The influences of progenitor filtering, domestication selection and the boundaries of nature on the domestication of grain crops

1. Domestication generally involves two sequential processes: initial identification of wild species with desirable characteristics (“progenitor filtering”); and subsequent artificial and natural selection that respectively improve features preferred by humans and adapt species to cultivation/captivity (“domestication selection”). Consequently, domesticated species can differ from wild species and may share characteristics owing to convergent evolution (“domestication syndrome”). Baring evolutionary constraints, domestication selection may generate extreme phenotypes that transcend the “boundaries of nature” evident for wild species. Despite evidence of domestication syndromes in some clades, broader contributions of progenitor filtering and domestication selection to characteristics of contemporary domesticated species have received limited attention.

2. Using comparative analysis of 49 grain-crop and 87 wild annual plant species from 15 families, we: (1) addressed whether plants of...