According to research, the Black Death shaped our genes and our immune system.

The Black Death – the most devastating event in history – not only wiped out half of Europe’s population in less than five years, it also changed our genome and immune system.

According to a study published this Wednesday in the journal Nature, the same genes that once protected us from Black Deathtoday they are associated with a greater susceptibility to autoimmune pathologies such as Crohn’s disease and rheumatoid arthritis.

The authors of a study conducted by the University of Chicago (USA), McMaster University (Canada) and the Pasteur Institute (France) studied the genetic impact of bubonic plague, which wiped out 30% to 60% of the population of North Africa, Europe and Asia 700 years ago.

It has long been assumed that the pandemic Black Deathbacterial Yersinia plaguecould exert selective pressure on humans, but this has been difficult to prove from modern populations because humans have faced many selective pressures since then.

Ancient DNA samples sequenced

For this study, the team sequenced ancient bone DNA samples from more than 200 people in London and Denmark who died before, during and after the passage of the hurricane. Black Deathlate 1340

from 300 genes in terms of immunity, four were selected that, depending on the variant, protected or increased susceptibility to Y. pestis.

The team focused on gene with a particularly strong association with susceptibility: ERAP2, which helps the immune system recognize the presence of an infection.

People who had two copies of a particular genetic variant, designated rs2549794, were able to make full-length copies of the ERAP2 transcript and produce more functional protein.

“When a macrophage encounters a bacterium, it cuts it apart to signal to other immune cells that there is an infection. geneprobably improves our immune system’s ability to detect an invading pathogen,” explains Luis Barreiro of the University of Chicago and co-author of the study.

“We estimate that having two copies of the rs2549794 variant would increase a person’s chance of survival by 40%. Black Death than those who had two copies of the non-functional variant,” he says.

Then in the lab, the team showed that the rs2549794 variant affects the ability of living human cells to fight plague, and that macrophages expressing two copies of this variant are more effective at neutralizing Y. pestis than macrophages. have it.

“These results support ancient DNA evidence that rs2549794 protects against Black Death”, according to Javier Pizarro-Cerda of the Pasteur Institute.

Susceptibility to current diseases

But over time, our immune systems have evolved to respond to pathogens, and what was once a protective gene against plague is now associated with increased susceptibility to autoimmune diseases. The authors point out that this is a balancing act with which evolution plays with our genome.

This study is the first approach to how pandemics can change our genomes and go unnoticed by modern populations.

Future research will expand the project to study the entire genome, not just a set genes associated with immunity.

“Understanding the dynamics that have shaped the human immune system is key to understanding how past pandemics, such as plague, contribute to our disease susceptibility today,” said co-author Hendrik Poinar of McMaster University.

(As reported by EFE)

“Espacio Vital”: Pamela Blas, a nutritionist, gives us advice on how to use the nutritional value of various products from our country’s regions. And he recommends that half of the plate be vegetables, the remaining half divided by 2 and the first quarter should include protein, like chicken, and the other quarter of the plate should be carbohydrates, like flour or rice.

Fernando Carvallo selects information and shares his vision of national and international news. sign to our newsletter Things As They Are to read their daily columns.