Scientists at the Mario Negri Institute have discovered that carriers of certain Neanderthal genes are more exposed to the risk of developing severe Covid. Why we still have the genes of our “cousin ancestors” today and how they can influence susceptibility to certain diseases.
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The risk of contracting severe form from the COVID-19the illness caused by coronavirus SARS-CoV-2is linked to a multitude of factors, including theageil type (men are more exposed), the underlying diseases and much more. Several studies have highlighted that even the genetic heritage can affect your chances of getting seriously ill, such as a research conducted by the University of Sienawhich found an association between severe Covid with some variants of thedrying (WES)1. A new study coordinated by researchers from the Mario Negri IRCCS Pharmacological Research Institute, in collaboration with colleagues from the Aldo and Cele Daccò Research Center for Rare Diseases, the Anna Maria Astori Center and the Science and Technology Park Kilometro Rosso, has determined that people are also at risk carriers of some specific genes inherited from Neanderthal man.
The researchers coordinated by professor Giuseppe RemuzziDirector of the Mario Negri Institute, reached their conclusions after carrying out the genetic sequencing of approximately 1,200 people residing in the province of Bergamo (Val Seriana), the one hardest hit at the beginning of the pandemic in our country. Starting from a sample of around 10,000 participants, the researchers managed to analyze three groups of people divided with the following characteristics: 400 affected by severe COVID-19; 400 with mild form and 400 not infected by SARS-CoV-2. Through a technique of genotyping call DNA microarray“a technology capable of reading hundreds of thousands of variations (polymorphisms) across the entire genome”, as indicated in a press release from the Milanese institutediscovered that carriers of a particular combination of genetic variations (aplotype) was more susceptible to developing the severe form of the disease, as well as having more dead in the family due to the pandemic pathogen.
The genes involved are found on the chromosome 3there are three and we have all inherited them from our cousin ancestors, the Neanderthals (Homo neanderthalensis). More specifically, they are vestiges of the “di Vindi genome” found in Neanderthals who lived 50,000 years ago. It’s about CCR9 e CXCR6“responsible for attracting white blood cells and causing inflammation during infections,” and the gene LZTFL1, linked to epithelial cells located in the respiratory tract. As explained by Dr. Marina Noris, Head of the Human Genomics Center of the Mario Negri Institute, carriers of the “Neanderthal haplotype” exposed to the SARS-CoV-2 coronavirus had “more than double the risk of developing severe Covid (pneumonia) , almost three times the risk of needing intensive care and an even greater risk of needing mechanical ventilation compared to subjects who do not have this haplotype.” Italian researchers have also identified other portions of the genome potentially associated with the risk of contracting the infection and becoming seriously ill, which will be subject to further in-depth studies.
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But let’s focus on the genes of Neanderthal man, regularly present in our genetic heritage and capable of influencing the risk of developing or not developing certain pathologies. The fact that we have them in our DNA comes from a simple reason: modern humans (A wise man) in the past mated with Neanderthals, making their genes arrive – generation after generation – up to the present day. It is estimated that the first meetings took place around 200 thousand years ago, when the first modern humans left Africa and reached Asia and Europe. Here they met Neanderthals, with whom they most likely entered into significant contact competition, net of the genetic exchanges mentioned above. Anthropologists believe that it was precisely this competition, in association with environmental and demographic factors, that led to the extinction of our cousins around 40,000 years ago.
It is believed that the cross between the two species of hominids has brought us up to the present day 20-30 percent of the genetic heritage of Neanderthals, diluted in the various populations on the basis of geographical origin. On average, each modern human would carry 1 to 3 percent of these ancient Neanderthal genes. And they are not inert geniuses. Their presence, in fact, is linked to the susceptibility or otherwise to various pathologies, including the morbo in Chronil type 2 diabetes e autoimmune diseases like Lupus. The reason is linked to the fact that we have evolved in different environments that have evolutionarily shaped distinctive traits, such as cold resistance or perhaps a greater reactivity of the immune system, which today can represent advantages or disadvantages. In the case of COVID-19, the genes involved most likely protected Neanderthals from infections, as explained by Professor Giuseppe Remuzzi; today, however, they can cause an excessive immune response. The reference is to the infamous “cytokine storm”, a condition that can be more serious than the infection itself. Many Covid patients have lost their lives due to an exaggerated immune reaction. The details of the research “A GWAS in the pandemic epicenter highlights the severe COVID-19 risk locus introgressed by Neanderthals” were published in the scientific journal iScience.