One of the most important services we can render with virtually no cost to ourselves is the donation of blood. In doing so, we learn we're type A, B, AB, or 0. However, many people have no idea what this means. Red blood cell surfaces contain molecules of various sugars. Which sugars are determined by genes. A person can have two genes for the particular configuration that we associate with type A, two genes for type B, one gene for A and one gene for B, or have neither A nor B genes. The results are the four blood types: A, B, AB, and O.
Interestingly enough, these genes are ancient, at least from our
viewpoint. If humans and chimpanzees trace their lineages back, they end up with the
same species as an ancestor. This common ancestor seems to have lived about 6 million
years ago, give or take a bit. Our blood type genes go back at least that far. How do
we know? Because both the chimps and ourselves share these genes, inherited from that
distant ancestor.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.