Why do we have different blood types?

The type of blood in your veins is likely different from the type in your friends and family. Knowing your blood type is important for medical purposes and raises a question about why humans have different blood types.

The four main blood groups are A, B,AB andO. Red blood cells in type A, B, and O blood have different A and B genes.

The University of Minnesota's blood bank's medical director said that the data is suggestive that the reason we have different blood groups is because of Malaria.

According to the Centers for Disease Control and Prevention, Malaria killed 627,000 people in 2020. The red blood cells that cause Malaria accumulate in small blood vessels, blocking the flow of blood and oxygen to the brain. People with group O blood are protected against Malaria. A study in the journal Proceedings of the National Academy of Sciences found that people with type O blood were less likely to develop severe malaria than people with other blood types.

What is the most rare blood type?

A study published in the journal Nature Reviews Microbiology shows that the malaria parasites make red blood cells express a molecule on their surface that acts like a glue that makes un-infecting red blood cells pile up around aninfecting red blood cell. According to a study in the journal Nature Medicine, RIFIN binding weakly to type O red blood cells is a different story than it is to type A red blood cells.

The blood group is only one aspect of a person's blood that affects their risk of Malaria. There are more than one type of antigens that can be found on the surface of red blood cells. The group is called the Duffy group. The two major malaria parasites are resistant to people who lack the Duffy antigen. Malaria is the most common disease in sub-Saharan Africa, but it is rarely seen elsewhere in the world, according to the Malaria Atlas Project.

There is a lot of evidence for why populations that evolved in malaria-prone areas have type O blood, but it is not clear why type A, B andAB blood can be found in relatively high proportions elsewhere. Some scientists point to diseases between different blood types. A study published in the journal Bio Med Research International found that people with type O blood are more likely to have diseases. People with typeAB blood are more likely to have diseases like E. coli and smallpox.

The associations are not convincing, especially not as a reason for why humans have different blood types. The studies did not show a correlation between blood type and the prevalence of diseases. She said that they don't find evidence of blood types causing protection or susceptibility to diseases.

About 15% of Caucasians, 8% of Black people, and 1% of Asians have the Rhesus factor on the surface of their blood cells, which makes them Rh positive, but it is unclear why. This is what the blood groups indicate, for example A+ or B-. A 2012 study published in the journal Human Genetics looked at whether there was an advantage to being Rh negative that would keep this genetic variation around, despite it sometimes causing rhesus disease. They concluded that either the benefit existed in the evolutionary past or that humans have those two Rh types because of random chance.

The original was posted on Live Science on September 29, 2011.