Cacao DNA found in 11th-century pottery at Georgia's Etowah Mounds, a first east of the Mississippi

Mixed · 2A study published in PLOS One on August 26 reports genetic analysis of pottery fragments from near the Etowah Indian Mounds in Georgia that revealed the earliest known evidence of cacao, the source of chocolate, east of the Mississippi River. 1 2 Mixed · 2Etowah, just northwest of Atlanta, has six earthen monuments built by Native Americans in the pre-Columbian Mississippian period; archaeologist Adam King of the University of South Carolina says building them was likely highly ritualised, with the mounds possibly representing the Earth. 1 2 Mixed · 2In the 1950s archaeologists found the remains of a feast, including animal bones and pottery sherds, dating to between 1050 and 1150 CE in a borrow pit, a hole left after clay was dug for mound building. The sherds were washed and stored for decades but kept traces of their former contents. 1 2

Mixed · 2King and colleague Terry Powis obtained permission from the Muscogee people, for whom Etowah is sacred, to test the sherds. 1 2 Mixed · 2Mass spectrometry found compounds associated with cacao in the 31 sherds tested. Times of India lists four (theobromine, theophylline, caffeine and paraxanthine) and says almost half of the samples held at least two of them; GB News says caffeine appeared in all 31. 1 2 Right · 1GB News adds that caffeine also occurs in American holly species such as yaupon holly, traditionally brewed as tea in the south-eastern US, and that the researchers initially favoured yaupon as the likelier source. To resolve this they worked with French scientists on DNA analysis. 2

Mixed · 2The DNA analysis identified highly fragmented ancient Theobroma cacao DNA in two sherds. Times of India says three fragments were analysed and yielded more than 502 million useful paired sequences. 1 2 Mixed · 2The researchers took precautions against modern contamination; GB News says the DNA was degraded in a way consistent with material about a thousand years old, and quotes Barbara Mills, professor emerita of archaeology at the University of Arizona, praising how carefully they addressed the issue. 1 2 Mixed · 2Cacao originated in Mesoamerica, with domestication evidence going back about 5,300 years in Ecuador and fermented chocolate drinks made by the Olmecs by 1500 BCE; the Maya used beans as currency. Evidence for cacao in North America had been limited. 1 2

Mixed · 2How the cacao reached Georgia is unknown. King said a traveller may have carried it directly or it may have passed through successive exchanges. Cacao residue found earlier at Pueblo Bonito in Chaco Canyon, New Mexico, dates to a similar period, suggesting possible continental trade networks; Times of India also raises Gulf Coast and Caribbean-Florida routes. 1 2 Centre · 1Times of India notes the Etowah vessels differ from Maya or Ancestral Puebloan chocolate vessels, so how they were used beyond a feast context is unclear. It also quotes the authors urging renewed study of contacts with Central and South America, "without denying the achievements of Mississippian people". 1