DNA traces reveal that cocoa was consumed in what is now the state of Georgia, United States, nearly 1,000 years ago.
The discovery comes from the Etowah site, an ancient Indigenous town in the southeastern United States. Archaeologists had found fragments of pottery there dating from the 11th and 12th centuries. Two of these fragments contain tiny DNA sequences belonging to the cacao tree, Theobroma cacao.
Open cacao pods showing the beans inside.
Credit: Wikimedia Commons — CC BY-SA 4.0.
Wikimedia image
The result is surprising for one simple reason: the cacao tree is a tropical plant that does not grow naturally in Georgia. The cocoa found at Etowah, or a product made from it, must therefore have traveled a long distance before reaching the site. The exact route remains unknown.
This discovery also resolves a long-standing uncertainty. An earlier analysis of 31 pottery fragments from Etowah had detected several substances found in cocoa. But these same molecules also occur in yaupon holly, a local plant used to prepare a caffeinated drink. Chemical analyses alone therefore could not settle the question.
This time, the researchers directly searched for cacao tree DNA in three samples. After sequencing and applying several filters to rule out other species, they identified sequences specific to Theobroma cacao (cacao tree) in two pottery fragments. The DNA fragments were very short, with characteristics matching ancient and degraded genetic material.
Caution is still necessary. Only two vessels provided enough cacao-specific sequences to exceed the threshold set by the researchers. The pottery had also been washed after its discovery in the 1950s. The team therefore applied strict procedures to limit the risk of modern DNA contaminating the samples.
The archaeological context provides another piece of information. These pots came from pits containing animal bones, pieces of pottery, and organic remains associated with feasts. The pits were later used during the construction of Etowah’s first large earthen mound. Cocoa may therefore have been consumed during communal gatherings.
Cocoa had already been identified much farther west, notably at Chaco Canyon, in what is now New Mexico. Etowah extends this presence to the southeastern United States. Yet no archaeological evidence has so far made it possible to trace a direct route between Etowah and the cacao-producing regions of Central America.
The researchers now want to search for cacao DNA at other sites. Pottery from the Ohio and Mississippi valleys, in particular, has previously yielded molecules compatible with cocoa, but also with yaupon holly. Genetic analysis could now determine whether cocoa circulated even more widely in North America before the arrival of Europeans.