Human is a creature that has a lot of mystery. Have you ever wondered why the blood group of each person is different?
The presence of human blood for the infectious disease ward. However, some blood group incompatibility is really just an accident of human evolution itself.
There are four main four types of blood groups. Blood type A is the most ancient blood. Because blood has been there since before the human species evolved from a common ancestor hominidnya.
Blood type B allegedly came from 3.5 million years ago from a genetic mutation that modifies one of the sugars that are on the surface of red blood cells. Starting at 2.5 million years ago, a mutation occurred and make it a slow sugar genes.
Alhasi, blood type O is created that has no sugar version of the blood group A or B. Then, there is blood type AB have sugar blood group A and B. Sugar is what makes some kind of blood type did not match.
If the blood of the donor blood type A is given to individuals with blood type B, recipient's immune system will recognize it as an invader of foreign sugar and a hint of attack.
Immune reactions that occur can be very deadly. Blood type O negative is known as the "universal donor" because it does not have a molecule that would provoke such reactions, 'negative' in this case the lack of other surface molecules known as Rh antigen.
However, the discrepancies are not part of the reason people have blood type, according to Harvey Klein transfusion medicine chief at the National Institutes of Health Clinical Center.
"Blood transfusion is a recent phenomenon (hundreds of years, not millions of years ago), and therefore it has nothing to do with the evolution of blood group," he explained.
Causes of evolution or at least one of whom is a disease. For example, according to Christine Cserti hematologist-Gazdewich of the Toronto General Hospital, malaria seems to be the main force behind the selectivity of blood type O.
Blood type O are more common in Africa and other parts of the world that has a high burden of malaria.This implies, brings a kind of blood type evolutionary advantage.
"In this case, the advantage is, cells infected with malaria do not stick well to the blood cell blood group O or B," said Cserti-Gazdewich. Malaria-infected blood cells tend to stick to the cell with blood sugar A.
Afterwards, the blobs are known as 'rose' will be formed and this can be very deadly clots when formed in vital organs, like the brain.
As a result, according to a 2007 study published in the Proceedings of the National Academy of Sciences, the blood type O will not feel the pain is too severe when infected with malaria.
On the other hand, the blood type O are more susceptible to other diseases. For example, the blood type O are more susceptible to Helicobacter pylori, the bacterium that causes ulcers, says Klein.
Unfortunately, research has not shown whether this or some other disease to explain why humans still have blood.
