Biology 11th Edition by Cecie Starr ,Ralph Taggart

تمرين 27

As Section 3.6 explains, a single mutant allele gives rise to an abnormal form of hemoglobin ( Hb S instead of Hb A ). Homozygotes ( Hb S Hb S ) develop the genetic disease sickle-cell anemia. Heterozygotes ( Hb A Hb S ) show few obvious symptoms.
A couple who are both heterozygous for the Hb A allele plan to have children. For each of the pregnancies, state the probability that this couple will have a child who is:
a. homozygous for the Hb S allele
b. homozygous for the Hb A allele
c. heterozygous Hb A Hb S