Researchers find cacao originated 1,500 years
earlier than previously thought
University of British Columbia
As we prepare to
feast on chocolate from the Halloween stash, a new study from an international team of researchers,
including the University of British Columbia, is pushing back the origins of
the delicious sweet treat.
The study, published online in Nature
Ecology & Evolution, suggests that cacao -- the plant from which
chocolate is made -- was domesticated, or grown by people for food, around
1,500 years earlier than previously thought. In addition, the researchers found
cacao was originally domesticated in South America, rather than in Central
America.
Archaeological evidence of cacao's
use, dating back to 3,900 years ago, previously planted the idea that the cacao
tree was first domesticated in Central America. But genetic evidence showing
that the highest diversity of the cacao tree and related species is actually
found in equatorial South America-where cacao is important to contemporary
Indigenous groups-led the UBC team and their colleagues to search for evidence
of the plant at an archaeological site in the region.
"This new study shows us that people in the upper reaches of the Amazon basin, extending up into the foothills of the Andes in southeastern Ecuador, were harvesting and consuming cacao that appears to be a close relative of the type of cacao later used in Mexico -- and they were doing this 1,500 years earlier," said Michael Blake, study co-author and professor in the UBC department of anthropology.
"They were also doing so using elaborate pottery that pre-dates the pottery found in Central America and Mexico. This suggests that the use of cacao, probably as a drink, was something that caught on and very likely spread northwards by farmers growing cacao in what is now Colombia and eventually Panama and other parts of Central America and southern Mexico."
Theobroma cacao, known as the cacao
tree, was a culturally important crop in pre-Columbian Mesoamerica -- a
historical region and cultural area in North America that extends from
approximately central Mexico through Belize, Guatemala, El Salvador, Honduras,
Nicaragua, and northern Costa Rica. Cacao beans were used both as currency and
to make the chocolate drinks consumed during feasts and rituals.
For the study, researchers studied
ceramic artifacts from Santa Ana-La Florida, in Ecuador, the earliest known
site of Mayo-Chinchipe culture, which was occupied from at least 5,450 years
ago.
The researchers used three lines of evidence to show that the Mayo-Chinchipe culture used cacao between 5,300 and 2,100 years ago: the presence of starch grains specific to the cacao tree inside ceramic vessels and broken pieces of pottery; residues of theobromine, a bitter alkaloid found in the cacao tree but not its wild relatives; and fragments of ancient DNA with sequences unique to the cacao tree.
The findings suggest that the
Mayo-Chinchipe people domesticated the cacao tree at least 1,500 years before
the crop was used in Central America. As some of the artifacts from Santa
Ana-La Florida have links to the Pacific coast, the researchers suggest that
trade of goods, including culturally important plants, could have started
cacao's voyage north.
Sonia Zarrillo, the study's lead
author and adjunct assistant professor at the University of Calgary who carried
out some of the research as a sessional instructor at UBC Okanagan's department
of anthropology, said the findings represent a methodological innovation in
anthropological research.
"For the first time, three
independent lines of archaeological evidence have documented the presence of
ancient cacao in the Americas: starch grains, chemical biomarkers, and ancient
DNA sequences," she said. "These three methods combine to
definitively identify a plant that is otherwise notoriously difficult to trace
in the archaeological record because seeds and other parts quickly degrade in
moist and warm tropical environments."
Discovering the origins of food that
we rely on today is important because it helps us understand the complex
histories of who we are today, said Blake.
"Today we all rely, to one
extent or another, on foods that were created by the Indigenous peoples of the
Americas," said Blake. "And one of the world's favourites is
chocolate."