Loss of reproductive organ separation zones as adaptation to Anthropogenic Seed-Dispersal-Based Mutualism

Domestication, or the evolutionary adaptation of organisms to anthropogenic ecosystems, is a key area of research that links the biological and social sciences. The domestication of a select few species of angiosperms (notably in Poaceae and Fabaceae) played a prominent role in driving the demographic and cultural changes that led humanity into the modern world. The earliest phenotypic changes in plants during the first stages of the domestication process in each of the independent centres of domestication around the world include: (i) an increase in seed size (possibly pleiotropically linked to an overall increase in plant mass) and (ii) a loss of traits for seed dispersal, notably a loss of function in separation zones, abscission or dehiscence, resulting in seeds that remain attached to the plant. Archaeobotanists and geneticists have heavily focused on the evolution of these two sets of traits, tracing out their timing and pathways towards introgression; however, there are still ongoing debates related to the role of humans in this process and what specific ecological factors during the transition to agriculture changed selective pressures. In this article, we review what is known about the ecology of seed-dispersal mechanisms in crop lineages before and after their adoption into cultivation systems; we specifically focus on abscission and dehiscence zones as archaeologically visible features directly associated with seed dispersal