The plague epidemic which struck Europe around 1350 led to the selection of a gene that protected us from this bacterial disease, but which today increases the risk of autoimmune pathologies, shows a Study published in “Nature”.
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An epidemic scourge can shape the genes that control the battalions of our immune cells. a study published on October 19 in the journal Nature In offer a brilliant demonstration. The black plague: even today, this name is synonymous with a fatal event. In the 14th e century, this large mower has spread like a trail of powder across Europe, propagated by the rat. Rodents, whose chips hosted the plague bacteria, Yersinia Pestis, were brought back from Asia by commercial ships.
This disease sometimes caused painful and pestilential bubbles in terms of groin or armpits, sometimes lightning respiratory symptoms, the forms it was taking up in the same patient. Terribly contagious, it decimated in a few years, from 1348 to 1352, between 25 and 45 million people across Europe. In doing so, she also selected certain genes: those who protected the lucky ones who, by the grace of the genetic lottery, had been equipped with it.
“We are the heirs of this selection phenomenon, notes Javier Pizarro-Cerda, co-author of this work, responsible for a research unit on Y. Pestis at the Institut Pasteur, in Paris. The version of the gene that wears us best against the plague is present in half of the French, for example. “
From the DNA of dental pulp
The researchers compared the DNA of survivors of the black plague and their descendants to that of its victims or deceased people before the passage of the scourge. For this, they analyzed the genome of 206 skeletons buried before, during or after this epidemic, in three burial places in London and five in Denmark. The dates of burials were known there thanks to dating in radiocarbon, stratigraphy or historical archives. “The strength of this study was to target a very precise period, relating to a well -dated event – the plague. And therefore to attribute to this pandemic a phenomenon of selection of genes”, explains Christian remains, of the Institute Pastor, study co -author.
Among these human remains, 42 came from a common pit dug in London in 1348 and 1349: the two years, precisely, where the epidemic struck the British capital. Anticipating the impact of the wave, the city had also rented land to install cemeteries in an emergency … The researchers also analyzed the remains of 67 people who disappeared before the pandemic – between 1000 and 1250 in London, between 850 and 1350 in Denmark. And those of 107 individuals who died after 1350 and 1539 in London, between 1350 and 1800 in Denmark.
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