Chimps and humans split 4 million years ago
February 23, 2007
Chimp in Uganda, photo by R. Butler
New research using DNA analysis suggests that chimpanzees and humans split from a common ancestor just 4 million years ago — much earlier than the 5-7 million years currently accepted by biologists. The study is published in Public Library of Science journal PLoS Genetics.
The researchers — Asger Hobolth (North Carolina State University), Ole F. Christensen (University of Aarhus), Thomas Mailund (University of Aarhus / University of Oxford), Mikkel H. Schierup (University of Aarhus) — compared the DNA of humans with three other species of great apes — chimpanzees, humans, gorillas, and orangutans — to develop a “molecular clock” estimate of when humans diverged.
“Primate evolution is a central topic in biology and much information can be obtained from DNA sequence data,” the authors wrote. “Assuming orangutan divergence [18 million years] ago, speciation time of human and chimpanzee is consistently around 4 [million years ago].”
Sharing about 96 percent of their DNA, chimps are humans’ closest living relatives. Gorillas and orangutans are less closely related.
The study comes the same day that a paper in the journal Current Biology reported the use of tools by chimpanzees in West Africa for hunting smaller primates.