Glucose-6-phosphate dehydrogenase deficiency (G6PD)is inherited as a recessive allele of an X-linked gene in humans.A woman whose father suffered from G6PD marries a normal man.
(a)What proportion of their sons is expected to be G6PD?
(b)If the husband was not normal but was G6PD deficient,would you change your answer in part (a)?

Question

Quizplus · Accepted Answer

(a) Since the woman is a carrier (heterozygous) for the G6PD deficiency allele, she can pass either the normal X chromosome or the G6PD deficient X chromosome to her sons with equal probability. Therefore, 1/2 of their sons are expected to be G6PD deficient.
(b) If the husband was also G6PD deficient, then all of their sons would receive the G6PD deficient X chromosome from their mother and would be G6PD deficient. Therefore, the answer would change to (a) no, as all of their sons would be G6PD deficient.

Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD)is Inherited as a Recessive Allele of an X-Linked