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MODERN HUMAN HEALTH ISSUES MAY INFLUENCED BY NEANDERTHAL DNA

A 2014 study in the journal Nature tied several present-day human diseases — such as diabetes, Crohn's disease, lupus and cirrhosis — to Neanderthal DNA remnants. Severe COVID-19 has also been been found to have such a strong genetic connection with Neanderthals. [Source: Dr. Alakananda Dasgupta, Live Science, June 20, 2023]

After modern humans migrated out of Africa, researchers believe they encountered and interbred with Neanderthals in the Middle East around 60,000 years ago. As a result, modern humans of non-African descent share around 2 percent of their DNA with Neanderthals and DNA passed on from Neanderthals to modern humans appears to have influenced the health of modern humans living today. “Neanderthals contributed DNA to present-day people,” says Svante Paabo of the Max Planck Institute, “and this has physiological effects today, for example in immune defense, pain sensitivity, risk for miscarriages, and susceptibility to severe outcomes from COVID-19.”

Carl Zimmer wrote in the New York Times: “ Once Neanderthal DNA entered our gene pool, it spread down through the generations, long after Neanderthals became extinct. Most Neanderthal genes turned out to be harmful to modern humans. They may have been a burden on people’s health or made it harder to have children. As a result, Neanderthal genes became rarer, and many disappeared from our gene pool. But some genes appear to have provided an evolutionary edge and have become quite common. In May, 2020, scientists at the Max Planck Institute, discovered that one-third of European women have a Neanderthal hormone receptor. It is associated with increased fertility and fewer miscarriages. Other Neanderthal genes that are common today even help us fight viruses. When modern humans expanded into Asia and Europe, they may have encountered new viruses against which Neanderthals had already evolved defenses. We have held onto those genes ever since. [Source: Carl Zimmer, New York Times, July 6, 2020]

Daniel Weiss wrote in Archaeology magazine: “Many genes associated with diseases — in particular psychiatric and neurological disorders such as Alzheimer’s disease, autism, and schizophrenia — also appear to be activated in modern humans but not Neanderthals. Liran Carmel of Hebrew University says the activation of these genes may have produced an evolutionary catch-22: bestowing a benefit, perhaps by changing the wiring of our brains, but also introducing an increased risk of disease. [Source:Daniel Weiss, Archaeology magazine, January-February 2015]

Paul Jongko wrote in Listverse: “Depression, nicotine addiction, and heart attacks are some of the health problems that plague our society today. Though these diseases appear modern, new research from the Vanderbilt University and the University of Washington suggests that these illnesses could have originated from the Neanderthals. The co-author of the study, Joshua Akey, said, “You can blame your Neanderthal ancestry a little—but not too much—for whatever range of afflictions you have.” Researchers Akey and John Capra made the discovery after examining the medical records and genes of 28,000 people. The records allowed the scientists to determine the health conditions of the subjects, and their genes enabled them to find the DNA that was inherited from the Neanderthals. It was clear that the presence of Neanderthal DNA had slightly increased the subject’s health risks”. [Source: Paul Jongko, Listverse, May 14, 2016]

Neanderthal Passed on Thick Skin DNA to Humans

It seems likely that Neanderthal DNA that survives in modern humans helped them adapt to cold Europe by giving them thicker skin, researchers said. AFP reported: “Humans acquired Neanderthal DNA through interbreeding between 40 000 and 80 000 years ago which resulted in today's European and East Asian populations, scientists believe. Indigenous Africans have little or no Neanderthal DNA as their ancestors did not interbreed with Neanderthals, who lived in Europe and Asia. [Source: Mariette Le Roux, AFP, 30 January 2014 ^^]

