The ancient skeleton of a woman who lived near the storied city of Troy has given up the secrets of what killed her. Researchers unearthed the Byzantine bones and discovered both that she was pregnant and that a bacterial infection probably caused her death.
In the 800-year-old bones, which had been buried in a grave lined with stones, researchers discovered strawberry-sized nodules near her ribs. After opening the nodules, the researchers found “ghost cells,” and were even able to fully extract and piece together the DNA of the bacterial strains that killed her when she was likely around 30 years old, during the era of the Byzantine Empire.
“Amazingly, these samples yielded enough DNA to fully reconstruct the genomes of two species of bacteria, Staphylococcus saprophyticus and Gardnerella vaginalis, which infected the woman and likely led to her death,” Hendrik Poinar, of McMaster University's Ancient DNA Centre, said in a statement.
The ancient DNA the researchers were able to extract and study came not only from the bacteria, but the woman herself, as well as evidence of what they think was a male fetus.
“Calcification made little tiny suitcases of DNA and transported it across an 800-year timespan,” Caitlin Pepperell, an assistant professor at University of Wisconsin–Madison, said in the statement.
Interestingly, the researchers think that one of the ancient strains of bacteria, Staphylococcus saprophyticus, occupied a different niche in the past, and jumped between livestock and humans at a time when it was common for people to cohabitate with animals.
“The strain from Troy belongs to a lineage that is not commonly associated with human disease in the modern world,” Pepperell said. “We speculate that human infections in the ancient world were acquired from a pool of bacteria that moved readily between humans, livestock and the environment.”
The researchers believe that the woman led a difficult agrarian life, and that the bacterial infection that killed her was related to her pregnancy. Their investigation of the ancient bones was published in the journal eLIFE.
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