Washington. What makes humans unique? Scientists have taken a new step towards solving this ancient mystery with a tool that could allow accurate comparisons between the DNA of modern humans and that of our extinct ancestors.
Only 7% of our genome is shared exclusively with other humans and not shared with our ancestors, according to a study published Friday by the journal Science Advances.
“It’s a very small percentage,” He said Nathan Schaefer, a computational biologist at the University of California and co-author of the study. “This kind of discovery is why scientists left behind the idea that we are so different from Neanderthals.”
The study uses DNA extracted from the fossil remains of Denisovans and Neanderthals dating between 40,000 and 50,000 years ago, as well as DNA from 279 modern humans from around the world.
Scientists already know that modern humans share DNA with Neanderthals, but different people share different parts of the genome. One of the goals of the new studies was to identify the genes unique to modern humans.
It’s a difficult statistical problem, he said, and the scientists have developed “a valuable tool that takes into account missing data in the ancient genome.” John Hawks, a paleontologist at the University of Wisconsin who was not involved in the study.
Scientists have also discovered that a smaller portion of our genome – 1.5% – is unique to our species and is shared by all humans today. These sections of DNA may contain the most important clues about what really distinguishes modern humans.
“We can determine that these regions of the genome are rich in genes involved in neural development and brain function,” he said. Richard Green, a computational biologist on the campus of the University of California, Santa Cruz, and one of the study’s authors.
In 2010, Green helped produce the first primary sequence of the Neanderthal genome. Four years later, a geneticist Joshua Aki He co-wrote a study that showed modern humans had traces of Neanderthal DNA. Since then, scientists have continued to refine techniques for extracting and analyzing genetic material from fossils.
Better tools allow us to ask more and more detailed questions about human history and development.Aki, who is now at Princeton University and was not involved in the study, said. Aki praised the methodology of the study.
However, Alan TempletonA population geneticist at the University of Washington, on campus in St. Louis, questioned the authors’ assumptions that changes in the human genome are randomly distributed, rather than aggregated around specific hubs within the genome.
Results confirm ‘we are a very small species’Aki said. “Not long ago, we shared the planet with other human races.”
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