At most, just 7% of the human genome is unique to our species. We share most genes with Neanderthals, Denisovans, and other ancestors.

Neanderthal
An employee of the Natural History Museum in London looks at model of a Neanderthal male in his twenties, which is on display at the museum’s “Britain: One Million Years of the Human Story” exhibition, September 2014.

Humans like to think they’re special, but our genes suggest that’s far from the case.

No more than 7% of the human genome is unique to Homo sapiens, according to a study published Friday in the journal Science Advances.

We share the remaining chunks of our genetic material with other human ancestors, or hominins, including our Neanderthal cousins and the Denisovans first discovered in east Asia.

“The evolutionary family tree shows there are regions of our genome that make us uniquely human,” Richard Green, director of the paleogenomics lab at the University of California, Santa Cruz and co-author of the new study, told Insider. “Now we have a catalog of those, and it’s a surprisingly small fraction of the genome.”

Anthropologists already knew that our hominin ancestors all interacted and interbred – exchanging genes and stone technologies that altered the course of our species’ evolution. But these new findings further underscore just how frequently that intermingling happened in the last 300,000 years or so, since the first known population of modern humans emerged.

“More or less everywhere we look, admixture is not the exception at all, but rather the rule,” Green said.

Genetic evidence suggests our ancestors interbred with mysterious hominins

Neanderthal family
An exhibit shows the life of a neanderthal family in a cave in the new Neanderthal Museum in the northern town of Krapina, Croatia, February 25, 2010.

To construct a hominin family tree, Green’s team sequenced and compared genomes from 279 modern humans – sampled from people all over the world – to ancient genomes from one Denisovan and two Neanderthals. Then, the researchers used a computer algorithm to determine out how each of those individuals are related to each other.

The analysis tool, which Green said took years to develop, helped them distinguish what parts of the human genome are devoid of admixture – meaning these sets of genes aren’t seen in Neanderthals or Denisovans.

The algorithm also highlighted what genes humans inherited from an even older ancestor, one that lived 500,000 years ago or so, that eventually gave rise to our species as well as Neanderthals and other hominins.

The study results suggest mysterious populations of human ancestors that scientists haven’t even discovered yet may have interbred with Neanderthals and Denisovans before these species mixed with modern humans, Green added.

Genes unique to humans are related to our brain development

denisovan mtDNA lab work
A scientist at work in a laboratory at the Max Planck Institute for Evolutionary Anthropology analyzing ancient DNA.

Researchers have already identified many of the human genes that resulted from cross-species trysts, but this is the first study to pinpoint what regions of genes were completely devoid of admixture, according to Green.

His group found these uniquely human regions of our genome were “incredibly enriched for genes that have to do with neural development,” Green said.

While Neanderthals have similarly large, if not larger, heads than humans do, that cranium size tells us little about how well their brains work compared to ours.

“Now we know human-specific stuff has to do with brain function,” Green said.

And most of these uniquely human genes came out during two distinct bursts of evolution – one that happened 600,000 years ago and another 200,000 years ago – the study found.

One of those evolutionary waves could’ve laid the genetic groundwork for human communication, Green said.

“It’s extremely tempting to speculate that one or more of these bursts had something to do the incredibly social behavior humans have – mediated in large part by our expert control of speech and language,” he said.

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‘Dragon Man,’ a mysterious new human species found in China, could be a closer relative of ours than Neanderthals

Homo longi dragon man
An artist’s concept of Homo longi, or “Dragon Man.”

About 146,000 years ago, a hunter died in the forests of what is now northern China. His skull remained almost perfectly preserved in sediment until bridge builders in Harbin found it in 1933.

At that time, Harbin was occupied by Japan, so a Chinese worker hid the skull in an abandoned well, where it remained for 85 years. The worker told his grandson about the hidden bone, now known as the Harbin cranium, and three years ago it finally made its way to anthropologists at the Hebei GEO University.

A trio of papers published Friday reveal that the skull belonged to a previously unknown species of human ancestor, called Homo longi.

“Because the Harbin fossil is so well preserved and informative, it is one of the most important finds so far for the last 500,000 years of human evolution,” Chris Stringer, an anthropologist at the Natural History Museum in London who co-authored the studies, told Insider.

