Neanderthals’ genetic inheritance, a factor that could be crucial against COVID-19

New studies seem to have discovered the Links between how COVID-19 manifests and the presence of inherited Neanderthal genetics.

To the extent that nearly half of the Neanderthal genome still survives, scattered in small amounts among almost all the DNA of the current population – with the exception of Africans, as it seems Neanderthals never lived on the continent – these genes have been associated with everything from body hair to fat metabolism.

Many appear to be related to the immune system and to be decisive before the risk of developing diseases such as lupus, Crohn’s disease, diabetes and, according to scientists, Covid-19 also belongs to this list. Two long sections of DNA, both inherited from Neanderthals, appear to confer resistance or susceptibility to severe COVID-19, depending on who is present.

The surveys were carried out by scientists Svante Pääbo and Hugo Zeberg in the German city of Leipzig, both pioneers in the study of Neanderthal DNA.

His first article, published in Nature in September, he described a chain of Neanderthal DNA, known as a “haplotype”, associated with an increased risk of serious illness. Having a copy of the haplotype, which is found on the third of 46 chromosomes humans have, doubles the chance of ending up in intensive care. Those who are unlucky enough to own two copies, one from each parent, are at even greater risk.

But this Genetic bad luck is not evenly distributed. The genetic sequence is most common in people of South Asian descent, with 63% of the Bangladeshi population carrying at least one copy; and among Europeans, where the prevalence is around 16%. As expected, it is virtually absent from Africa. Surprisingly, it is also very rare in large parts of East Asia, explains an article by The Economist.

The second study, published this week in Proceedings of the National Academy of Sciences, refers to another Neanderthal haplotype, found on chromosome 12. Its effect is protective, although it is also less powerful: having a single copy is associated with a 22% lower risk of serious illness.

This useful sequence is more common than the harmful sequence. It is present in all regions of the world except sub-Saharan Africa. Between 25% and 35% of the Eurasian population wear at least one copy. In Vietnam and eastern China, more than half of the population is carriers. It also exists, at much lower rates, among American populations of predominantly African descent, many of whom will also have more recent Eurasian ancestry.

The haplotype prevents the spread of RNA viruses, including sars-cov-2, by causing the infected cells quickly self-destruct. It is known to provide at least some protection against West Nile virus, hepatitis C and, interestingly, sars-cov-1, which caused the outbreak of sars that began in 2002.

“There are certainly other factors, such as advanced age or underlying conditions such as diabetes that have a major impact on the development of the disease,” said Professor Pääbo of the Genomics Unit evolution of OIST. “But genetic factors also play an important role and some of them were contributed by Neanderthals.”

The researchers hope their work will help clarify why some countries, and populations in those countries, appear to have been more affected by COVID-19 than others. They point out, for example, that Britons of Bangladeshi descent are suffering from severe COVID-19 at about twice the rate of the general population.

If COVID-19 becomes an endemic disease, as seems likely, gene sequencing could, in the future, help clinicians assess patients who may be vulnerable to its worst effects. Understanding the mechanisms by which genes confer resistance or susceptibility can help in drug research. And history suggests that sars-cov-2 is unlikely to be the last new coronavirus to jump from animals to humans.

According to scientists, Neanderthals became extinct around 40,000 years ago, although they did not completely disappear from Earth. Over the past decade, it has become clear that Neanderthals mated with the ancestors of modern humans, and at least some of these unions produced viable offspring. The result is that almost half of the Neanderthal genome still survives, scattered in small amounts throughout most of the DNA of modern people.

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