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An international team of researchers has found
evidence that suggests that the ABO blood types
found in all primates developed in a shared common
ancestor. In their paper published in the
Proceedings of the National Academy of Sciences, the
team describes how a genetic analysis of the ABO
blood types revealed that they developed much
earlier than had been previously thought, which they
say, shows that ABO blood types did not develop
independently in different species.
There are four major blood types in humans and all
other primates: A, B, AB and O. Each is identified
by the antigens on the surface of the individual red
blood cells and the corresponding antibodies that
respond to them. They are known collectively as ABO
blood types and scientists don't know why they
evolved or what the reason is for having more than
one.
Since the discovery of blood types at the beginning
of the last century, scientists have believed that
they evolved separately in humans and other primates.
This new study contradicts that belief by suggesting
that ABO blood types developed before primates split
off into different species, suggesting that the ABO
blood types in modern primates all evolved from a
common ancestor.
To come to this conclusion, the researchers built on
previous evidence that had found that two amino
acids responsible for the development of A and B
blood types were identical for macaques, humans,
baboons, gibbons and orangutans. They performed a
genetic analysis of blood types from three species
of primates: Hylobates lar, Macaca mulatta and
Colobus angolensis and found that the blood types
for all three developed much earlier than
researchers had previously thought – approximately
20 million years ago, a point in history prior to
the time when each had split off from a common
ancestor, evolving into a unique species.
This suggests that ABO blood types evolved in a
common ancestor and has persisted in each species
since that time.
In comparing and highlighting the differences
between primates with different blood types, using
the genetic evidence, the researchers also found
that for one small region of the genome, people with
type A blood are more similar to a Gibbon with type
A blood than they are to people with type B blood.
For more information
PNAS October 22, 2012 doi: 10.1073/pnas.1210603109
(MDN)
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