An integrated archaeogenomic view of squash and gourd (Cucurbita spp.) natural history, biogeography, and domestication

Squashes, pumpkins, and various gourds in the genus Cucurbita were domesticated on at least six independent occasions throughout the Americas, beginning ~10,000 years ago in southern Mesoamerica. They came to play major roles in prehistoric food production systems throughout North, Central, and South America, and are now produced at both subsistence and commercial scales worldwide. We present genome-scale DNA sequence data from diverse modern and archaeological specimens aimed at questions of natural history and domestication in the Cucurbita. We securely confirm eastern North America as an independent Cucurbita pepo domestication center; we suggest a widespread, protracted pattern for C. moschata throughout the circum-Caribbean zone; and, we identify a possible cultigen from northern Mexico that is previously unrecognized and now extinct. Finally, wild Cucurbita populations have declined dramatically during the Holocene. We attribute this decline to rapid ecological shifts, including climate change and the extinction of the wild plants’ megafaunal dispersers.