Morgan BellWe ain’t nothing but mammals
May 18th 2006 14:23
Our human ancestors were having sex with chimpanzees long after splitting from the chimp lineage, according to a recent study into human and chimp genomes.
The study was run by the Broad Institute and Harvard University in Cambridge, Massachusetts. Researcher David Reich told the New Scientist how his team “compared the genomes of humans, chimps and gorillas using a molecular clock’ to estimate how long ago the three groups diverged.” While humans are estimated to have diverged from chimps 6.3 million years ago, research revealed that some parts of the genome may have diverged up to 4 million years prior to that.
The discovery of what is called the Toumai fossil has thrown further confusion on the primitive human-chimp relationship. The Toumai fossil has both human and ape features, causing great disagreement as to whether it is the remains of the oldest known human, or those of an ape.
"It is possible that the Toumai fossil is more recent than previously thought. But if the dating is correct, (it) would precede the human-chimp split," said researcher Nick Patterson told Discovery News.
“The fact that it has human-like features suggest that human-chimp speciation may have occurred over a long period with episodes of hybridization (inter-breeding) between the emerging species."
These findings point towards the hypothesis that human and chimp lineages split some 10 million years ago, but later rehybridised by interbreeding. Natural selection favoured the interbred species as they carried more fertile X chromosomes.
(image from flickr.com)
The study was run by the Broad Institute and Harvard University in Cambridge, Massachusetts. Researcher David Reich told the New Scientist how his team “compared the genomes of humans, chimps and gorillas using a molecular clock’ to estimate how long ago the three groups diverged.” While humans are estimated to have diverged from chimps 6.3 million years ago, research revealed that some parts of the genome may have diverged up to 4 million years prior to that.
"It is possible that the Toumai fossil is more recent than previously thought. But if the dating is correct, (it) would precede the human-chimp split," said researcher Nick Patterson told Discovery News.
“The fact that it has human-like features suggest that human-chimp speciation may have occurred over a long period with episodes of hybridization (inter-breeding) between the emerging species."
These findings point towards the hypothesis that human and chimp lineages split some 10 million years ago, but later rehybridised by interbreeding. Natural selection favoured the interbred species as they carried more fertile X chromosomes.
(image from flickr.com)
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