Chimps 'more evolved' than humans
Chimpanzees' genes have changed more under Darwinian selection
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Tuesday, 17, Apr 2007 04:34
Chimpanzees have evolved genetically more than humans, scientists claim today in a new study.
Researchers from the University of Michigan believe that since the split from humans' and chimpanzees' common ancestor, more genes from chimpanzees have changed under positive Darwinian selection than from humans.
They argue that the findings contradict the common belief that humans, with relatively large brains and capabilities, were specially favoured by natural selection.
The team reached their conclusion after studying 14,000 human and chimpanzee genes.
Writing in the journal Proceedings of the National Academy of Sciences, they argue that an effective human population size smaller than previously thought reduced the effectiveness of natural selection.
This, they claim, makes chance events such as the survival of certain gene variants more important in humans than in chimpanzees. As such, chance events play a greater role than positive Darwinian selection.
Their results also showed that positive selection acted on different genes in the two species and the selected genes were involved in different biological processes.
Much more remains to be researched about what traits were beneficial in human and chimpanzee evolution, as they conclude that "little is currently known about which traits have been under positive selection".