A new study from the University of British Columbia indicates that cacao was domesticated as a food source some 1,500 years earlier than previously thought. Furthermore, the scientists show that cacao was domesticated in South America, rather than in Central America. Earlier studies had shown the cacao tree dated back 3,900 years ago to Central America. New genetic evidence, however, reveals cacao tree and related species to have been around earlier in equatorial South America, by some 1,500 years.
Cacao tree
The cacao tree is a small tree, only growing to 4 to 8 meters in height. The seeds are called cocoa and are used to produce cocoa butter, the chocolate drink, as well as chocolate. Today the trees are grown in plantations in many tropical countries. he cacao tree’s botanical name is Theobroma cacao.
It takes around five years for the tree to bear fruit, has a peak growing period of 10 years, but can extend for decades. In 2016, according to the United Nations, cocoa beans were cultivated on 10,196,725 hectares (25,196,660 acres) worldwide, mostly on industrial plantations and from small farms. Chocolate can be made from T. cacao through a process of steps that involve harvesting, fermenting of T. cacao pulp, drying, harvesting, and then extraction.
New origins
With the new research, lead scientist Dr. Michael Blake tells Laboratory Manager magazine: “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.”
This finding was based on a study of ceramic artifacts from Santa Ana-La Florida, in Ecuador (representing early examples of Mayo-Chinchipe culture). The people of this time are believed to have traded plants with coastal cultures such as the Valdivia.
The researchers extracted residues of theobromine, which is a bitter alkaloid found in the cacao tree but not one found in wild relatives. Theobromine and caffeine, in the proportions found in cocoa, are responsible for the liking of the food/beverage. In addition, fragments of ancient DNA with sequences unique to the cacao tree were subject to genetic analysis.
The outcome of the laboratory tests represent the earliest evidence of T. cacao use in the Americas and the first archaeological example of the pre-Columbian use of cacao in South America. The findings additionally reveal the upper Amazon region as the oldest center of cacao domestication yet identified.
Research paper
The research has been published in the journal Nature Ecology & Evolution. The peer reviewed paper is titled “The use and domestication of Theobroma cacao during the mid-Holocene in the upper Amazon.”
Essential Science
This article is part of Digital Journal’s regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we looked at new evidence around the health risks of eating red meat. The specific substances that cause a build-up of plaque and which lead to arterial blockages have been identified by researchers. These substances cause an immune response which is linked to heart disease, and they derive from read meat.
The week before we saw how scientists have demonstrated how artificial intelligence can aid the automatic monitoring of single molecules in cells.
