Washington. What makes human beings unique? Scientists have taken a new step to solve that old mystery with a tool that allows for accurate comparisons between the DNA of modern humans and the DNA of our extinct ancestors.
Only 7% of our genes are shared exclusively with other humans, but have not been shared with our ancestors, according to a study published Friday in Scientific Advances magazine.
“This is a very small percentage”, he said Nathan Schaefer, A computational biologist and associate professor of research at the University of California. “This kind of discovery leaves scientists wondering why we are so different from Neanderthals.”
This study uses DNA extracted from fossils by Denisovan hominid and Neanderthal 40,000 to 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 individuals share different parts of the gene. One of the goals of the new study is to identify genes unique to modern humans.
This is a difficult statistical problem, and scientists have “developed a valuable tool for taking into account missing data on ancient genes,” he said. John Hawks, An archaeologist at the University of Wisconsin who is not involved in the study.
Scientists have also discovered that a small fraction of our gene – 1.5% – is unique to our species and is shared by all humans today. Those sections of the DNA may contain some of the most important clues about what really distinguishes modern humans.
“We can identify that these areas of the gene are highly enriched by genes associated with neurodevelopment and brain function,” he said. Richard Green, A computational biologist at the University of California, Santa Cruz Campus, who is one of the authors of the study.
In 2010, Green helped create the first preliminary sequence of the gene by Neanderthals. Four years later, the geneticist Joshua Ake He co-authored a study by Neanderthals showing that modern humans have traces of DNA. Since then, scientists have continued to refine techniques for extracting and analyzing genetic material from fossils.
“The best tools allow us to ask more and more detailed questions about human history and evolution”Aki, who now works at Princeton University, said he was not involved in the study. Ake praised the method of study.
However, Alan Templeton, A demographic geneticist at the University of Washington on the San Luis campus, questioned the authors’ assumptions that changes in the human genome are roughly distributed without clusters around certain axes within the gene.
The findings emphasize that “we are a very young species.”Said Ake. “Long ago, we shared the planet with other human descendants.”