Dogs

Hemoglobin and Fitness Lab

Modified from a lab written by Dr. Janet Lanza, University of Arkansas at Little Rock, Biology Department

Question: What is natural selection? This is the essential question students will “discover” the answer to after this lab activity.

Background Information

Sickle Cell Anemia and Malaria

Sickle cell anemia is a hereditary disorder that mostly affects people of African ancestry, but also occurs in other ethnic groups, including people who are of Mediterranean and Middle Eastern descent. More than 70,000 Americans have sickle cell anemia and about 2 million Americans—and one in every 12 African Americans—have sickle cell trait (this means they carry one gene for the disease, but do not have the disease itself).

Sickle cells anemia occurs when a person inherits two abnormal genes (one from each parent) that cause their red blood cells to change shape. Instead of being flexible and round, these cells are more rigid and curved in the shape of the farm tool known as a sickle—that’s where the disease gets its name. The shape is similar to a crescent moon.

What is Sickle Cell Anemia?

Sickle cell anemia is a blood disorder that affects hemoglobin, a protein found in red blood cells that helps carry oxygen throughout the body.

Red blood cells with normal hemoglobin (HbA) move easily through the bloodstream, delivering oxygen to all of the cells of the body. Normal red blood cells are shaped like doughnuts with the centers partially scooped out and are soft and flexible.

Sickle cell anemia occurs when an abnormal form of hemoglobin (HbS) is produced. HbS molecules tend to clump together, making red blood cells sticky, stiff, and more fragile and causing them to form into a curved, sickle shape. Red blood cells containing HbS can go back and forth between being shaped normally and being shaped until they eventually become sickle shaped permanently. Instead of moving through the bloodstream easily,...