HELP What Did Scientists Study?
Scientists in one study believed the modern plague and the plague of the 1300s are both
caused by the same bacterium: Yersinia pestis (Y. pestis). They suspected, though, that there
are variants of Y. pestis. There is probably one that caused the very serious plague years
ago and one that causes the less serious plague today.
In the study, the researchers looked at the DNA of Y. pestis from the 1300s and the DNA of Y.
pestis from today. They hoped to discover any differences. Some people carrying Y. pestis
died nearly 800 years ago. Still, researchers could get some DNA from their bones and teeth.
They were able to test the bones and teeth of 100 people who died from the disease in the
1300s.
The researchers did not find any different kinds of Y. pestis. They were disappointed. They
had hoped to find out why the Black Death was so serious.
Researchers plan to continue to look at the DNA of Y. pestis. Understanding ancient
pathogens is important, they say. Doctors might be able to predict the next deadly plague. If
so, they may be more ready to deal with it.