Sickle-cell anemia is caused by a recessive mutation in the hemoglobin gene. However, heterozygote individuals also show a small percentage of sickled red blood cells. What type of inheritance pattern is this an example of?
A) Polygenic inheritance
B) Sex linked
C) Chromosomal nondisjunction
D) Incomplete dominance

Question

Quizplus · Accepted Answer

This is an example of incomplete dominance because heterozygous individuals (carriers of the sickle-cell trait) exhibit a phenotype that is not as severe as those with two copies of the mutated gene, but still show some symptoms (a small percentage of sickled cells), indicating that neither allele is completely dominant over the other.

Sickle-Cell Anemia Is Caused by a Recessive Mutation in the Hemoglobin