According to a study, the descendants of survivors of the Black Death are more exposed to autoimmune diseases.
- The Black Death plagued Europe, West Asia and North Africa in the mid-14th century.
- This infectious disease has killed up to 50% of the European population according to the CNRS.
Will the current coronavirus pandemic affect the genes and therefore the health of future generations? This is a legitimate question to ask in view of the fascinating results of a study published in Nature.
Indeed, according to French and American researchers, people carrying certain protective genes against the Black Death in the MiddleAge also passed these genes on to their descendants, protecting them in turn.
But this genetic inheritance has made them more susceptible to developing other diseases that affect the immune system, such as Crohn’s disease and rheumatoid arthritis.
Thus, it appears that what makes it possible to survive at one time can alter survival and cause other illnesses at another time.
The Black Death shaped the evolution of immune genes
To conduct their research, University of Chicago scientist Jennifer Klunk, in association with researchers from McMaster University (Canada) and the Institut Pasteur, analyzed more than 200 DNA samples.
Some were extracted from the remains of individuals who died before, during or after the Black Death in London and other samples were taken from human remains in five localities in Denmark. Of the four genes associated with survival from the Black Death, one has particularly caught the attention of scientists. Indeed, people with the ERAP2 gene were less affected by the plague and had a 40-50% higher survival rate compared to those with different gene variants.
The survivors therefore passed this gene on to their children, developing better resistance to this disease in the population, which is a fine testimony to human genetic adaptation: “Near-decadal plague epidemics in the four hundred years after the second pandemic in Europe were often (but not always) associated with reduced death rates“, say the authors.
Crohn’s disease: ERAP2 gene increases risk
But this gene is also “associated with increased susceptibility to autoimmune diseases“, according to the study. Having the ERAP2 gene is indeed a risk factor for Crohn’s disease, chronic inflammatory bowel disease that affects nearly one person in 1,000 in France.
The authors of the study believe that their work proves “the role played by past pandemics in determining current vulnerability to disease“.
