DNA studies used to identify ancient cargo

For the first time, researchers have identified DNA from inside ceramic containers in an ancient shipwreck on the seafloor, making it possible to determine what the ship's cargo was even though there was no visible trace of it.For the first time, researchers have identified DNA from inside ceramic containers in an ancient shipwreck on the seafloor, making it possible to determine what the ship's cargo was even though there was no visible trace of it.

By scraping samples from inside two of the containers, called amphoras, the researchers were able to obtain DNA sequences that identified the contents of one as olive oil and oregano. The other probably contained wine, and the researchers are conducting further analyses to confirm this.

Many archeologists specialize in the study of amphoras, which were the cargo containers of the ancient world, used for shipping all kinds of liquid or semi-liquid goods. But the study of these containers can be frustrating, Foley said, because after centuries on the seafloor, the contents have usually been washed away and archeologists are "just left with empty bottles."

The new research points the way toward analyzing hundreds of containers, which could "tell us what was being traded, and something about the total agricultural production of a country," Foley said. Such analysis of ancient crops could even yield insights into the climate of that period.

The discovery of DNA from olive oil and oregano in one amphora came as a surprise, Foley says, because Chios was well-known in the ancient world as a major exporter of highly prized wines, and archeologists had assumed that amphoras from a ship in that area would have been carrying wine.

The other amphora from which Foley and Hansson were able to extract DNA may indeed have contained wine, although that is not yet certain. The short fragments of DNA they found may have come from pistachios or from resins used to coat the insides of amphoras that carried wine. Analysis continues, using present-day samples of plants from the island to pin down the identification.