The Black Death, or bubonic plague, wiped out as much as 50% of populations in Europe, northern Africa and the Middle East..
Our ancestors who survived the Black Death carried a gene that makes us more susceptible to certain diseases, a new study has found.
The finding goes a long way toward explaining the way germs shape our genetic makeup throughout history, according to research published last week in the journal Nature.
"Our genome today is a reflection of our whole evolutionary history," said Luis Barreiro, a senior author of the study. How human genes protected survivors of the bubonic plague has greatly impacted our immune systems.
That impact increases our risk for autoimmune disorders such as lupus and Crohn's disease, the research found.
The Black Death, which was an outbreak of bubonic plague in the 14th century, is the single deadliest event in recorded history. It spread throughout Europe, northern Africa and the Middle East, killing up to 30% to 50% of those populations.
That mortality rate is at least 200 times higher than COVID's death rate.
Barreiro and colleagues at the University of Chicago, Ontario's McMaster University, and the Pasteur Institute in Paris analyzed genetic samples from the skeletons of more than 200 people who died in London and Denmark over a 100-year period as the plague swept through their regions.
Researchers found that survivors of the Black Death had a gene mutation that helped protect them from the plague pathogen, Yersinia pestis, which is carried by rodent fleas. Survivors passed those mutations on and many Europeans still carry them.
Barreiro said he doesn't think the COVID-19 pandemic will substantially affect future evolution because the death rate is drastically lower than the Black Death's and because most of those who died from COVID-19 had already had children.
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