The genetic code inherited from Neanderthals increases the risk of serious Covid, but protects it from HIV.

New Delhi: The genetic code inherited from the Neanderthals (found to be associated with an increased risk of severe Covid’s disease) provides insights into human DNA fragments that have captivated two scientists, according to a new study. , Protecting humans from HIV Years.

The Neanderthals are an extinct species of ancient people that lived in Eurasia until about 40,000 years ago.

Hugo Zeberg and Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Germany have been studying part of the genetic code since 2020. They found that some of the genetic code on chromosome 3 was susceptible to severe Covid. Neanderthals over 50,000 years ago.

Chromosomes are thread-like structures inside the nucleus of a cell. Each chromosome is made up of a single molecule of protein and deoxyribonucleic acid (DNA). DNA contains specific instructions or genetic codes that make each individual unique.

Humans have 23 pairs of chromosomes. People usually have two copies of each chromosome.

and study Was announced in New England Journal of Medicine In October 2020, researchers discovered a strong link between severe Covid-19 and the two genomic regions. One region on chromosome 3 containing 6 genes and one region on chromosome 9 that determines the ABO blood group.

Chromosome 3 spans nearly 200 million base pairs or “letters” and represents about 6.5 percent of the total DNA in the cell. Researchers have found that a unique combination of approximately 50,000 base pairs of chromosome 3 puts people at risk for severe Covid-19.

The gene in question is carried by 30% of the South Asian population, but is almost completely absent in Africans.

The Max Planck Institute for Evolutionary Anthropology duo has a string of DNA that increases people’s risk of severe Covid-19. Neanderthal People who lived in Croatia over 50,000 years ago.

The team later also discovered that the frequency of DNA has increased significantly since the Last Glacial Period. In fact, genetic variation inherited from Neanderthals has become unexpectedly common.

What has puzzled scientists is that genes that make humans more susceptible to disease must not withstand thousands of years of evolution. The only rational explanation for that is that this fragment of DNA coding had a positive effect that scientists didn’t know about.

“This major genetic risk factor for COVID-19 is so common that we began to wonder if it could actually help something, such as providing protection against another infection,” Zeberg said. Stated in a statement.

Genetic risk factors are located in the region on chromosome 3, which consists of many genes. Nearby are several genes that encode receptors for the immune system.

One of these receptors, CCR5, is used by the HIV virus to infect white blood cells.

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New question

In the latest research, Release Tuesday PNAS, Zeberg found that people with Covid-19 risk factors have fewer CCR5 receptors. This led him to test for a low risk of becoming infected with HIV.

By analyzing patient data from three major biobanks, he found that carriers of the Covid-19 risk variant had a 27% lower risk of becoming infected with HIV.

“This shows how genetic variation can be both good and bad news. Bad news if a person gets infected with COVID-19, good to prevent getting infected with HIV. It’s news, “says Zeberg.

However, the findings raise new questions. Since HIV occurred only in the 20th century, protection against this infection alone cannot explain why mutations in the genetic risk of Covid-19 became so common among humans 10,000 years ago. ..

“We now know that this risk variant of COVID-19 provides protection against HIV, but it was probably protection against yet another disease that increased its frequency since the Last Glacial Period.” Zeberg said.

According to some scientists, modern humans migrated from Africa and mated with Eurasian Neanderthals about 200,000 years ago. 140,000 years later, Eurasians with Neanderthal ancestry migrated to Africa and mated with human descendants who had never left.

As a result, about 1-4% of the Eurasian, Native American, and North African genomes come from Neanderthals. About 20% of the Neanderthals genes still survive in humans today.

Bangladesh has the highest frequency of this gene, with more than half of the population (63%) having at least one copy of the Neanderthal risk variant and 13% having a similar variant of the gene segment.

About 8% of Europeans have this subspecies, but for mixed-race Americans, this subspecies is present in 4% of the population.

(Edited by Nida Fatima Siddiqui)

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