“The latest research showed that the Neanderthal's DNA influence on humans was not evenly distributed across the human genome. Two separate studies, one in the British journal Nature and the other in US-based Science, reported finding concentrations of Neanderthal DNA in genes that influence skin and hair characteristics. The Nature team, which included scientists from Harvard, the Broad Institute in Cambridge and the Max Planck Institute for Evolutionary Anthropology in Germany, analysed and compared the genomes of 846 people of non-African heritage, 176 Africans, and a 50 000-year-old Neanderthal. The authors of the paper in Science, using statistical simulations with the genome sequences of 379 European and 286 East Asian individuals and one Neanderthal, came to a similar conclusion on our distant cousin's influence on human skin-related genes. ^^

“Among other things, these genes influence the production of keratin - a fibrous protein that lends toughness to skin, hair and nails and may have provided thicker insulation against a colder climate as homo sapiens moved northwards out of Africa, the authors of the Nature paper said. “Thus, Neanderthal alleles (gene variations) that affect skin and hair may have helped modern humans to adapt to non-African environments,” said the study. “It's tempting to think that Neanderthals were already adapted to the non-African environment and provided this genetic benefit to humans,” added co-author David Reich, a genetics professor at Harvard Medical School. ^^

“Recent research has concluded that humans trace about two percent of their genome to Neanderthals, but these claim to be the first studies to show the biological effect that the transfer has had on human development. Both studies found regions on the human genome that were devoid of Neanderthal DNA and concluded that certain genes must have been detrimental to humans and could not be tolerated. These Neanderthal-barren areas were mostly found on genes linked to functioning of the testes and the X chromosome, leading researchers to conclude the genetic exchange had threatened male fertility and had to be undone through a process of natural selection.” ^^

Neanderthals and Denisovans Strengthened Our Immune System?

Research from Stanford, the Max Planck Institute for Evolutionary Anthropology and the Institute Pasteur have suggested interbreeding with the Neanderthals strengthened the immune system of modern humans. Linda Marsa wrote in Discover: “When our ancestors mated with Neanderthals and Denisovans, a recently discovered archaic human group, they picked up some of their genes. Now researchers say that DNA inherited from these extinct hominins may have fortified the modern immune system. A team at Stanford University focused on human leukocyte antigen (HLA) class 1 genes, which play a vital role in rallying the immune system to fight off bacteria and viruses. Because diseases can be endemic to specific regions of the world, these genes exist in thousands of versions, known as alleles. [Source: Linda Marsa, Discover, December 22, 2011]

“To analyze the origin of these alleles, the scientists looked at bone marrow registries containing the HLA genes of millions of people from all parts of the globe. By comparing DNA from modern populations with the reconstructed genomes of Neanderthals and Denisovans, they discovered that several HLA variants from the archaic groups are still around. For example, the ancient gene for HLA-A, which helps the body resist viruses like Epstein-Barr, is present in half of all modern Europeans, more than 70 percent of Asians, and up to 95 percent of people in Papua New Guinea. Other ancient alleles are involved in the regulation of natural killer cells, essential for immune defense.

“Our ancestors’ liaisons with Neanderthals and Denisovans may have made them less susceptible to local infections, proposes Stanford immunologist Laurent Abi-Rached, giving them a survival advantage as they migrated out of Africa to Europe and Asia. “Breeding with our evolutionary cousins may have facilitated the spread of modern humans by preventing them from getting sick.”“

Neanderthals Gave Us Diabetes?

Paul Jongko wrote in Listverse: “Harvard geneticist David Altshuler and his colleagues suggested that modern humans might have gotten the diabetes mutations from Neanderthals. This discovery was made several years after the Max Planck Institute for Evolutionary Anthropology sequenced the DNA of a Neanderthal from a fossil. The researchers were quick to point out that their findings don’t necessarily prove that our extinct cousins suffered from diabetes. It just means that the mutations that cause type 2 diabetes, especially among Latinos and Asians, originated from them. [Source: Paul Jongko, Listverse, May 14, 2016]

“Altshuler and his colleagues made the discovery after examining the DNA of 8,000 residents of Mexico and Latin America. The people chosen for the research were of Native American and European descent. Though the link between modern-day diabetes and Neanderthals is fascinating, the researchers emphasized that the essence of their work is the development of new treatments that could potentially eradicate this global health problem.”