Stringer’s team nicknamed this new hominin species “Dragon Man,” after the province where it was found: Heilongjiang, which translates to “dragon river.”

According to the new research, “Dragon Man” could be the closest known relative of modern humans – closer than Neanderthals, the group to which that title previously belonged.

‘Dragon Man’ might have interbred with ancient humans

Homo longi dragon man
Skulls of different human ancestors uncovered in China so far – the “Dragon Man” skull is on the far right.

According to the new studies, the Harbin cranium came from a 50-year-old male. The analysis also showed that Homo longi had a brain size comparable to that of modern humans, though parts of its skull resemble those of more ancient hominins.

As shown in the video below, Homo longi’s skull is massive and has a flatter shape, with square eye sockets, thick eyebrow ridges, and oversized teeth. These are characteristics more typical of Neanderthals, and they suggest that “Dragon Man” was relatively large. From the skull’s size, researchers think the species had adapted to survive in harsh environments.

“Like Homo sapiens, they hunted mammals and birds, and gathered fruits and vegetables, and perhaps even caught fish,” Xijun Ni, a paleoanthropologist at the Hebei GEO University who co-authored the studies, said in a release.

During the period 146,000 years ago, known as the Middle Pleistocene, various human ancestors crossed back and forth between Africa, Asia, and Europe. Modern humans were already living in western Asia, including the Arabian Peninsula, so in their eastern migration, they could have crossed paths with the “Dragon Man.”

“We don’t know if this population survived long enough to meet Homo sapiens, but they may well have done. If Neanderthals could interbreed with modern humans, then I’m sure that the Harbin group could too,” Stringer said.

Humanity’s closest relative?

Neanderthal
An employee of the Natural History Museum in London looks at model of a Neanderthal male in September 2014.

To determine whether Homo longi was more like Homo sapiens or Neanderthals, the researchers measured more than 600 parts of the Harbin skull, then compared the data to 95 other hominin skulls. A computer analysis revealed that “Dragon Man” was likely closer on the evolutionary tree to modern humans than to Neanderthals – meaning the species shared a more recent common ancestor with us.

“We found our long-lost sister lineage,” Ni said.

Stringer thinks that Homo longi – along with other hominin fossils previously found in China that had not been assigned a species – is part of a distinct population of human ancestors that thrived in East Asia during the Middle Pleistocene.

Homo longi dragon man
An illustration of Homo longi, or “Dragon Man,” a new human ancestor discovered in China.

However, Ian Tattersall, an anthropologist with the American Museum of Natural History who was not involved in the research, told Insider that he’s unsure Homo longi is really a sister lineage to modern humans. That’s because skulls from Homo sapiens have distinct foreheads, and the bones that make up the face are retracted from the forehead, Tattersall said. He thinks “Dragon Man” is missing that characteristic.

“I’d reserve judgement on the claim of a particularly close relationship with Homo sapiens,” he said.

Tattersall said he doesn’t have a problem with assigning the skull to a new species, though.

‘Dragon Man’ could be a Denisovan

denisovan
A portrait of a juvenile female Denisovan.

It’s possible, Stringer said, that Homo longi is actually a member of the Denisovan population – a human ancestor that lived in Asia from 500,000 to 30,000 years ago. If that were the case, he added, “then we know that they did interbreed with both Neanderthals and our species, and some of the Harbin group’s DNA could still be in some Homo sapiens populations today.”

Homo longi dragon man
An illustration of Homo longi, or “Dragon Man.”

To investigate that possibility, researchers could collect ancient DNA from the skull for further testing.

“But as the extraction process is somewhat destructive, it needs to be considered very carefully for this precious fossil,” Stringer said.

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A human ancestor previously unknown to science lived alongside ancient humans and Neanderthals – and they all interbred

Nesher Ramla Homo
The partial skull and jaw bone of a newly discovered human ancestor named Nesher Ramla homo.

