Abstract
Plant domestication can be seen as a long-term process that involves a complex interplay among demographic processes and evolutionary forces. Previous studies have suggested two domestication scenarios for Lima bean in Mesoamerica: two separate domestication events, one from gene pool MI in central-western Mexico and another one from gene pool MII in the area Guatemala-Costa Rica, or a single domestication from gene pool MI in central-western Mexico followed by post-domestication gene flow with wild populations. In this study we evaluated the genetic structure of the wild gene pool and tested these two competing domestication scenarios of Lima bean in Mesoamerica by applying an ABC approach to a set of genome-wide SNP markers. The results confirm the existence of three gene pools in wild Lima bean, two Mesoamerican gene pools (MI and MII) and the Andean gene pool (AI), and suggest the existence of another gene pool in central Colombia. The results indicate that although both domestication scenarios may be supported by genetic data, higher statistical support was given to the single domestication scenario in central-western Mexico followed by admixture with wild populations. Domestication would have involved strong founder effects reflected in loss of genetic diversity and increased LD levels in landraces. Genomic regions affected by selection were detected and these may harbor candidate genes related to domestication.
Highlights
Domestication can be seen as a complex interplay among demographic processes and evolutionary forces that increase the adaptation of wild populations to human-driven environments (Purugganan and Fuller, 2009; Larson and Burger, 2013; Meyer and Purugganan, 2013; Wang et al, 2017)
As stated in materials and methods, in order to establish the presence of domestication candidate genes within the regions detected by varLD, we counted the number of genes that displayed domestication signatures in P. vulgaris, according to the results reported by Schmutz et al (2014), and we evaluated whether the function of these genes was or not related to domestication on the basis of the function reported for Arabidopsis thaliana
Previous studies have established that the Andean gene pool Andean I (AI) is ancestral to Mesoamerican II gene pool (MII) and Mesoamerican I gene pool (MI) (Serrano-Serrano et al, 2010), and in this context gene pool another gene pool in central Colombia (AII) takes relevance to understand the evolutionary history of wild Lima bean and its spread to Mesoamerica from the Andes, additional accessions from central Colombia should be studied in more detail
Summary
Domestication can be seen as a complex interplay among demographic processes and evolutionary forces that increase the adaptation of wild populations to human-driven environments (Purugganan and Fuller, 2009; Larson and Burger, 2013; Meyer and Purugganan, 2013; Wang et al, 2017). Several questions about domestication have been of interest to evolutionary biologists. One of these questions is the number of times a crop species was domesticated. The traditional approach to address this question has been the identification of monophyletic clusters of extant crop representatives as evidence of single domestication. This approach may be misleading because the extent of genetic drift and gene flow (for example among independent cultivation sites) may be effective in erasing early genetic signals of multiple domestications (Allaby et al, 2008; Olsen and Gross, 2008).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
