At most, 7% of the human genome is unique to our species


Will Oliver/PA Images

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…”

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

Of course I find the research fascinating. Not that the admixture of Neanderthal and Denisovan genes [and others] diminishes or alters the Homo Sapiens characteristics. Still, I reflect upon what colors my emotions and judgement from my Neanderthal ancestors. I have 3% directly identifiable genetic material from that stream of evolution.

Stone circles 176,500 years old – constructed by Neanderthals


Etienne Fabre/SSAC

Approximately 176,500 years ago, in a cave in what is now called France, Neanderthals cut 400 pieces of stalagmite into regular lengths and arranged them in two circles and four piles. In 1990, a teenager and a group of local cavers rediscovered them. Only now, though, have scientists estimated just how old they are—dating well beyond the history of Homo sapiens in this area.

This is one of the earliest examples of construction ever found, and the first example of Neanderthal construction that scientists have dated. It shows that these early homonins explored underground and could use fire and reveals an unknown aspect of their culture. It’s not clear what the circle of stones was used for, but it’s possible it had a ritual function, since there’s no evidence that anyone actually lived in the cave.

The more we learn about Neanderthals, the smarter and more complex was their lifestyle, using fire, creating design art. All before the newer iteration of humans expanded into regions already populated by our older cousins.

Unaffected by Covid? Maybe thank your Neanderthal ancestors

People who survive a bout of Covid-19 with mild symptoms or even no symptoms may be able to thank their Neanderthal ancestors, a new study suggests.

Researchers found a genetic mutation that reduces the risk of severe Covid-19 infection by about 22%. It was found in all the samples they took of Neanderthal DNA, and in about 30% of samples from people of European and Asian origin.

The genetic region involved affects the body’s immune response to RNA viruses such as the coronavirus, as well as West Nile virus and hepatitis C virus, the researchers reported Tuesday in the Proceedings of the National Academy of Sciences…

The finding could help explain why Black patients are so much more likely to suffer severe coronavirus disease. Neanderthals, who went extinct about 40,000 years ago, lived alongside and sometimes interbred with modern humans in Europe and Asia but not in Africa, and people of purely African descent do not carry Neanderthal DNA. Studies estimate that about 2% of DNA in people of European and Asian descent can be traced back to Neanderthals.

RTFA. Details on the research. And it’s certainly interesting to our household. Genetic analysis shows my wife with about 2% Neanderthal DNA. I’m actually at about 3%.

Research: DNA shows girl had one Denisovan parent, one Neanderthal

DNA from just a single cave in Siberia revealed that it had been occupied by two archaic human groups that had interbred with the newly arrived modern humans. This included both the Neanderthals, whom we knew about previously, and the Denisovans, who we didn’t even know existed and still know little about other than their DNA sequences. The DNA also revealed that one of the Denisovans had a Neanderthal ancestor a few hundred generations back in his past…

Now, the same cave has yielded a bone fragment that indicates the interbreeding may have been common. DNA sequencing revealed that the bone fragment’s original owner had a mom that was Neanderthal and a father who was Denisovan. The fact that we have so few DNA samples from this time and that one is the immediate product of intermating gives us a strong hint that we should expect more examples in the future.

The Denisova Cave sits within Russia near its borders with China, Kazakhstan, and Mongolia. It appears to have conditions that favor the preservation of ancient DNA, as bones from the site have yielded high-quality genomes from both Neanderthals and Denisovans. It does not seem to have favored the preservation of skeletons themselves, as most material has been fragmentary; all we know about the appearance of Denisovans comes from a molar and a small finger bone, though dating indicates they occupied the cave more than 30,000 years after the Neanderthal.

Fascinating stuff…even if you’re already beyond fundamentalist fairy-tales.

Cave dweller menus were limited by what’s available – from Woolly rhino to mushrooms

❝ Eating like a caveman meant chowing down on woolly rhinos and sheep in Belgium, but munching on mushrooms, pine nuts and moss in Spain. It all depended on where they lived, new research shows.

