Members of a group including the Zlatý kůň woman and the Ranis individuals travel across Europe some 45,000 years ago (illustration). Credit: Tom Björklund
The oldest human genomes ever sequenced are helping to illuminate some extremely ancient baby-making.
The Neanderthal DNA found in all people with ancestors outside Africa entered the family tree much more recently than previously thought, according to two analyses that together examine DNA from people who lived across Eurasia over the past 45,000 years. One study1 finds that modern humans swapped genes with our sister species in a roughly 7,000-year period starting around 50,500 years ago; the other2 finds that the mixing took place between 45,000 and 49,000 years ago.
The data also suggest that some genetic variants from Neanderthals were helpful to modern humans encountering new climates and diseases outside of Africa. The findings are published today by separate teams, in papers in Science1 and Nature2.
That both papers reinforce the idea that the ancestors of all people outside Africa got their Neanderthal ancestry in a single swoop is “striking”, says Alexander Platt, a geneticist at the University of Pennsylvania in Philadelphia, who was not involved with either study. “It’s eye-opening”, he says, that this model of human evolution is correct.
Dating details
Neanderthals and modern humans shared the planet for thousands of years. Whether our two species mingled was hotly debated for decades — until research revealed that Neanderthal DNA makes up a small percentage of the genomes of all humans currently living, other than people whose ancestry comes solely from sub-Saharan Africa.
Since then, the details of the human–Neanderthal meet cute have remained “one of the main questions” in human evolutionary biology, says Benjamin Peter, a population geneticist at the Max Plank Institute for Evolutionary Anthropology in Leipzig, Germany, and a co-author of the Science study.
Neanderthals, who lived in what’s now Europe and western Asia, and modern humans, who evolved in Africa, probably met and mingled throughout our shared time on Earth. Previous research estimated that any gene flow between them did not leave a mark until more recently ― as early as 65,000 years ago.
Koněprusy cave at the Zlatý kůň site in the Czech Republic, where blasting in 1950 led to the discovery of the remains of a woman who lived some 45,000 years ago.Credit: Martin Frouz
The authors of the Nature paper reassessed the timing of that interbreeding by examining the DNA of a male Homo sapiens found near Ranis, Germany, and that of a female Homo sapiens whose remains were discovered in a cave at a site called Zlatý kůň in the Czech Republic. The researchers’ analysis showed that both people lived roughly 45,000 years ago, making them the oldest Homo sapiens genomes ever sequenced.
