Holocene land and sea-trade routes explain complex patterns of pre-Columbian crop dispersion.

ABSTRACT

Pre-Columbian crop movement remains poorly understood, hampering a good interpretation of the domestication and diversification of Neotropical crops. To provide new insights into pre-Columbian crop movement, we applied spatial genetics to identify and compare dispersal routes of three American crops between Mesoamerica and the Andes, two important centres of pre-Columbian crop and cultural diversity. Our analysis included georeferenced simple-sequence repeats (SSR) marker datasets of 1852 genotypes of cherimoya (Annona cherimola Mill.), a perennial fruit crop that became underutilised in the Americas after the European conquest, 770 genotypes of maize (Zea mays L.) and 476 genotypes of common bean (Phaseolus vulgaris L.). Our findings show that humans brought cherimoya from Mesoamerica to present Peru through long-distance sea-trade routes across the Pacific Ocean at least 4700 yr bp, after more ancient dispersion of maize and other crops through the Mesoamerican isthmus over land and near-coastal waters. To our knowledge, this is the first evidence of pre-Columbian crop movement between Mesoamerica and the Andes across the Pacific Ocean providing new insights into pre-Columbian crop exchange in the Americas. We propose that cherimoya represents a wider group of perennial fruit crops dispersed by humans via sea-trade routes between Mesoamerica and the Andes across the Pacific Ocean.