❝ Scientists got a sneak peek into the kitchen of three Neanderthals by scraping off the plaque stuck on their teeth and examining the DNA. What they found smashes a common public misconception that the caveman diet was mostly meat. They also found hints that one sickly teen used primitive versions of penicillin and aspirin to help ease his pain.

The dental plaque provides a lifelong record of what went in the Neanderthals’ mouths and the bacteria that lived in their guts, said study co-author Alan Cooper, director of the Australian Centre for Ancient DNA in Adelaide.

“It’s like a fossil,” he said.

❝ While past studies showed varied Neanderthal diets, genetic testing allowed researchers to say what kind of meat or mushrooms they ate, Cooper said. The 42,000-year-old Belgian Neanderthal’s menu of sheep and woolly rhino reflected what roamed in the plains around the Neanderthal’s home, he said. The research is in Wednesday’s journal Nature…

There were no signs of meat in the diet of the two 50,000-year-old Spanish Neanderthals, but calling them vegetarians would be a stretch, Cooper said. Their own bones showed that they were eaten by cannibals.

I don’t doubt that the politicians, priests and pundits of the time provided believable reasons for every part of life – from diet to ritual – even if they were crap. Part of the job description that hasn’t changed.

Some Pacific Islanders have DNA of a previously unknown human ancestor

papua-new-guinea

❝ Most everyone knows that the islands of the South Pacific are some of the most remote and unique places on Earth, but a new study reveals just how unique they really are.

…Researchers have found traces of a previously unknown extinct hominid species in the DNA of the Melanesians, a group living in an area northeast of Australia that encompasses Papua New Guinea and the surrounding islands.

❝ A computer analysis suggests that the unidentified ancestral hominid species found in Melanesian DNA is unlikely to be either Neanderthal or Denisovan, the two known predecessors of humankind to this point.

❝ Archaeologists have found many Neanderthal fossils in Europe and Asia, and although the only Denisovan DNA comes from a finger bone and a couple of teeth discovered in a Siberian cave, both species are well represented in the fossil record.

But now genetic modeling of the Melanesians has revealed a third, different human ancestor that may be an extinct, distinct cousin of the Neanderthals.

“We’re missing a population, or we’re misunderstanding something about the relationships,” said researcher Ryan Bohlender…“Human history is a lot more complicated than we thought it was.”

One of the confounding delights of scientific methods becoming more accurate, more capable of revealing features contributing to a much larger system – the analysis can become more complex and expand the search for knowledge at the same time.

Genetic evidence of modern human DNA in a Neanderthal — Huh? Wha?

Using several different methods of DNA analysis, an international research team has found what they consider to be strong evidence of an interbreeding event between Neanderthals and modern humans that occurred tens of thousands of years earlier than any other such event previously documented.

…In NATURE the team publishes evidence of interbreeding that occurred an estimated 100,000 years ago. More specifically the scientists provide the first genetic evidence of a scenario in which early modern humans left the African continent and mixed with archaic (now-extinct) members of the human family prior to the migration “out of Africa” of the ancestors of present-day non-Africans, less than 65,000 years ago.

❝ “It’s been known for several years, following the first sequencing of the Neanderthal genome in 2010, that Neanderthals and humans must have interbred,” says Professor Adam Siepel, a co-team leader and Cold Spring Harbor Laboratory (CSHL) quantitative biologist. “But the data so far refers to an event dating to around 47,000-65,000 years ago, around the time that human populations emigrated from Africa. The event we found appears considerably older than that event…”

❝ “One very interesting thing about our finding is that it shows a signal of breeding in the ‘opposite’ direction from that already known,” Siepel notes. “That is, we show human DNA in a Neanderthal genome, rather than Neanderthal DNA in human genomes.”

This finding, the result of several kinds of advanced computer modeling algorithms comparing complete genomes of hundreds of contemporary humans with complete and partial genomes of four archaic humans, has implications for our knowledge of human migration patterns.

