Cargando…
Present Spatial Diversity Patterns of Theobroma cacao L. in the Neotropics Reflect Genetic Differentiation in Pleistocene Refugia Followed by Human-Influenced Dispersal
Cacao (Theobroma cacao L.) is indigenous to the Amazon basin, but is generally believed to have been domesticated in Mesoamerica for the production of chocolate beverage. However, cacao’s distribution of genetic diversity in South America is also likely to reflect pre-Columbian human influences that...
Autores principales: | , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2012
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3480400/ https://www.ncbi.nlm.nih.gov/pubmed/23112832 http://dx.doi.org/10.1371/journal.pone.0047676 |
_version_ | 1782247551036030976 |
---|---|
author | Thomas, Evert van Zonneveld, Maarten Loo, Judy Hodgkin, Toby Galluzzi, Gea van Etten, Jacob |
author_facet | Thomas, Evert van Zonneveld, Maarten Loo, Judy Hodgkin, Toby Galluzzi, Gea van Etten, Jacob |
author_sort | Thomas, Evert |
collection | PubMed |
description | Cacao (Theobroma cacao L.) is indigenous to the Amazon basin, but is generally believed to have been domesticated in Mesoamerica for the production of chocolate beverage. However, cacao’s distribution of genetic diversity in South America is also likely to reflect pre-Columbian human influences that were superimposed on natural processes of genetic differentiation. Here we present the results of a spatial analysis of the intra-specific diversity of cacao in Latin America, drawing on a dataset of 939 cacao trees genotypically characterized by means of 96 SSR markers. To assess continental diversity patterns we performed grid-based calculations of allelic richness, Shannon diversity and Nei gene diversity, and distinguished different spatially coherent genetic groups by means of cluster analysis. The highest levels of genetic diversity were observed in the Upper Amazon areas from southern Peru to the Ecuadorian Amazon and the border areas between Colombia, Peru and Brazil. On the assumption that the last glaciation (22,000–13,000 BP) had the greatest pre-human impact on the current distribution and diversity of cacao, we modeled the species’ Pleistocene niche suitability and overlaid this with present-day diversity maps. The results suggest that cacao was already widely distributed in the Western Amazon before the onset of glaciation. During glaciations, cacao populations were likely to have been restricted to several refugia where they probably underwent genetic differentiation, resulting in a number of genetic clusters which are representative for, or closest related to, the original wild cacao populations. The analyses also suggested that genetic differentiation and geographical distribution of a number of other clusters seem to have been significantly affected by processes of human management and accompanying genetic bottlenecks. We discuss the implications of these results for future germplasm collection and in situ, on farm and ex situ conservation of cacao. |
format | Online Article Text |
id | pubmed-3480400 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-34804002012-10-30 Present Spatial Diversity Patterns of Theobroma cacao L. in the Neotropics Reflect Genetic Differentiation in Pleistocene Refugia Followed by Human-Influenced Dispersal Thomas, Evert van Zonneveld, Maarten Loo, Judy Hodgkin, Toby Galluzzi, Gea van Etten, Jacob PLoS One Research Article Cacao (Theobroma cacao L.) is indigenous to the Amazon basin, but is generally believed to have been domesticated in Mesoamerica for the production of chocolate beverage. However, cacao’s distribution of genetic diversity in South America is also likely to reflect pre-Columbian human influences that were superimposed on natural processes of genetic differentiation. Here we present the results of a spatial analysis of the intra-specific diversity of cacao in Latin America, drawing on a dataset of 939 cacao trees genotypically characterized by means of 96 SSR markers. To assess continental diversity patterns we performed grid-based calculations of allelic richness, Shannon diversity and Nei gene diversity, and distinguished different spatially coherent genetic groups by means of cluster analysis. The highest levels of genetic diversity were observed in the Upper Amazon areas from southern Peru to the Ecuadorian Amazon and the border areas between Colombia, Peru and Brazil. On the assumption that the last glaciation (22,000–13,000 BP) had the greatest pre-human impact on the current distribution and diversity of cacao, we modeled the species’ Pleistocene niche suitability and overlaid this with present-day diversity maps. The results suggest that cacao was already widely distributed in the Western Amazon before the onset of glaciation. During glaciations, cacao populations were likely to have been restricted to several refugia where they probably underwent genetic differentiation, resulting in a number of genetic clusters which are representative for, or closest related to, the original wild cacao populations. The analyses also suggested that genetic differentiation and geographical distribution of a number of other clusters seem to have been significantly affected by processes of human management and accompanying genetic bottlenecks. We discuss the implications of these results for future germplasm collection and in situ, on farm and ex situ conservation of cacao. Public Library of Science 2012-10-24 /pmc/articles/PMC3480400/ /pubmed/23112832 http://dx.doi.org/10.1371/journal.pone.0047676 Text en © 2012 Thomas et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Thomas, Evert van Zonneveld, Maarten Loo, Judy Hodgkin, Toby Galluzzi, Gea van Etten, Jacob Present Spatial Diversity Patterns of Theobroma cacao L. in the Neotropics Reflect Genetic Differentiation in Pleistocene Refugia Followed by Human-Influenced Dispersal |
title | Present Spatial Diversity Patterns of Theobroma cacao L. in the Neotropics Reflect Genetic Differentiation in Pleistocene Refugia Followed by Human-Influenced Dispersal |
title_full | Present Spatial Diversity Patterns of Theobroma cacao L. in the Neotropics Reflect Genetic Differentiation in Pleistocene Refugia Followed by Human-Influenced Dispersal |
title_fullStr | Present Spatial Diversity Patterns of Theobroma cacao L. in the Neotropics Reflect Genetic Differentiation in Pleistocene Refugia Followed by Human-Influenced Dispersal |
title_full_unstemmed | Present Spatial Diversity Patterns of Theobroma cacao L. in the Neotropics Reflect Genetic Differentiation in Pleistocene Refugia Followed by Human-Influenced Dispersal |
title_short | Present Spatial Diversity Patterns of Theobroma cacao L. in the Neotropics Reflect Genetic Differentiation in Pleistocene Refugia Followed by Human-Influenced Dispersal |
title_sort | present spatial diversity patterns of theobroma cacao l. in the neotropics reflect genetic differentiation in pleistocene refugia followed by human-influenced dispersal |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3480400/ https://www.ncbi.nlm.nih.gov/pubmed/23112832 http://dx.doi.org/10.1371/journal.pone.0047676 |
work_keys_str_mv | AT thomasevert presentspatialdiversitypatternsoftheobromacacaolintheneotropicsreflectgeneticdifferentiationinpleistocenerefugiafollowedbyhumaninfluenceddispersal AT vanzonneveldmaarten presentspatialdiversitypatternsoftheobromacacaolintheneotropicsreflectgeneticdifferentiationinpleistocenerefugiafollowedbyhumaninfluenceddispersal AT loojudy presentspatialdiversitypatternsoftheobromacacaolintheneotropicsreflectgeneticdifferentiationinpleistocenerefugiafollowedbyhumaninfluenceddispersal AT hodgkintoby presentspatialdiversitypatternsoftheobromacacaolintheneotropicsreflectgeneticdifferentiationinpleistocenerefugiafollowedbyhumaninfluenceddispersal AT galluzzigea presentspatialdiversitypatternsoftheobromacacaolintheneotropicsreflectgeneticdifferentiationinpleistocenerefugiafollowedbyhumaninfluenceddispersal AT vanettenjacob presentspatialdiversitypatternsoftheobromacacaolintheneotropicsreflectgeneticdifferentiationinpleistocenerefugiafollowedbyhumaninfluenceddispersal |