Human and chimpanzee ancestors may have split into different species millions of years earlier than scientists thought, a new study of chimpanzee mutation rates suggests.
In each generation, chimps’ average mutation rate is one DNA chemical unit changed out of every 83 million, researchers report in the June 13 Science. That mutation rate is nearly identical to the rate previously calculated for humans using similar methods (SN Online: 6/13/11). If the human and chimp mutation rates remained constant throughout evolutionary history, the species would have shared their most recent common ancestor about 13 million years ago.