The deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD) is inherited as a recessive gene on the X chromosome in humans. A phenotypically normal woman (whose father had G6PD) is married to a normal man. What fraction of their sons would be expected to have G6PD?
XY crossed with XXn where n is the trait. It will yield XX, XXn, XY, XnY. Thus, with this crossing, it will produce a normal male and an affected male.
