- A new study shows that only between 1.5% and 7% of the human genome is unique to our species.
- Neanderthals, Denisovans and other ancestors moyang It shares most of the same genes found in modern humans.
- Unique genes are involved in brain development, which may set our species apart.
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Humans like to think they are special, but our genes show that this is far from true.
No more than 7% of the human genome is unique to Homo sapiens, according to a lesson It was published Friday in the journal Science Advances.
We share the rest of our genetic material with other human ancestors, or hominids, including our Neanderthal and Denisovan cousins who were first discovered in East Asia.
“The evolutionary family tree suggests that there are regions in our genome that make us uniquely human,” Richard Green, director of the paleobiology laboratory at the University of California, Santa Cruz and co-author of the new study, told Insider. “Now we have the index, which is a surprisingly small part of the genome.”
Anthropologists already know that our ancestors were hominids They all react and multiply – Gene exchange and stone technology that have changed the course of evolution of our species. But the new findings further underscore how often such mixing has occurred in the last 300,000 years or so, since the appearance of the first known group of modern humans.
“A little bit wherever we look, mixing is not the exception at all, but the rule,” Green said.
Genetic evidence shows that our ancestors interbred with mysterious hominins
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An exhibition showing the life of a Neanderthal family in a cave at the Neo-Neanderthal Museum in the northern city of Krapina, Croatia, February 25, 2010.
Reuters / Nikola Sulic
To build a hominin family tree, Greene’s team sequenced and compared the genomes of 279 modern humans — samples from people from around the world — with the genomes of an ancient Denisovan and two Neanderthals. Next, the researchers used a computer algorithm to determine how each of these individuals related to one another.
The analysis tool, which Green says took years to develop, helps distinguish which parts of the human genome are free of mix-ups – meaning that this combination of genes was not seen in Neanderthals or Denisovans.
The algorithm also highlights the genes humans inherited from their older ancestors, who lived about 500,000 years ago, and that eventually gave rise to our species as well as Neanderthals and other hominins.
Green adds that the results suggest that a mysterious group of human ancestors that scientists have yet to discover may have interbred with Neanderthals and Denisovans before these species mixed with modern humans.
Unique human genes linked to the evolution of our brain
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A scientist working in a laboratory at the Max Planck Institute for Evolutionary Anthropology analyzes ancient DNA.
Max Planck Institute for Evolutionary Anthropology
Researchers have identified many human genes resulting from cross-species efforts, but this is the first study to precisely identify gene regions that are completely free of mixing, according to Green.
Green said his group found that this unique region of our genome is “very rich in genes involved in neurodevelopment.”
While Neanderthals had heads that were as large, if not larger, than humans, the size of their skulls doesn’t tell us much about how well their brains worked compared to ours.
“We now know that things in humans have to do with brain function,” Green said.
The study found that most of these unique human genes emerged during two different evolutionary periods – one that occurred 600,000 years ago and the other 200,000 years ago.
One of those evolutionary waves could lay the genetic basis for human communication, Green said.
“It’s tempting to speculate that one or more of these impulses share the astonishing social behavior of humans — much of which is mediated by our speech and language control experts,” he said.
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