Respuesta :
The south and central American Indians are nearly 100% type o for the abo blood system because of founder principle and genetic drift.
Founder principle is a principle in genetics where a part of population is isolated from the original population and forms a new one which has no resemblance to original.
Genetic drift is change in frequency of an existing gene variant in population with random chance.
When migrants with O blood group came into the population with other blood group the original population with other blood group may have become minority and was suppressed by this new population which begin to grow.
Natural selection can also come into act with a situation like this.
Also, it is also concluded in some paper that the main genetic pool of founding population of America can also be same which is the reason for south and central american indians being type O.
To know more about founder principle and genetic drift,
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