A single mutant allele gives rise to an abnormal form of hemoglobin (HbS) instead of HbA.Homozygotes (HbS HbS) develop sickle-cell anemia.

1. A single mutant allele gives rise to an abnormal form of hemoglobin (HbS)

instead of HbA. Homozygotes (HbS HbS) develop sickle-cell anemia.

Heterozygotes (HbA HbS) show few obvious symptoms unless under duress.

(3 Points) 

Suppose a woman's mother is homozygous for the HbA allele,

and they plan to have children. The father has been found to be a

heterozygote, showing a few symptoms. 

For each of her pregnancies, state the probability that this couple will have a

child who is...

(A) Homozygous for the HbS allele:_________________

(B) Homozygous for the HbA allele:________________