Human Blood Types Have Deep Evolutionary Roots

Rachel Ehrenberg
Oct 23, 2012
http://www.sciencenews.org/view/generic/id/345987/description/Human_blood_types_have_deep_evolutionary_roots

Summary:
According to new research led by Laure Ségural and colleagues (University of Chicago), A, B, and O types of the human blood have evolved at least 20 million years ago in the common ancestor of humans and other primates. The A, B, and O versions of the blood type gene differ slightly, and there exists two ideas about their evolution: first, the A version existed long ago, and the B and/or O types then popped up in several species, and second, all species inherited types A and B from a common ancestor. Ségural's team compared the DNA stretches of humans, chimpanzees, gorillas, bonobos, orangutans, and a few species of monkeys. In their comparison, they found that sections in the A version of human DNA more closely matched the A version of gibbons than the human B version, implying that the A and B groups existed more than 20 million years ago. A suspected reason why evolution favored different blood types is how people with different blood types are more or less susceptible to different pathogens. For example, type O people are more susceptible to cholera and plague, and type A people are more prone to smallpox and blood clots. This diversity could have offered protection over whatever diseases developed.

Connection:
This article connects to our unit on evolution as well as our unit on molecular genetics. It connects to evolution because the article discusses the evolution of blood types in humans; types A, B, and O evolved around 20 million years ago. It also connects to adaptation because different types may have had their benefits, which caused adaptation to maintain diversity. This article connects to molecular genetics because it uses the sequencing of DNA to find the similar blood type DNA sequences between humans, chimpanzees, monkeys, etc.