  • Scientists uncovered a new species of human ancestor named the Nesher Ramla homo in a sinkhole.
  • This ancestor lived between 140,000 and 120,000 years ago in Israel and Arabia alongside humans.
  • New research suggests Nesher Ramla homo interbred with humans, as well as our Neanderthal cousins.
  • See more stories on Insider’s business page.

The eastern Mediterranean coast was a crowded place 120,000 years ago.

By that time, Homo sapiens – anatomically modern humans – had migrated out of Africa and settled in modern-day Israel and Arabia. Meanwhile, Neanderthals – our genetic cousins – had started to thrive in Eurasia.

Now, new research reveals that a third human ancestor was hunting and gathering in the same landscape. Two studies published Thursday in the journal Science describe a previously unknown hominin called the Nesher Ramla homo. The group not only shared tools and technology with their neighbors, they also interbred.

“They lived together and interacted with another,” Rachel Sarig, an anthropologist from Tel Aviv University and co-author of the new studies, told Insider.

Nesher Ramla Homo
A virtual reconstruction of the Nesher Ramla lower jaw bone.

Sarig and her colleagues uncovered a partial jaw bone, which they pieced together from 17 fragments like a puzzle, deep in a sinkhole at an Israeli site called Nesher Ramla – hence the ancestor’s name. There were also chunks of skull and a tooth belonging to the same individual.

Notably, the human ancestor had no chin – a feature distinct to Homo sapiens – and a flatter, squatter head. Those features suggest Nesher Ramla was a more ancient species than the region’s other occupants.

“It was some kind of pre-Neanderthal,” Sarig said.

The team had expected the bones to belong to a modern human.

“Homo sapiens were the dominant population in the Levant” between 100,000 and 200,000 years ago, Sarig said. “We were very surprised when we started looking at the fossils, and it was clear right away that Nesher Ramla was not the same.”

A sinkhole in the Judean Hills

Nesher Ramla Homo
The Nesher Ramla sinkhole in Israel, west of Jerusalem.

The discovery was a decade in the making. In 2011, workers were expanding a limestone quarry in the Judean Hills – between Israel’s Mediterranean coast and Jerusalem – when they found a huge sinkhole.

In sediment about 25 feet down, Sarig’s team uncovered animal teeth and bones, flint stone tools, and the Nesher Ramla bones. They suspect the sinkhole was an ancient watering hole, where animals came to drink and our human ancestors gathered to butcher game.

The researchers calculated that the animal teeth and flint were between 120,000 and 140,000 years old, suggesting Nesher Ramla homo lived then, too. But Hila May, a co-author of the new studies, told Insider that it’s possible this prehistoric human started occupying the area up to half a million years ago.

Nesher Ramla Homo
The patch of sediment inside the Nesher Ramla sinkhole where scientists excavated the fossils.

Typically, hominins that lived during the Middle Pleistocene era in Israel, as Nesher Ramla homo did, are classified as part of the species Homo heidelbergensis. These ancestors are characterized by their use of fire to make tools and cook. But the authors of the study chose not to put this new human in that species, since its anatomical features do not align closely.

Still, May said this ancestor had a very similar way of life to Neanderthals and Homo sapiens.

“They were hunter-gatherers living in small groups, hunting animals like rhinos, horses, and deer,” she said, adding that Nesher Ramla were “not very different in their abilities from other groups.”

Interbreeding among human ancestors

Neanderthal
An artist’s conception of a Neanderthal.

The new study suggests that once Neanderthals migrated to Europe about 100,000 years ago, the Nesher Ramla group played a key role in shaping what they looked like and how they lived.

The new discovery might also solve a genetic mystery. Previous research found that some Neanderthals from the Middle Pleistocene era have genes that come from Homo sapiens. But these modern humans didn’t arrive in Europe until about 45,000 years ago – long after the Neanderthals.

nesher ramla
A stone tool found in the Nesher Ramla sinkhole.

So if Nesher Ramla interbred with both Neanderthals and modern humans in the Levant before Neanderthals expanded west, that could explain the migration of the genes.

“We needed some explanation how Homo genes got to Europe before Homo got there,” May said.

And the three hominins did more than just interbreed – evidence from the sinkhole also suggests they shared tool-making technologies, using the same types of flint tools made in the same way.

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