Using a patient's own stem cells, researchers have corrected the genetic alteration that causes sickle cell disease, a painful, disabling inherited blood disorder that affects mostly African-Americans. The corrected stem cells were coaxed into immature red blood cells in a test tube that then turned on a normal version of the gene
Animated video walks students through a sickle cell anemia case study, guided by a genetic counselor, with breaks for questions and interactive responses.
This hands-on activity, used in conjunction with the film The Making of the Fittest: Natural Selection in Humans, teaches students about population genetics, the Hardy-Weinberg principle, and how natural selection alters the frequency distribution of heritable traits. It uses simple simulations to illustrate these complex concepts and includes exercises such as calculating allele and genotype frequencies, graphing and interpretation of data, and designing experiments to reinforce key concepts in population genetics.
A keenly observant young man named Tony Allison, working in East Africa in the 1950s, first noticed the connection and assembled the pieces of the puzzle. His story stands as the first and one of the best understood examples of natural selection, where the selective agent, adaptive mutation, and molecule involved are known-and this is in humans to boot. The protection against malaria by the sickle-cell mutation shows how evolution does not necessarily result in the best solution imaginable but proceeds by whatever means are available.
