Blood Type Distribution In the USA and Around the World

This is the Chart for Blood Types in the USA

Below are maps of blood types around the world, courtesy of "Modern Human Variation"

All human populations share the same 27 known blood systems, although they differ in the frequencies of specific types. Given the evolutionary closeness of apes and monkeys to our species, it is not surprising that some of them share a number of blood typing systems with us as well.

This can be seen with the global frequency patterns of the type B blood allele (shown in the map below). Note that it is highest in Central Asia and lowest in the Americas and Australia. However, there are relatively high frequency pockets in Africa as well. Overall in the world, B is the rarest ABO blood allele. Only 16% of humanity have it.

The A blood allele is somewhat more common around the world than than B. About 21% of all people share the A allele. The highest frequencies of A are found in small, unrelated populations, especially the Blackfoot Indians of Montana (30-35%), the Australian Aborigines (many groups are 40-53%), and the Lapps, or Saami people, of Northern Scandinavia (50-90%). The A allele apparently was absent among Central and South American Indians.

The O blood type (usually resulting from the absence of both A and B alleles) is very common around the world. About 63% of humans share it. Type O is particularly high in frequency among the indigenous populations of Central and South America, where it approaches 100%. It also is relatively high among Australian Aborigines and in Western Europe (especially in populations with Celtic ancestors). The lowest frequency of O is found in Eastern Europe and Central Asia, where B is common.