Researchers wrote in studies in Nature and Science that Neanderthals also conferred a risk for conditions like type-2 diabetes and Crohn's disease. The Nature team, which included scientists from Harvard, the Broad Institute in Cambridge and the Max Planck Institute for Evolutionary Anthropology in Germany, analysed and compared the genomes of 846 people of non-African heritage, 176 Africans, and a 50 000-year-old Neanderthal. The authors of the paper in Science, using statistical simulations with the genome sequences of 379 European and 286 East Asian individuals and one Neanderthal, came to a similar conclusion on our distant cousin's influence on human skin-related genes.[Source: Mariette Le Roux, AFP, 30 January 2014 ^^]

According to AFP: They “concluded that as much as 20 percent of the Neanderthal genome could be reconstituted today by adding up the totality of the DNA signature still lingering in modern humans. “If you look at enough individuals (we estimate about 2 000), you could theoretically identify all of the Neanderthal genome that still remains in modern humans,” Benjamin Vernot from the University of Washington's department of genome sciences, a co-author of the Science paper, told AFP. “Unfortunately, it's difficult to tell some Neanderthal DNA from human DNA, just because it's still pretty similar to ours. So while there might be 50 percent of the Neanderthal genome still floating around in modern humans, we were only able to identify 20 percent.” ^^

“The team had identified between 300 and 400 genes per individual that were at least partly Neanderthal, he said, but these were different from person to person. Both studies found regions on the human genome that were devoid of Neanderthal DNA and concluded that certain genes must have been detrimental to humans and could not be tolerated. These Neanderthal-barren areas were mostly found on genes linked to functioning of the testes and the X chromosome, leading researchers to conclude the genetic exchange had threatened male fertility and had to be undone through a process of natural selection.” ^^

Human-Neanderthal Gene Variance Involved in Autism

A structure that represents the biggest known genetic difference between humans and Neanderthals also predisposes humans to autism, a study by an international team of researchers led by University of Washington Medicine genome scientist Evan Eichler published in Nature in August 2016. Michael McCarthy wrote in the Medical Press: “The structure involves a segment of DNA on chromosome 16 that contains 28 genes. This segment is flanked by blocks of DNA whose sequences repeat over and over. Such stretches of duplicated DNA, called copy-number variants, are common in the human genome and often contain multiple copies of genes. Although most copy-number variants seem to have no adverse effect on health, some have been linked to disease. “However, when both strands of a segment of DNA are flanked by highly identical sequences, they can be susceptible to large copy-number differences, including deletion, duplication and other changes, during the process of cell division. In this case, deletion, which causes the loss of the segment's 28 genes, results in autism. [Source: Michael McCarthy, Medical Press, August 4, 2016]

“In the new study, researchers determined that this structure, located at a region on chromosome 16 designated 16p11.2, first appeared in our ancestral genome about 280,000 years ago, shortly before modern humans, Homo sapiens, emerged. This organization is not seen in any other primate – not chimps, gorillas, orangutans nor the genomes of our closest relatives, the Neanderthals and Denisovans. Yet today, despite the fact that the structure is a relatively new genetic change, it is found in genomes of humans the world over. "Most duplications in our genome are millions of years old, and the speed at which this structure transformed our genome is unprecedented," said co-author Eichler, a professor of genome sciences and an investigator of the Howard Hughes Medical Institute. "The wide and rapid distribution of these copy-number variants suggests the genes within the repetitive sections confer benefit that outweigh the disadvantages that come with the increased risk of autism in some offspring, should deletion occur."

“Copy-number variants may play an important role in human evolution because, as a species, we are relatively uniform genetically. "If you took two chimps out of the wild, they would have twice as many genetic differences in their genomes than you would see between two humans. And orangutans have three times as many differences. Having these structures means we have a way to radically restructure our genome over a very short time frame, bringing about changes that might otherwise take hundreds of millions of years of evolution to acquire – but at the cost of an increased risk of autism and other neuropsychiatric disorders," he said.

