A Study of the Genetics of Sickle Cell Anemia

Sickle cell anemia is a genetic disease caused by a "defective" allele (or form) of a certain gene. Each person has two alleles that determine if that person has sickle cell anemia or not. If one of the two alleles is the "defective" allele, then that person has sickle cell trait. Sickle cell trait does not result in fatal health problems. Having two "defective" alleles results in sickle cell anemia, a disease that was, until recently, almost always fatal.

The allele causing sickle cell anemia is found most often in people of African ancestry, but it also occurs in others, including persons of Mediterranean, Arabian, and East Indian descent. Several different alleles cause a group of sickle cell disease variants. To simplify matters in this article, we assume there is only one type of sickle cell allele.

Students will study the effect of the allele that causes sickle cell anemia on the survival of a population by using first a physical model and then a mathematical model. The goal is to understand how the genetic process is making the best of a bad situation.