The article proceeds from this point to examination of several intertwining themes of interbreeding between different strands of the evolutionary vines that tie us all to our species. A worthwhile read.

It also validates a theme long held as strong among my Highland antecedents – whether critical or not – that our species [and any near relative] is ready to have sex with anyone willing to stand still long enough to enjoy it.

DNA yields secrets of early humans


Universal Human

DNA analysis of a 45,000-year-old human has helped scientists pinpoint when our ancestors interbred with Neanderthals…The genome sequence from a thigh bone found in Siberia shows the first episode of mixing occurred between 50,000 and 60,000 years ago.

The male hunter is one of the earliest modern humans discovered in Eurasia.

The study in Nature journal also supports the finding that our species emerged from Africa some 60,000 years ago, before spreading around the world…

The work of Prof Svante Paabo, from the Max Planck Institute in Leipzig, Germany, is rewriting the story of humanity. Prof Paabo and his colleagues have pioneered methods to extract DNA from ancient human remains and read its genetic code.

From this sequence, the scientist has been able to decipher an increasingly detailed story of modern humans as they spread across the globe.

“The amazing thing is that we have a good genome of a 45,000-year-old person who was close to the ancestor of all present-day humans outside Africa…”

Prof Paabo has analysed DNA from part of a leg bone of a man that lived in Western Siberia around 45,000 years ago. This is a key moment at the cross roads of the world, when modern humans were on the cusp of an expansion into Europe and Asia.

The key finding was that the man had large, unshuffled chunks of DNA from a now extinct species of human, Neanderthals, who evolved outside of Africa.

“Our analysis shows that modern humans had already interbred with Neanderthals then, and we can determine when that first happened much more precisely than we could before…”

Prof Paabo’s 45,000-year-old man seems to have lived at a point that was both geographically, and in time, a crossroads for humanity…”This does seem to mark a watershed where modern humans were pushing the boundaries further and further in their dispersal out of Africa,” according to Prof Chris Stringer.

Prof Paabo also compared the DNA of the man living 45,000 years ago with those living today. He found that the man was genetically midway between Europeans and Asians – indicating he lived close to the time before our species separated into different racial groups.

Fascinating stuff. I’ve had DNA tests that determined the coarser texture of how my ancestors spread from their African genesis into the steppes of Central Asia. Eventually ending up traveling west to the Scottish Highlands and, then, sweeping back east to the Danube before retreating to stay in Scotland.

Neanderthal clue to cancer origins


Abnormal Neanderthal bone (above) compared with normal Neanderthal specimen (below)

A Neanderthal living 120,000 years ago had a cancer that is common today, according to a fossil study.

A fossilised Neanderthal rib found in a shallow cave at Krapina, Croatia, shows signs of a bone tumour…The discovery is the oldest evidence yet of a tumour in the human fossil record, say US scientists.

The research, published in the journal PLOS One, gives clues to the complex history of cancer in humans.

Until now, the earliest known bone cancers have been identified in ancient Egyptian remains from about 1,000-4,000 years ago.

It’s the oldest tumour found in the human fossil record,” Dr David Frayer, the University of Kansas anthropologist who led the US team, told BBC News.

“It shows that living in a relatively unpolluted environment doesn’t necessarily protect you against cancer, even if you were a Neanderthal living 120,000 years ago.”

The fossil was uncovered from an important archaeological site that has yielded almost 900 ancient human bones, along with stone tools…The tumour was diagnosed by a medical radiologist from X-rays and CT scans.

Although efforts to extract ancient DNA from the Neanderthal fossil have proved unsuccessful, the researchers hope other fossils may shed light on cancer in prehistoric humans.

Commenting on the study, Kat Arney, science information manager at Cancer Research UK, said: “Some people think that cancer is only a modern disease, but there’s evidence from fossils, bones and mummies that it’s actually many thousands of years old.

Opens up a whole new range of scary possibilities – but, I’m not even up to an educated guess on this narrow topic. So, I’ll shut up.