“One benefit of copy-number variants: They contain multiple copies of genes that can mutate and acquire new, potentially useful functions. Of particular interest to the researchers was a gene in the copy-number variants at 16p11.2 called BOLA2, multiple copies of which were found in both flanking regions. The BOLA2 protein in human cells appears to form a complex with another protein, called glutaredoxin 3, that allows the cells to capture iron more efficiently and make it available to proteins that require it. This effect appears to be most pronounced early in cell development. "This ability to help humans to acquire and use this essential element early in life might confer a significant enough benefit to outweigh the risk of having some offspring with autism," Eichler said.

“In addition to BOLA2, the mutations within the copy number variant regions appears to have created new protein formed by fusing two regions of the BOLA2 gene with three regions of another gene. This new gene may be the first completely new gene that distinguishes humans from our Neanderthal and ancient hominin cousins, Eichler said. Exactly what role the new protein it creates plays remains unknown. "We're going to work with other research teams to find out what it does but so far we haven't a clue."”

Neanderthal DNA Made Some People More Susceptible to COVID-19

A stretch of DNA linked to COVID-19 was passed down from Neanderthals 60,000 years ago, according to a new study.Carl Zimmer wrote in the New York Times: “Scientists don’t yet know why this particular segment increases the risk of severe illness from the coronavirus. But the new findings, which were posted online in July 2020 show how some clues to modern health stem from ancient history. “This interbreeding effect that happened 60,000 years ago is still having an impact today,” said Joshua Akey, a geneticist at Princeton University. [Source: Carl Zimmer, New York Times, July 6, 2020]

“This piece of the genome, which spans six genes on chromosome 3, has had a puzzling journey through human history, the study found. the study found. The variant is now common in Bangladesh, where 63 percent of people carry at least one copy. Across all of South Asia, almost one-third of people have inherited the segment. Elsewhere, however, the segment is far less common. Only 8 percent of Europeans carry it, and just 4 percent have it in East Asia. It is almost completely absent in Africa.

“It’s not clear what evolutionary pattern produced this distribution over the past 60,000 years. “That’s the $10,000 question,” said Hugo Zeberg, a geneticist at the Karolinska Institute in Sweden who was one of the authors of the new study. “Zeberg looked at chromosome 3 in an online database of Neanderthal genomes. He found that the version that raises people’s risk of severe COVID-19 is the same version found in a Neanderthal who lived in Croatia 50,000 years ago. “I texted Svante immediately,” Zeberg said in an interview, referring to Paabo.

Svante Paabo, the director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, said the DNA segment may account in part for why people of Bangladeshi descent are dying at a high rate of COVID-19 in the United Kingdom.

“It’s an open question whether this Neanderthal segment continues to keep a strong link to COVID-19 as Zeberg and other researchers study more patients. And it may take discoveries of the segment in ancient fossils of modern humans to understand why it became so common in some places but not others.

How COVID-19-DNA From Neanderthals Might Have Evolved

Carl Zimmer wrote in the New York Times: The six genes on chromosome 3 has had a puzzling journey through human history, One possibility is that the Neanderthal version is harmful and has been getting rarer overall. It’s also possible that the segment improved people’s health in South Asia, perhaps providing a strong immune response to viruses in the region. “One should stress that at this point this is pure speculation,” said Paabo. [Source: Carl Zimmer, New York Times, July 6, 2020]

“Tony Capra, a geneticist at Vanderbilt University thought it was plausible that the Neanderthal chunk of DNA originally provided a benefit — perhaps even against other viruses. “But that was 40,000 years ago, and here we are now,” he said.

Zeberg said that the 60,000-year journey of this chunk of DNA in our species might help explain why it’s so dangerous today. “Its evolutionary history may give us some clues,” Zeberg said. It’s possible that an immune response that worked against ancient viruses has ended up overreacting against the new coronavirus. People who develop severe cases of COVID-19 typically do so because their immune systems launch uncontrolled attacks that end up scarring their lungs and causing inflammation.

