Question

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. $x^{a}x^{a}$ $x^{a}x^{a}$ $x^{a}x^{a}$ done

Explanation:

• For X - linked recessive disorders, females have two X chromosomes (\(X^{A}X^{A}\), \(X^{A}X^{a}\), \(X^{a}X^{a}\)) and males have one X and one Y chromosome (\(X^{A}Y\) or \(X^{a}Y\)).
• The father's genotype is \(X^{a}Y\) (assuming he is affected as per the pedigree context).
• The daughters (circled in pink) have a green - shaded part (indicating they have the recessive allele). Since they get one X from father (\(X^{a}\)) and one from mother.
• If the mother is \(X^{a}X^{a}\), all daughters will be \(X^{a}X^{a}\) (affected). If the mother is \(X^{A}X^{a}\), daughters can be \(X^{a}X^{a}\) (if they get \(X^{a}\) from mother) or \(X^{A}X^{a}\) (if they get \(X^{A}\) from mother). The son (also in the pink - circled group) gets Y from father and X from mother.

Answer:

\(X^{a}X^{a}\), \(X^{A}X^{a}\)