Question

Two parents who do not have sickle cell anemia have a child that has the disease. The parents are both:_______

A) Pleiotropic for the sickle cell allele
B) Homozygous for the sickle cell allele
C) Homozygous for the normal allele
D) Heterozygous for the sickle cell allele
E) Epistatic for the sickle cell allele

Answer 1

Answer:D

Step-by-step explanation:

Both parent are Heterozygous for the sickle cell allele.

Both parent have sickle cell trait in which the both posses one abnormal allele of the hemoglobin beta gene (AS heterozygous genotype)

When two AS parents mate, probability of giving birth to a sickle cell anemia child is 1/4

AS + AS= AA, AS, AS, SS