The Justinianic Plague killed 50 million people from the sixth to eighth centuries, and was caused by the same species of bacteria, Yersinia pestis, as the Black Death, which struck Europe during the Middle Ages.
The new genetic analysis reveals that three of the genes of this bacteria likely contributed more to the spread of the plague than previously thought. In addition, the researchers found mutations that were unique to the strain of Yersinia pestis that caused the Justinianic Plague.
The new study also confirms some findings from an earlier study, published in 2014, that involved a genetic analysis of a different human skeleton that dated to about the same time as the skeleton in the new study, the start of the sixth century.
“We now have a complete Justinianic re-constructed genome, as opposed to the partial draft genome that was published in 2014,” Michal Feldman, the lead author of the new study and a researcher at the Max Planck Institutes in Germany, told Live Science in an email.
That earlier study was led by David Wagner, an ecologist at Northern Arizona University. The new findings are “a validation of what we found previously with a different sample, which is exciting,” Wagner told Live Science.
In the new study, the researchers looked at plague DNA found in a skeleton buried in Altenerding, near Munich, just 12 miles (20 kilometers) from the site where the skeleton analyzed in the 2014 study was buried.