Evidence of evolution is in the genetic blood disorders which fight malaria. These disorders are aspects of evolution which are both terrible disorders and protective mechanisms. Malaria is historically one of the biggest killer of humans in the history of our time on the planet. The original strains operated with a virulence that simply killed or debilitated humans so they could not do the hunting and gathering needed in order to survive.
In Malaria, the anopheles mosquito carries parasites known as sporozoites. The mosquito introduces the sporozoites when it bites a human or animal. The sporozoites enter the liver, where they mature and change into merozoites. The merozoites enter the bloodstream and infect the blood. The destruction of the red blood cells results in anemia, and other problems with the blood chemistry occur when the free hemoglobin is released into the blood chemistry. Liver and kidney failure are dire consequences of this parasitic disease.
Of the 300 to 500 million cases of malaria each year, the Centers for Disease Control (CDC) estimate that one million people die. There are four different types of malaria, the most destructive being Falciparum malaria, which can kill within hours.
In our evolutionary tweaking, one genetic disorder, Sickle Cell Anemia has malaria fighting properties. People with one gene for sickled hemoglobin and one gene for normal hemoglobin (Sickle Cell Trait) are found to be more resistent to malarial parasitic infection. No one knows the exact mechanism by which the trait protects against malaria, the the trait is a definitive source of resistance which is easly passed on to the next generation, as people with the trait will live long enough to reproduce.
Another genetic disorder, Glucose 6-phosphase Dehydrogenesis, or G6PD, is said to have anti malarial properties. In this bit of evolutionary tweaking, a blood enzyme, Glucose 6-phosphase is deficient. This enzyme serves as a catalyst which converts another chemical, NADPH to NADPHA when substances known as “oxidants” get into the bloodstream. Oxidants are in foods, naptha, and sulfanimide antibiotics. The oxidants are very destructive of red blood cells and the protection keeps them whole. In the G6PD individual, a type of anemia called hemolytic anemia is caused. The Italians call G6PD “Favism” because fava beans are powerful troublemakers.
G6PD is a known factor in fighting malaria. While the exact mechanisms are not known, there is obvious evidence that malarial reactions are less severe in G6PD.
The most amazing part of evolution is that the disorders that come from evolutionary tweaking, evolve themselves. There is a myth that only Africans or African Americans have Sickle Cell or the Trait. The truth is that there are hundreds of variants of sickle cell throughout the Mediterranean, Asia, and the middle East. There are hundred of variants of G6PD along the same parts of the world.
Google Health: Malaria
Harvard Edu Sickle Cell and Malaria
G6PD and Malaria
