Ancient DNA confirms a local origin of domesticated chenopod in eastern North America

Domesticated chenopod was an important starchy seed crop in eastern North America before the rise of maize agriculture. Domesticated chenopod first appeared in North America during the fourth millennium B.P., however its wild progenitor and site of domestication remain unresolved. Archaeological evidence suggests a local domestication in the Eastern Woodlands, while morphological similarities with modern Mexican cultivars indicate a possible introduction from Mesoamerica. To distinguish between these two scenarios, we isolate chloroplast DNA (cpDNA) from modern and archaeological North American chenopods sampled from across their geographic range. Our results demonstrate that the chenopod grown in the Eastern Woodlands was locally-derived, indicating that independent domestication events gave rise to the ancient eastern North American and modern Mexican cultivars. These results strengthen the argument for an entirely native pre-maize crop complex with chenopod as a major component.