International Symposium on Cocoa Research - ISCR 2022
Published November 27, 2023 | Version v1
Publication Open

Past domestication of T. cacao in Latin America revealed by paleo-genomics and methylxanthines analysis

Creators

  • 1. Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), UMR AGAP Institut, Montpellier, France
  • 2. UMR AGAP Institut, Univ Montpellier, CIRAD, INRAE, Institut Agro, Montpellier, France
  • 3. Museum National d'Histoire Naturelle (MNHN) - UMR 7206 Eco-anthropologie, Paris, France
  • 4. Institut des Biomolécules Max mousseron – (UMR IBMM), Université de Montpellier, Montpellier, France
  • 5. Museo Antropologico y de Arte Contemporaneo (MAAC), Guayaquil, Ecuador
  • 6. Museo Nacional de Colombia (MNC), Bogota, Colombia
  • 7. University of California, Davis, USA; Gaikwad Steroidomics Lab LLC, Davis, USA
  • 8. Department of Geography and Anthropology, Kennesaw State University Kennesaw, USA.
  • 9. Universidad Nacional Autónoma de México (UNAM), Mexico, Mexico
  • 10. Institut de Recherche pour le Développement (IRD), UMR 208 PALOC, MNHN-IRD, Paris, France
  • 11. Department of Anthropology, University of British Columbia, Vancouver, Canada.
  • 12. Asociación para la Investigación Científica de la Amazonía de Perú (ASICAMPE) - Perú
  • 13. The Univ. of Texas at Austin, Austin, USA
  • 14. Department of Anthropology and Archaeology, University of Calgary, Calgary, Canada
  • 15. Instituto Nacional de Investigaciones Agropecurias, INIAP, Ecuador

Description

Understanding the diversity of a species and its history, in order to better exploit it, is a challenge that breeders often face when creating new varieties adapted to the current environment. Many questions still remain about the first phases of cocoa domestication in Latin America. Using a multidisciplinary approach, associating archaeologists with genomics and biochemistry scientists, we tried to retrace the history of the past domestication of cocoa trees, and their migrations in South America and Central America. Plant paleo-genomics is a new field of research, that traces the evolution of cultivated plants in response to human domestication and natural selection since very ancient times. It is based on the analysis of ancient DNA (aDNA) from archaeological remains and can provide direct access to plant varieties consumed several thousand years ago. The oldest traces of cocoa consumption date back 5,500 years and have been identified in the southern Ecuadorian Amazon. New studies, reported in this paper, have been carried out from 382 archaeological samples collected mainly all along the Pacific coast of Ecuador and Colombia as well as in Central America and from diverse civilizations, the oldest of which dates back to more than 5000 years before present. Analyzes have revealed traces of ancient cocoa DNA and methylxanthines (theobromine, theophylline and caffeine) in the ceramic residues of many pre-Columbian cultures. They show a wide use of cocoa throughout the Latin America continent and at very varied times which can go back more than 5000 years. The genetic origin of varieties consumed several thousand years ago could have sometimes been identified by comparison with a large collection of modern genetic resources representing the diversity of the T. cacao species. These results provide new keys to unraveling the past domestication of T. cacao in Latin and Central America.

Keywords: T. cacao, ancient DNA, paleo-genomics, methylxanthines, domestication

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