When modern humans met Neanderthals

doi:10.1126/science.372.6538.115

GSTDTAP > 气候变化

DOI	10.1126/science.372.6538.115
	When modern humans met Neanderthals
	Ann Gibbons
	2021-04-09
发表期刊	Science
出版年	2021
英文摘要	The four-story labyrinth of galleries in Bulgaria's Bacho Kiro cave has long been a magnet for all sorts of humans. Neanderthals came first, more than 50,000 years ago, and left their characteristic Mousterian stone tools among the stalagmites. Next came modern humans in at least two waves; the first littered the cave floor with beads and stone blades stained with ochre, about 45,000 years ago. Another group settled in about 36,000 years ago with even more sophisticated artifacts. Now, a new ancient DNA study shows the first group of modern humans at Bacho Kiro carried a recent legacy from Neanderthals: Those people's ancestors had interbred with our extinct cousins as recently as six generations, or 160 to 180 years, previously. However, another study out this week, of what may be the oldest modern human in Europe, shows the first wave of moderns had diverse Neanderthal legacies. The genome of a dark-skinned, brown-haired, brown-eyed woman from Zlatý kůň cave in the Czech Republic included only 3% Neanderthal DNA, which likely came from a long-ago tryst in the Middle East, not from recent contact, the study suggests. Taken together, these genomic snapshots offer a glimpse into the identities of the mysterious modern humans who first set foot in Europe and their relationship to Neanderthals, who vanished about 40,000 years ago. “You're talking about multiple waves of modern humans,” says paleoanthropologist Chris Stringer of the Natural History Museum in London. “Some groups mixed with Neanderthals, and some didn't. Some are related to later humans and some are not.” ![Figure][1] CREDITS: (MAP) K. FRANKLIN/ SCIENCE ; (DATA) PRÜFER ET AL., NATURE ECOLOGY & EVOLUTION , DOI: 10.1038/S41559-021-01443-X (2021); HAJDINJAK ET AL., NATURE , DOI: 10.1038/S41586-021-03335-3 (2021) The new revelations fill out the story of these ancient encounters, says Mateja Hajdinjak, a postdoc at the Max Planck Institute for Evolutionary Anthropology (MPI) and an author of the Bacho Kiro study. “For the first time, we're getting ancient DNA from multiple early modern humans that tells us so much about their interactions with some of the very last Neanderthals in Europe,” she says. After modern humans trekked out of Africa 60,000 to 80,000 years ago, they interbred at least once with Neanderthals, most likely in the Middle East about 50,000 years ago, previous ancient DNA research has shown. Those studies include analyses of two early modern humans from Eurasia: a 45,000-year-old thigh bone of a man from Ust'-Ishim in Siberia, and the jawbone of a young man from Petştera cu Oase cave in Romania, dated to between 37,000 and 42,000 years ago. The Oase man inherited as much as 6.4% of his DNA from a recent Neanderthal ancestor. But he lived at least 5000 years after modern humans had arrived in Europe. This week's studies offer a genetic glimpse of an earlier time, when modern humans first ventured into Neanderthal territory. Hajdinjak and MPI paleogeneticist Svante Pääbo analyzed genomes from Bacho Kiro, where last year researchers used a new protein-based method to show that bone fragments in a middle layer of cave sediments came from modern humans ( Science , 15 May 2020, p. [697][2]). In the new study, the researchers sequenced genomes from a molar and bone fragments from that middle layer and directly dated them to 42,580 to 45,930 years ago. They also sequenced DNA from bone found in a younger layer and dated it to 35,000 years ago. Remains from both layers were modern humans, but from different populations, they report in Nature this week. The genomes show the three oldest modern humans at Bacho Kiro were distantly related to a 40,000-year-old partial skeleton from Tianyuan in China, as well as to other ancient and living East Asians and Native Americans. That suggests they all descended from an early population that once spread across Eurasia, but whose descendants in Europe seem to have died out. The lineage survived in Asia, later giving rise to people who migrated to America. Those modern humans had also inherited 3% to 3.8% of their DNA from Neanderthal ancestors. The chunks of Neanderthal DNA were long, which suggested they arose from mixing only six generations earlier, because with each new generation, recombination breaks stretches of DNA in shorter fragments. That mating must have been different from the one that gave the younger Oase man his larger Neanderthal legacy. This “suggests that such mixing was common,” Hajdinjak says. Genomic analysis of the female skull found in Zlatý kůň cave (which means golden horse in Czech), near Prague, tells a different story, according to a paper this week in Nature Ecology & Evolution by a team led by paleogeneticists Johannes Krause and Kay Prüfer of MPI. The woman's Neanderthal DNA likely came from the first known interbreeding, between Neanderthals and the ancestors of all living Eurasians, as modern humans expanded out of Africa and moved into Eurasia, Krause says. Researchers hadn't been able to directly date the Czech skull, which was discovered in the 1950s, because bovine glue used to repair it contaminated the bones. So Krause and Prüfer turned to a clever dating method that uses the ancestral mating with Neanderthals as a time marker. The chunks of Neanderthal DNA in the genome from the Zlatý kůň skull suggest the woman was born 60 to 80 generations (roughly 2000 years) after her ancestors mated with Neanderthals, they conclude. The 45,000-year-old Siberian male inherited his shorter Neanderthal DNA chunks about 85 to 100 generations after that same encounter. That suggests the Czech female lived before the Siberian male and could be as old as 47,000 years—the oldest known modern in Europe, Krause says. The authors make a “compelling” case that the woman lived at least 45,000 years ago, says population geneticist John Novembre of the University of Chicago. Krause's team also found that unlike the Bacho Kiro individuals, the Zlatý kůň skull was no more closely related to ancient Asians than to Europeans. This suggests she came from an ancient population that had not yet differentiated genetically into Asians and Europeans, Krause says. The differences in how often modern humans mated with Neanderthals could reflect the small population sizes of each group at the time, Novembre suggests. And Zlatý kůň is located in what was perhaps the northern edge of Neanderthal territory, whereas Bulgaria's Balkan Mountains were a known refuge for Neanderthals as modern humans pushed into Europe. The new data show that all of the modern human lineages vanished by the advent of the last ice age, which reached its peak about 20,000 years ago. After the ice melted, other modern humans from Eurasia repopulated the continent. “Multiple groups headed out [to Eurasia], but it seems like only a fraction of these early modern humans left progeny,” Novembre says. [1]: pending:yes [2]: http://www.sciencemag.org/content/368/6492/697
领域	气候变化 ; 资源环境
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/322042
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	Ann Gibbons. When modern humans met Neanderthals[J]. Science,2021.
APA	Ann Gibbons.(2021).When modern humans met Neanderthals.Science.
MLA	Ann Gibbons."When modern humans met Neanderthals".Science (2021).