Question

which allele combination represents a male who has an x - linked recessive disorder?
○ x^a y
○ x^a y
○ x^a x^a
○ x^a x^a

Explanation:

Males have XY chromosomes. For X - linked recessive disorders, a male with the disorder has the recessive allele on his X (since Y has no corresponding allele). So the allele combination should be \(X^{r}Y\) (assuming \(r\) represents the recessive allele). Among the options, \(X^{r}Y\) (the second option, assuming the second option is \(X^{r}Y\)) fits as males with X - linked recessive have the recessive allele on X and Y.

Answer:

\(X^{r}Y\) (assuming the second option is \(X^{r}Y\), e.g., if the options are A. \(XY\), B. \(X^{r}Y\), C. \(X^{R}X^{r}\), D. \(X^{R}Y\), then the answer is B. \(X^{r}Y\))