This Genetic ‘Trick’ Helped the Black Death Linger for Centuries

Yersinia pestis—the bacterium that causes the bubonic plague—experienced a genetic tweak that allowed rodents to live longer after they were infected, according to a new study. This alteration may have prolonged two significant plague pandemics, including the deadliest event in human history: the Black Death. Researchers at the Institut Pasteur in France and McMaster University in Canada studied hundreds of ancient Y. pestis DNA samples to investigate a gene called “pla.” Their study, published May 29 in the journal Science, identified a decrease in repetitions of the pla gene in the Y. pestis genome during the later stages of both the first and second major plague pandemics. The researchers believe these pla depletions ultimately allowed these pandemics to last longer. The first plague pandemic, known as the Plague of Justinian, struck the Mediterranean basin during the sixth century and caused tens of millions of deaths over the course of two centuries. The second emerged when the ... Read full article.