You have learned that people with sickle anemia have hemoglobin that is of a different shape than normal hemoglobin. You also know that people who have this trait inherited it from their parents. Knowing who in a family has sickle cell anemia can help a doctor to predict if other people in the family will inherit the trait. Doctors use models called pedigrees to show which people in the same family have a certain trait. A simple pedigree for sickle cell anemia is shown below. The information in the key can help you to read the pedigree.
A. An individual will have sickle cell anemia if they are female.
B. An individual will have sickle cell anemia only if they have two recessive alleles.
C. An individual will have sickle cell anemia if they have at least one dominant allele.
D. An individual will have sickle cell anemia if they have a sibling with sickle cell anemia.