While most individuals tend to think of the Bubonic Plague when they revisit humanity’s great plagues (a favorite pastime of any well-natured person), the first infamous plague to wreak havoc upon human civilization was the Justinian Plague in the sixth century. This horrendous plague killed over 25 million people in its 200-year reign of terror throughout the Byzantine Empire and throughout the Mediterranean.
Having looked back on this apocalyptic plague, a team of German researchers thought it’d be a great idea to recreate this plague using a genome reconstructed from known plague victims. Yep, sounds about right.
According to the scientists' recent study published in Molecular Biology and Evolution, the reconstructed plague genome revealed new genetic information about Yersinia pestis, the bacterial culprit:
Here we present a new high-coverage (17.9 fold) Y. pestis genome obtained from a 6th-century skeleton recovered from a southern German burial site close to Munich. The reconstructed genome enabled the detection of 30 unique substitutions as well as structural differences that have not been previously described.
The genome was able to be reconstructed thanks to the remains of a plague victim disinterred from the Altenerding, an ancient German burial site near Munich. Study co-author Michaela Harbeck told Phys.org that preserving skeletons like the ones used in this study is of utmost importance for genetic archaeologists:
We were very fortunate to find another plague victim with very good DNA preservation in a graveyard just a few kilometers from where the individual analyzed in [a previous study] was found. It provided us with the great opportunity to reconstruct the first high quality genome in addition to the previously published draft genome.
The newly reconstructed genome shows a host of previously undetected mutations that led to many victims being wrongly diagnosed. This new information shows that the plague was much farther reaching than was previously estimated, and might allow researchers to reconstruct the evolution and spread of the deadly plague.
It is still unknown why the bacteria which caused the Justinian Plague suddenly died out some time in the eighth century. This research might lead to new discoveries about the genetic history of the bacteria, giving a glimpse into the factors that could have saved humanity from this terrible plague.