2021-02-17 18:34:17 UTC
Genes inherited from NEANDERTHALS slash the risk of severe Covid-19 by 22% by
triggering production of a virus-fighting enzyme, study finds
*Researchers compared the DNA of 2,200 Covid-19 patients with Neanderthals
*People with Neanderthal stretch of DNA are 22% less at risk of severe infection
*Another piece of Neanderthal DNA on chromosome 3 actually increases risk
*1 in 8 has the disadvantageous Neanderthal DNA on chromosome 3, whereas around
1 in 3, and up to half, of Eurasians have beneficial chromosome 12 DNA
Three genes inherited from Neanderthals slash the risk of severe Covid-19 by 22
per cent, a new study has revealed.
The genes sit next to each other on chromosome 12, and this large chunk of
genetic material includes 75,000 individual pieces of DNA.
Researchers compared the DNA of 2,200 Covid-19 patients from around the world
with the genes of three Neanderthals that lived 50,000, 70,000 and 120,000 years
They found people with Neanderthal versions of the genes OAS1, OAS2 and OAS3
were less likely to develop severe symptoms after infection with the
These genes produce enzymes which specifically target invading RNA viruses, and
the Neanderthal version is thought to be more potent.
Professor Hugo Zeberg and Dr Svante Pääbo from the Karolinska Institutet in
Stockholm and the Max Planck Institute for Evolutionary Anthropology in Leipzig,
respectively, conducted the study.
Previous research has found eight genetic locations spread across five
chromosomes (3, 6, 12, 19 and 21) which are 'associated with risk of requiring
intensive care upon SARS-CoV-2 infection'.
However, the new analysis shows only those found at chromosome 3 and 12
originate from cross-species trysts between Homo sapiens and Neanderthals.
The chromosome 3 gene was the subject of previous research from the same team of
It revealed the Neanderthal version, which is present in around one in eight
people today, actually doubles the risk of needing intensive care if a person
But the stretch of Neanderthal DNA on chromosome 12 is more common.
It was present in around one in ten humans that lived more than 20,000 years
ago, and then increased to around 15 per cent up to 10,000 years ago.
The researchers estimate it continued to become more dominant, with around a
third of people who lived between 3,000 and 1,000 years ago having it.
'Intriguingly, the current allele frequency in Eurasia is around 30 per cent,
suggesting that the Neandertal haplotype may have increased in frequency
relatively recently,' the researchers write in their paper.
They add: 'It is present in populations in Eurasia and the Americas at carrier
frequencies that often reach and exceed 50 per cent.'
Dr Pääbo says it is 'striking' that two Neanderthal variants can have such
drastically different impacts on human immune response to SARS-CoV-2 infection.
'This shows that our heritage from Neanderthals is a double-edged sword when it
comes to our response to SARS-CoV-2,' adds Professor Zeberg.
The researchers believe the location of the Neanderthal DNA on chromosome 12 is
key, as it includes three genes (OAS1, OAS2 and OAS3) which play a critical role
in fighting infection.
Specifically, they help produce enzymes which target and destroy invasive RNA,
such as SARS-CoV-2 which causes Covid-19.
The new research, published in the journal PNAS, also found the Neanderthal
variant makes more virus-fighting enzymes than the ancestral Homo sapien
'One may speculate that, when modern humans encountered new RNA viruses outside
Africa, the higher enzymatic activity of the ancestral variants that they
acquired through genetic interactions with Neandertals may have been
advantageous,' the researchers write.
'Intriguingly, there is evidence that the Neanderthal-like OAS haplotype may
have recently increased in frequency in Eurasia, suggesting that selection may
have positively affected the Neandertal-derived OAS locus in the last
Due to the ancient migratory patterns of Neanderthals and the fact they sparsely
inhabited Africa before going extinct, very little Neanderthal DNA is seen in
people living in sub-Saharan Africa today.
In fact, the researchers say the Neanderthal Covid-fighting genes are 'almost
completely absent' from these populations.
'In the Americas, it occurs in lower frequencies in some populations of African
ancestry, presumably due to gene flow from populations of European or Native
American ancestry,' they add in the paper.
The latest study backs up previous findings from a separate team of researchers
from Canada, which also came to the conclusion the OAS1 gene reduces the risk of
serious illness, hospitalisation and death from Covid-19.
Although they did not look at the gene's origin, they did find five genes which
increase the odds of severe infection.
Four of these genes TYK2 and DPP9 on chromosome 19; IFNAR on chromosome 21
and OAS on chromosome 12 were also studied by the latest study.
Neanderthals and Homo erectus, both cousins of modern-day humans, went extinct
due to sudden, and unexpectedly intense, bouts of climate change.
Scientists have long sought to understand the fate of our long-lost brethren,
and previous studies have indicated climate change likely plays a major role.
Computer analysis, published today, reveals the hominins failed to adapt to a
rapidly changing climate.
Researchers investigated temperature, rainfall and other data over the last five
million years to get a gauge of the climate for every 1,000-year window.
They also modelled the evolution of Homo species' through time by plundering an
extensive database of more than 2,750 fossils.
The analysis revealed three Homo species - H. erectus, H. heidelbergensis and H.
neanderthalensis - lost most of their 'climatic niche' just before going
Climactic niche describes a locale where conditions are just right for the
species to survive, not too hot, dry, cold or barren.
According to the researchers, Neanderthals were wiped out around 40,000 years
ago and Homo erectus went extinct 70,000 years before that.