It has always been a mystery that what makes humans unique, and now scientists have found an answer to it with a new tool, that may allow for more precise comparisons between the DNA of modern humans and that of our extinct ancestors.
According to a study published in the journal Science Advances, it was found that just 7 percent of our genome is uniquely shared with other humans, and not shared by other early ancestors.
Mr. Nathan Schaefer, a University of California computational biologist and co-author of the new paper said that it is a pretty small percentage, “this kind of finding is why scientists are turning away from thinking that we humans are so vastly different from Neanderthals.”
The research draws upon DNA extracted from fossil remains of now-extinct Neanderthals and Denisovans dating back to around 40,000 or 50,000 years ago, as well as from 279 modern people from around the world.
Scientists already know that modern people share some DNA with Neanderthals, but different people share different parts of the genome. One goal of the new research was to identify the genes that are exclusive to modern humans.
The researchers also found that an even smaller fraction of our genome, just 1.5 percent, is both unique to our species and shared among all people alive today. Those slivers of DNA may hold the most significant clues as to what truly distinguishes modern human beings.
“We can tell those regions of the genome are highly enriched for genes that have to do with neural development and brain function,” said Mr. Richard Green, computational biologist at the University of California, Santa Cruz and co-author of the paper.
In 2010, Mr. Green helped to produce the first draft sequence of a Neanderthal genome. Later, geneticist Mr. Joshua Akey co-authored a paper showing that modern humans carry some remnants of Neanderthal DNA. Since then, scientists have continued to refine techniques to extract and analyze genetic material from fossils.
“Better tools allow us to ask increasingly more detailed questions about human history and evolution,” said Mr. Akey, who is now at Princeton and was not involved in the new research. He praised the methodology of the new study.
However, Mr. Alan Templeton, a population geneticist at Washington University in St Louis, raised questions against the authors’ assumption that changes in the human genome are randomly distributed, rather than clustered around certain hotspots within the genome.
