four blood types: a, b, o and AB.

1. A

Type A blood appeared between 25, and 15, BC. At that time, our ancestors who lived on fruits gradually became omnivorous. With the passage of time, farming has become the main mode of production for people living in Europe today, and wild birds and beasts have begun to be domesticated, and people's diet structure has changed accordingly. Even now, most people with type A blood live in Western Europe and Japan.

2. B

Type B blood appeared between about 15, BC and the New Era. At that time, some people in East Africa were forced to migrate from tropical savanna to the cold and barren Himalayas. Climate change has become the main factor for the birth of type B blood. This blood type first appeared in Mongolians, and with their continuous migration to the European continent, many Eastern Europeans are of this blood type today.

3, O

O blood has the longest history. It appeared between 6, and 4, BC, when Neanderthals ate simple meals: weeds, insects and wild animals falling from trees ate the remaining fruits. And 4, years ago, the Krumanon people appeared, and they hunted for a living. After hunting all the wild animals, they moved from Africa to Europe and Asia.

4. AB

The last of the four blood types in the human body is AB, which appeared less than 1 years ago, and is the product of a mixture of Indo-European people who "carry" blood type A and Mongolians who "carry" blood type B.. People with AB blood type have inherited the ability of disease tolerance, and their immune system is more resistant to bacteria, but they are prone to malignant tumors.

Extended information:

rare blood group is a rare or rare blood type. This blood group exists not only in ABO blood group system, but also in rare blood group system.

With the in-depth study of blood group serology, scientists have established rare blood group systems for rare blood group, such as RH, MNSSU, P, KELL, KIDD, LUTHERAN, DEIGO, LEWIS, DUFFY and a series of other rare blood group systems.

There is also a rare blood group system called Mumbai type. There are no A, B and H antigens on red blood cells of this blood type, but there are three kinds of antibodies A, B and anti-H in serum.

basically, type o is the most common blood type in the world. But in some places, such as Norway, there are more people with type A blood. Type A antigens are generally more common than type B antigens. Type AB blood group is also the least ABO blood group because it has both A and B antigens. ABO blood group distribution is related to region and race.

Baidu Encyclopedia-Blood Group System