Published:
2025-02-12 12:52:00
A reconstruction of the Imperial harbour at Portas, Rome, by Renato Saleri © R. Fabro – R. Saleri
Port harbours are the umbilical cords of civilizations. They unite land and sea and offer a unique window into population, diet, health, technology, and environmental change. But are they also DNA traps?
A team, part-funded by the
Leverhulme Trust
and supported by the
Southampton Marine and Maritime Institute
(SMMI), is working to find out.
The Ancient Ports of Europe: A Novel Genetic Window on Ancient Lives
(PortGEN) project, aims to investigate whether ancient DNA is preserved in the sediments of historic European and Mediterranean harbours. Because many of these harbours silted up and were abandoned, they hold a rich sedimentary record. Until now, researchers have studied these records using plant and animal remains, microfossils like pollen and diatoms, and geochemistry. However, recent studies suggest that shallow-marine and tidal sediments can retain ancient sedimentary DNA (sedaDNA) for thousands of years. PortGEN will be the first project to systematically explore this potential, using sediments, much already collected, from some of the ancient world’s most renowned ports, including Rome (Ostia, Portus), Venice, and Ephesus. Through this research, the team hopes to gain fresh insights into the lives and economic activities of ancient civilizations.
Being the lifeblood of complex societies, ports can reveal how past communities adapted to environmental changes, from disease outbreaks to flooding. Until now, the history of ports has been explored through archaeology, historical texts, plant and animal remains, microfossils, and geochemistry. The discovery 20 years ago that ancient extracellular DNA can be preserved in sediments has since led to its use in studying lakes, estuaries, floodplains, soils, and marine environments. Recent research beyond archaeology has demonstrated that shallow-marine sediments can retain sedaDNA for thousands of years. This suggests that the sedimentary traps of ancient harbours, particularly in warmer climates, may provide a well-preserved genetic archive. SedaDNA forms when plant and animal tissues break down, with tiny DNA fragments attaching to sediment particles, where they are protected from microbial decay.
Recent studies on the sedimentology and geomorphology of ancient ports have improved our understanding of siltation processes and dredging impacts, both essential for to deriving reliable time-sequences spanning well-defined periods in Classical antiquity. These advances, coupled with new sedimentological techniques—such as portable optically stimulated luminescence—will be tested at two smaller port sites in southern England and one in southern France. SedaDNA analysis will primarily be done through metabarcoding, a process that involves extracting DNA and amplifying targeted regions of ancient DNA sequences from the sediment through polymerase chain reactions (PCR). Additionally, the project will employ non-PCR techniques to assess DNA quality and detect various microbiological remains, including pathogens and gut bacteria from humans and animals.
The PortGEN team includes
Professor Tony Brown
,
Dr Ben Pears
, Dr Ferréol Salomon, Jean-Philippe Goiran & Kevin Walsh, in collaboration with the CNRS (Strasbourg, France), SMMI (UK), Mediterranean world experts, and site excavators.
Left:
The changing cityscape of the Imperial coast and harbour at Portus. © R. Fabro – R. Saleri 2018;
Right:
Coring rig in extracting sediment in the old channels and harbour of Ostia courtesy of Ferréol Saloman.