overview
- Many people carry small pieces of Neanderthal DNA, evidence of interbreeding between Neanderthals and ancient human ancestors.
- Two new studies suggest that interbreeding occurred during the limited period when ancient humans left Africa.
- Clarifying that timeline narrows the range of possible times for humans to spread to new continents.
The genetic code of many people hides mysteries that have long intrigued scientists. It’s a tiny piece of Neanderthal DNA that persists tens of thousands of years after the species disappears.
Most people outside Africa can attribute about 1% to 2% of their DNA to Neanderthal ancestry.
However, the details of its evolutionary history remain unclear. How often did ancient humans and Neanderthals interbreed? When exactly did it happen? Why did Neanderthals become extinct and why did modern humans survive? That Neanderthal DNA What is it bringing us now?
Two research groups independently analyzed collections of ancient genomes and reached the same conclusions about some of their core questions. published research Published in Nature magazine and thursday science Evidence suggests that ancient humans and Neanderthals interbred for a limited period of time as humans left Africa and migrated to new continents.
The results suggest that a wave of interbreeding occurred approximately 43,500 to 50,500 years ago. Then, over the next 100 generations, most, but not all, of the Neanderthal DNA was culled. The remaining DNA is now associated with traits such as skin pigmentation, immune response, and metabolism.
New findings suggest that this interbreeding event occurred more recently than previous estimates suggested, shifting and narrowing the window during which humans may have spread to places like modern-day China and Australia. That’s what it means.
The importance of fossilized human remains dating back more than 50,000 years, discovered in Europe and other parts of the world, has also been revealed. According to a new study, those populations became extinct and reached an evolutionary dead end.
“Human history is not just a success story. In fact, humans went extinct several times,” said Johannes Krause, author of the Nature paper and professor at Germany’s Max Planck Institute for Evolutionary Anthropology. “There are multiple lineages that we’re identifying now that didn’t affect later people.”
The discovery also shows how adept anthropologists are at reconstructing ancient DNA and analyzing it to infer the course of human history.
Priya Muajani, author of the Science paper and assistant professor of molecular and cellular biology at the University of California, said: “We can look at past events and actually reconstruct what the path we are on will be. It’s a great thing to be able to do.” Berkeley. “Although 50,000 years ago is a long time ago, having genetic data available from these samples really helps paint a more detailed picture.
The two research groups took different approaches to the study.
Moorjani’s group cataloged genomic information from 59 ancient and 275 modern humans who lived between 2,000 and 45,000 years ago. The researchers then analyzed how the distribution and length of Neanderthal DNA in those genomes changed over time.
They determined that the influx of Neanderthal genes into humans occurred about 47,000 years ago and lasted less than 7,000 years. These findings are consistent with archaeological evidence suggesting that Neanderthals and humans overlapped geographically when humans left Africa. Many scientists suspect that the two species crossed paths in the Middle East, but this has not been confirmed.
After interbreeding, natural selection retained some Neanderthal traits and discarded many more.
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Source: www.nbcnews.com
