink is not shown on the pedigree. based on the phenotypes of these individuals and their father, what are the possible genotypes of their mother? check all of the boxes that apply. xaxa xaxa xaxa

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.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."