Neanderthals and modern humans shared an ancient ancestor who lived about 660,000 years ago, according to scientists who have pieced together the first complete sequence of maternal DNA from humanity’s closest cousins.
The DNA evidence also verified that the two species did not interbreed during the 10,000 to 20,000 years when they coexisted in Europe and western Asia after humans migrated there from Africa.
The last of the Neanderthals died out about 30,000 years ago.
“Neanderthals made no lasting contribution to the modern human (maternal) DNA gene pool,” a team of German, American, Croatian and Finnish researchers wrote in Friday’s edition of the journal Cell.
The team focused on mitochondrial DNA, a relatively short string of 16,565 A’s, T’s, C’s and G’s that spell out 13 genes for controlling the energy sources of cells. Unlike nuclear DNA, which is unique for every person, mitochondrial DNA is passed virtually unchanged from mother to child.
Members of the research group are engaged in a two-year effort to decode the roughly 3 billion letters of nuclear DNA contained in a 38,000-year-old Neanderthal bone fragment discovered in a Croatian cave.
In the process, they collected enough maternal DNA to sequence that genome with a high degree of certainty, said Ed Green, a scientist at the Max Planck Institute for Evolutionary Anthropology in Leipzig.
Comparisons of the Neanderthal sequence to 10 human sequences implies that the two species diverged between 520,000 and 800,000 years ago — much earlier than the 400,000 years scientists previously had estimated.
Scientists have sequenced maternal DNA from thousands of people around the world to study the history of human migration out of Africa. All of them are distinct from the Neanderthal version, Green said.
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