DNA studies: Human And Chimp Interbreeding

[Guest guest]

Human And Chimp Interbreeding Continued Long After Species Diverged

http://www.medicalnewstoday.com/healthnews.php?newsid=43616

DNA studies indicate that Humans and chimpanzees carried on

interbreeding for thousands, perhaps millions of years after the two

species diverged.

The researchers say human evolution seems to have been much more

complex than previously thought. This exchanging of genes probably

helped both species survive more successfully in their environments.

Team member, Prof. D Reich says that this is just a hypothesis as it

has not yet been proved. However, he said it would explain multiple

features of their data. Their hypothesis is that there was an

exchange of genes between our human ancestors and chimpanzees after

the two species diverged.

This study was carried out at the Harvard Medical School and the

Broad Institute of MIT and Harvard. You can read about the study in

the journal Nature.

Chimpanzee DNA sequences are the most similar to humans in the animal

kingdom. After divergence, the differences took place as a result of

tiny mutations over time. If scientists can pinpoint these

differences in human's and chimp's genomes, it is possible to map out

a history of each species' evolution.

The researchers say divergence happened between 6.3 - 5.4 million

years ago. This clashes with some fossil findings and calculations.

The Toumai fossil of Chad places man before Chimps and Humans

diverged, 6.4 - 7.4 million years ago.

If the Toumai fossil calculations are right, then the human-chimp

speciation may have taken place over a long period with episodes of

genetic exchanges between the two emerging species. It is possible,

say the researchers, that the Toumai datings are wrong.

How the two emerging species, one walking upright while the other

moved around on all-fours, managed to view each other as attractive

mates - is something we will probably never know.