The inheritance of sickle cell anemia involves incomplete dominance. (S determines normal hemoglobin, it is dominant; s is the sickle cell gene). A homozygous recessive person has sickle cell anemia. A heterozygous person has the sickle cell trait. If parental genotypes are SS and ss, what is the probability of offspring having the sickle cell trait?
A) 50%; half are Ss
B) 25%; one quarter are Ss
C) 100%; all are Ss

Question

Quizplus · Accepted Answer

In this cross, one parent is SS (normal) and the other is ss (sickle cell anemia). All offspring will inherit one S allele from the SS parent and one s allele from the ss parent, making them all heterozygous (Ss) and thus having the sickle cell trait.

The Inheritance of Sickle Cell Anemia Involves Incomplete Dominance