The ancient Neanderthal hand in severe COVID-19

Date:
September 30, 2020
Source:
Okinawa Institute of Science and Technology (OIST) Graduate
University
Summary:
Genetic variants that leave their carrier more susceptible to
severe COVID-19 are inherited from Neanderthals, a new study finds.



FULL STORY ========================================================================== [Early human scene, | Credit: (c) ginettigino / stock.adobe.com] Early
human scene, concept photo (stock image).

Credit: (c) ginettigino / stock.adobe.com [Early human scene, | Credit:
(c) ginettigino / stock.adobe.com] Early human scene, concept photo
(stock image).

Credit: (c) ginettigino / stock.adobe.com Close Since first appearing
in late 2019, the novel virus, SARS-CoV-2, has had a range of impacts
on those it infects. Some people become severely ill with COVID-19,
the disease caused by the virus, and require hospitalization, whereas
others have mild symptoms or are even asymptomatic.


========================================================================== There are several factors that influence a person's susceptibility to
having a severe reaction, such as their age and the existence of other
medical conditions. But one's genetics also plays a role, and, over
the last few months, research by the COVID-19 Host Genetics Initiative
has shown that genetic variants in one region on chromosome 3 impose a
larger risk that their carriers will develop a severe form of the disease.

Now, a new study, published in Nature, has revealed that this genetic
region is almost identical to that of a 50,000-year old Neanderthal from southern Europe.

Further analysis has shown that, through interbreeding, the variants
came over to the ancestors of modern humans about 60,000 years ago.

"It is striking that the genetic heritage from Neanderthals has such
tragic consequences during the current pandemic," said Professor Svante Pa"a"bo, who leads the Human Evolutionary Genomics Unit at the Okinawa Institute of Science and Technology Graduate University (OIST).

Is severe COVID-19 written in our genes? Chromosomes are tiny structures
that are found in the nucleus of cells and carry an organism's genetic material. They come in pairs with one chromosome in each pair inherited
from each parent. Humans have 23 of these pairs. Thus, 46 chromosomes
carry the entirety of our DNA -- millions upon millions of base pairs. And although the vast majority are the same between people, mutations do
occur, and variations persist, at the DNA level.



==========================================================================
The research by the COVID-19 Host Genetics Initiative looked at
over 3,000 people including both people who were hospitalized with
severe COVID-19 and people who were infected by the virus but weren't hospitalized. It identified a region on chromosome 3 that influences
whether a person infected with the virus will become severely ill and
needs to be hospitalized.

The identified genetic region is very long, spanning 49.4 thousand base
pairs, and the variants that impose a higher risk to severe COVID-19 are strongly linked -- if a person has one of the variants then they're very
likely to have all thirteen of them. Variants like these have previously
been found to come from Neanderthals or Denisovans so Professor Pa"a"bo,
in collaboration with Professor Hugo Zeberg, first author of the paper and
a researcher at the Max Planck Institute for Evolutionary Anthropology and Karolinska Institutet, decided to investigate whether this was the case.

They found that a Neanderthal from southern Europe carried an almost
identical genetic region whereas two Neanderthals from southern Siberia
and a Denisovan did not.

Next, they questioned whether the variants had come over from Neanderthals
or had been inherited by both Neanderthals and present-day people through
a common ancestor.

If the variants had come from interbreeding between the two groups
of people, then this would have occurred as recently as 50,000 years
ago. Whereas, if the variants had come from the last common ancestor,
they would have been around in modern humans for about 550,000 years. But random genetic mutations, and recombination between chromosomes, would
have also occurred during this time and because the variants between the Neanderthal from southern Europe and present-day people are so similar
over such a long stretch of DNA, the researchers showed that it was much
more likely that they came from interbreeding.



========================================================================== Professor Pa"a"bo and Professor Zeberg concluded that Neanderthals
related to the one from southern Europe contributed this DNA region to present-day people around 60,000 years ago when the two groups met.

Neanderthal variants pose up to three times the risk Professor Zeberg
explained that those who carry these Neanderthal variants have up to
three times the risk of requiring mechanical ventilation. "Obviously,
factors such as your age and other diseases you may have also affect
how severely you are affected by the virus. But among genetic factors,
this is the strongest one." The researchers also found that there are
major differences in how common these variants are in different parts of
the world. In South Asia about 50% of the population carry them. However,
in East Asia they're almost absent.

It is not yet known why the Neanderthal gene region is associated with increased risk of becoming severely ill. "This is something that we and
others are now investigating as quickly as possible," said Professor
Pa"a"bo.


========================================================================== Story Source: Materials provided by Okinawa_Institute_of_Science_and_Technology_(OIST)
Graduate_University. Original written by Lucy Dickie. Note: Content may
be edited for style and length.


========================================================================== Journal Reference:
1. Hugo Zeberg, Svante Pa"a"bo. The major genetic risk factor for
severe
COVID-19 is inherited from Neanderthals. Nature, 2020; DOI:
10.1038/ s41586-020-2818-3 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200930094758.htm

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