I have recently been reminded that the global distribution of domesticated animals during the time of the Spanish Conquistadors was responsible for the presence of smallpox among their invasion of the America's. It made me look up the global distribution of blood groups, and the following information:
Modern Human Variation: Distribution of Blood Types
Modern Human Variation: Distribution of Blood Types
The majority of the people in the world have the Rh+ blood type. However, it is more common in some regions. Native Americans and Australian Aborigines were very likely 100% Rh+ before they began interbreeding with people from other parts of the world. This does not imply that Native Americans and Australian Aborigines are historically closely related to each other. Most African populations are around 75% Rh+. Europeans have the lowest frequency of this blood type for any continent. They are 60% Rh+. The lowest known frequency is found among the Basques of the Pyrenees Mountains between France and Spain. They are only 47% Rh+.