Neanderthal Gene That Protects Against Covid-19

A specific form of a protein passed down from Neanderthals protects against severe COVID-19, and medications that boost levels of this protein could potentially help treat the disease, according to a study reported on medRxiv in December 2020. Reuters reported: The protein, called OAS1, is involved in the body's response to viruses. People with higher levels of the Neanderthal-related form of OAS1 are less susceptible to COVID-19, and if they do become infected, they are at lower risk for hospitalization, intubation and death, the researchers found. [Source: Nancy Lapid, Reuters, December 22, 2020]

"This protective form of OAS1 is present in sub-Saharan Africans but was lost when the ancestors of modern-day Europeans migrated out of Africa. It was then re-introduced into the European population through mating with Neanderthals" who lived more than 40,000 years ago, said coauthor Brent Richards from the Jewish General Hospital and McGill University in Montreal. An earlier study linked a cluster of genes inherited from Neanderthals to higher risks of hospitalization from COVID-19. "These findings further implicate Neanderthal ancestry in COVID-19 severity," Richards said.

Mysterious 'Viking disease' linked to Neanderthal DNA

Neanderthal genes may be one cause of the disorder nicknamed the "Viking disease," in which fingers become frozen in a bent position, a new study finds according to a study published June 14, 2023 in the journal Molecular Biology and Evolution. The study found gene variants that were inherited from Neanderthals that dramatically increases the odds of developing the condition, officially called Dupuytren's disease. [Source: Dr. Alakananda Dasgupta, Live Science, June 20, 2023]

Dr. Alakananda Dasgupta wrote in Live Science: Dupuytren's disease is a crippling hand disorder named after a French surgeon, in which the fingers, typically the ring and little fingers, become permanently locked in a bent position. The condition is very common in Northern European countries where the Vikings settled, hence its nickname. It typically afflicts about 30 percent of men over 60 years in Northern Europe and seems to run in families. Treatment is mainly surgical, but recurrence is common. Although smoking, alcoholism, diabetes and anti-seizure medication can increase the odds of developing the disease, the exact cause has remained elusive.

The rarity of Dupuytren's disease among Africans led Dr. Hugo Zeberg, an evolutionary geneticist at Karolinska Institute in Stockholm, to wonder whether the genes tied to the disease came from Neanderthals, given that Africans have very limited Neanderthal ancestry. The researchers combined data from three large biobanks in the U.S., the U.K. and Finland comprising 7,871 cases and 645,880 controls in people of primarily European descent. They found 61 genetic variants tied to a higher risk of Dupuytren's disease.

Next, they compared these gene variants with the previously sequenced Neanderthal genome. To their surprise, they discovered that, of these 61 variants, three variants were of Neanderthal origin, of which two were very strongly linked to the disease. The Neanderthal gene most strongly linked to the disease, called EPDR1, sits on chromosome 7.

The link between Dupuytren's disease and these Neanderthal gene variants is especially strong. Two of the genetic mutations were the second- and third-most strongly associated with the odds of having the disease, respectively. "This is a very strong association," Zeberg told Live Science."It's an interesting study that sheds new light on the genetic basis of Dupuytren's disease," Serena Tucci, an anthropologist and evolutionary geneticist at Yale University who was not involved in the study, told Live Science in an email, adding that it's the first to tie the disease to remnant DNA from our close human relatives. People with roots outside Africa have about 2 percent Neanderthal DNA in their genome. So statistically, by random chance, you would expect Neanderthal DNA to collectively account for around 2 percent of the genetic risk of the disease. "But here we find that 8.4 percent is explained by Neanderthal gene flow," much more than is expected by chance alone, Zeberg noted. Image Sources: Wikimedia Commons

Text Sources: National Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Nature, Scientific American. Live Science, Discover magazine, Discovery News, Ancient Foods ancientfoods.wordpress.com ; Times of London, Natural History magazine, Archaeology magazine, The New Yorker, Time, Newsweek, BBC, The Guardian, Reuters, AP, AFP, Lonely Planet Guides, and various books and other publications.

Last updated April 2024