Paper: Genetic evidence for complex speciation of humans and chimpanzees

Nature advance online publication 17 May 2006 | doi:10.1038/nature04789;
Received 5 November 2005; Accepted 7 April 2006; Published online 17 May
2006
Genetic evidence for complex speciation of humans and chimpanzees

Nick Patterson, Daniel J. Richter, Sante Gnerre, Eric S. Lander and David
Reich

Abstract
The genetic divergence time between two species varies substantially across
the genome, conveying important information about the timing and process of
speciation. Here we develop a framework for studying this variation and
apply it to about 20 million base pairs of aligned sequence from humans,
chimpanzees, gorillas and more distantly related primates. Human-chimpanzee
genetic divergence varies from less than 84% to more than 147% of the
average, a range of more than 4 million years. Our analysis also shows that
human-chimpanzee speciation occurred less than 6.3 million years ago and
probably more recently, conflicting with some interpretations of ancient
fossils. Most strikingly, chromosome X shows an extremely young genetic
divergence time, close to the genome minimum along nearly its entire length.
These unexpected features would be explained if the human and chimpanzee
lineages initially diverged, then later exchanged genes before separating
permanently.

Abstract and Full Text Links at Nature
http://www.nature.com/nature/journal/vaop/ncurrent/abs/nature04789.html

Posted by
Robert Karl Stonjek


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