Chimps are more promiscuous than humans and thus may have higher mutation rates in their males' DNA.ALAMY. A genetic analysis has called into question the controversial claim that early humans and chimpanzees interbred before splitting into separate species. "Many evolutionary biologists were pretty skeptical" about the interbreeding scenario, says evolutionary geneticist Soojin Yi of the Georgia Institute of Technology in Atlanta. She argues that her explanation — which stems from promiscuity differences among primate species — is "simpler and hence more likely".... Now Yi, together with Daven Presgraves of the University of Rochester, have reanalysed the data and suggest that species differences in the levels of female promiscuity can account for the chromosomal inconsistency. The original hypothesis is "way more of a headache for evolutionary biologists", says Yi. The data "can also be explained very well by well-established ideas in molecular evolution"
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