Abstract:

Abstract Domestication is considered as a model of adaptation which can be used to draw conclusions about the modus operandi of selection in natural systems. Investigating domestication may give insights on how plants react to different intensities of human manipulation, which has direct implication for the ongoing efforts of crop improvement. Therefore, scientists of various disciplines study domestication related questions to understand its biological and cultural bases. We employed RAD-sequencing of 494 pea samples from all wild and domesticated groups to analyse the collection’s genetic structure. Patterns of ancient admixture were investigated by analysis of admixture graphs. We used two complementary approaches, one diversity based and one based on differentiation, to detect selection signatures putatively associated with domestication. Analysis of subpopulation structure of wild Pisum sativum exposed five distinct groups with a notable geographic pattern. Pisum abyssinicum clustered unequivocally within the P. sativum complex without indication for a hybrid origin. We detected 32 genomic regions putatively subjected to selection, 29 in P. sativum ssp. sativum and three in P. abyssinicum. The two domesticated groups did not share regions under selection and did not display similar haplotype patterns within those regions. Wild Pisum sativum is structured into well diverged subgroups. While P. s. ssp. humile is not supported as a taxonomic entity, the so-called 'southern humile' is a genuine wild group. Introgression did not shape the variation observed within the sampled germplam. The two cultivated pea groups display distinct genetic bases of domestication, suggesting two genetically independent domestication events.

Publisher's Version