When the Black Death rampaged through Europe in the mid-1300s, no one — rich or poor, old or young — was safe.
It was the deadliest pandemic in human history, and by the end of the bubonic plague's terrifying march, between 30 and 60 percent of Europe's population had perished. The Black Death ended nearly 700 years ago, but a groundbreaking new study in the journal Nature shows that the impacts are still apparent in our genes and health today.
Researchers analyzed DNA from 206 ancient skeletons buried before, during, and after the Black Death, according to the BBC. Some bones were exhumed from Black Death-era mass burial pits in London, while other samples came from Denmark. And what they found was stunning: Individuals with specific mutations in a gene called ERAP2 were 40 percent more likely to survive the plague. The researchers say it's the strongest natural selection event to ever occur in humans, leaving an indelible footprint on the human genome.
But while that added immune response served a purpose during the Black Death, today those mutations are instead associated with susceptibility to auto-immune disorders such as Crohn's disease, when the body attacks itself. In other words, this once-helpful mutation may make our immune systems too good at their jobs.
According to Nature, the study is the first to prove a link between ancient pandemics, their influence on the human genome, and how present-day humans respond to disease.
