Using DNA to answer questions regarding historical archaeology

Hunting for a Mass Killer in Medieval Graveyards

The agent of the Black Death is assumed to be Yersinia pestis, the microbe that causes bubonic plague today. But the epidemiology was strikingly different from that of modern outbreaks. Modern plague is carried by fleas and spreads no faster than the rats that carry them can travel. The Black Death seems to have spread directly from one person to another.

Victims sometimes emitted a deathly stench, which is not true of plague victims today. And the Black Death felled at least 30 percent of those it inflicted, whereas a modern plague in India that struck Bombay in 1904, before the advent of antibiotics, killed only 3 percent of its victims.

These differences, as well as the fear that the Black Death might re-emerge, have prompted several attempts to retrieve DNA from Black Death cemeteries. The latest of these attempts is reported Tuesday in of The Proceedings of the National Academy of Sciences by a team led by Hendrik N. Poinar of McMaster University in Ontario and Johannes Krause of the University of Tübingen in Germany.

The scientists are looking for what aspects of the mediaeval strain of Yersinia pestis, confirmed to be the culprit, made it so deadly. Of course, in the first waves, there the lack of exposure, the lack of immunity. Plague has been implicated on the European continent in Roman times, but not later, until the 14th century outbreak, to my knowledge. Other news reports on this story ran headlines like, 'Bug that caused the Black Death extinct!', which is technically true--it is believed that that particular strain is, but of course Yersinia pestis and plague do persist, including in the American West, and by studying how the bacterium might have changed over history, then we might get a better understanding of how it, along with other bacteria, could evolve into more virulent strains. I'm interested in what further research will find.