嘉宾（Guest）: Dr. Hongru Wang（汪鸿儒），IVPP
讨论主题（Topic）: The origin of rice domestication: single or multiple, that is the question
时间（Time）: 2017年1月4日 下午3:30—4:30（2017.1.4 3:30—4:30 pm）
地点（Location）: 南楼321室 （Room No.321, South Building）
Rice (Oryza sativa L.) is one of the most widely consumed staple food, especially in Asia. However, the domestication history of rice remains controversial with multiple studies reaching different conclusions regarding its origin(s). These studies have generally assumed that populations of living wild rice, O. rufipogon, are descendants of the ancestral population that gave rise to domesticated rice, but relatively little attention has been paid to the origin and history of wild rice itself. Here, we investigate the genetic ancestry of wild rice by analyzing a diverse panel of wild and domesticated rice genomes. We show that most modern wild rice is heavily admixed with domesticated rice through both pollen and seed mediated gene flow. In line with this hypothesis, many presumed wild rice varieties show remnants of the effects of selective sweeps in previously identified domestication genes. Furthermore, there is a distinct geographical pattern of gene flow from different domesticated rice subgroups into co-located wild rice. We also show that admixture from aus and indica (two domesticated rice subgroup) is more recent than gene flow from another subgroup, japonica, possibly consistent with an earlier spread of japonica varieties. We argue that wild rice populations should be considered a hybrid swarm, connected to domesticated rice by continuous and extensive gene flow. By incorporating the knowledge of gene flow into wild rice population, we re-interpret previous evidences for or against single origin of rice domestication, and we further propose a new model regarding rice domestication.
Fig. 1. A maximum-likelihoods tree for primary gene pool of rice domestication, with admixture events incorporated.