Ancient sediments and dental calculus reveal hidden human histories
Thursday 3rd September 2026 on 09:45 in
Estonia
Ancient DNA, proteins and other molecules preserved in soil sediments around bones and in dental calculus can reveal details of people’s lives and diseases that are not visible in skeletal remains, ERR reports, citing a doctoral thesis defended at the University of Tartu.
“The strength of ancient biomolecules is that they allow us to look beyond what is visible on bones,” said Biancamaria Bonucci, a junior researcher in ancient DNA at the University of Tartu.
Many diseases leave no traces in bones and can only be identified through ancient DNA and proteins. Written historical sources are also often incomplete, meaning that the spread of a disease in a particular region may only become clear through biomolecular research.
In her doctoral thesis, Bonucci studied ancient proteins and DNA from different materials, focusing in particular on sediments accumulated around bones and on dental calculus. The materials can provide information about skeletons, individuals and burial environments, including which domestic animals people kept, which species they encountered, what diseases they suffered from and what the local climate was like during their lives.
One study found DNA from a lineage of domestic rats, Rattus rattus, that is now extinct in England. Proteins characteristic of the same rat were also found in the sediment, confirming the species identified through the DNA.
In another study, Bonucci examined dental remains from residents of Sint Truiden, a medieval and early modern city in what is now Belgium. The samples indicated that the city’s population had been exposed to the virus that causes hepatitis B and to Borrelia recurrentis, a fever-causing bacterium spread by lice.
The research also found traces of the plague bacterium Yersinia pestis dating from the 14th century, although the finding was not recorded in any chronicles. While plague victims were usually buried in mass graves, the people in Sint Truiden who carried signs of plague had been buried in individual graves. They may have been infected but died so quickly that the exact circumstances remain unknown.