关键词: 物种形成, 物种概念, 地理物种形成, 合子后障碍, 交配系统

Abstract

Background & Aim: Speciation is a constant theme in the study of evolutionary biology. The nature of the dynamics and continuity of population evolution makes it hard to define the concept of species. Understanding the mechanisms of speciation remains crucial in the fields of evolutionary biology, taxonomy, conservation biology and biodiversity. Here we revisited the existent theories of speciation and reviewed the recent advances in empirical study.

Progresses: We discussed three geographical patterns of speciation (sympatric, parapatric, and allopatric speciation) and reviewed the corresponding empirical evidence from recent studies, based on the classical concept of biological species coined in terms of reproduction isolation. We further discussed the molecular genetics basis of postzygotic reproductive isolation and the evidence derived from analyses of applying population genomic data, including BDMI (Bateson-Dobzhansky-Muller incompatibility), QTLs (quantitative trait loci) analysis, Haldane’s rule and the large X-chromosome effects. We finally discussed the relationship between mating system, one of the pre-zygotic isolation barriers, and speciation. We inferred that selfing or inbreeding could drive speciation via either increasing population genetic differentiation or impeding gene flow between populations of different mating systems, or both.

Prospects: More evidence is needed to verify speciation theories. In addition, given the more frequent transitions to selfing from outcrossing in plant species, both flower characters and genomic differentiation could drive the so-called selfing syndromes. It is significant to clarify the role of mating system as a driver or as a reinforcer in plant speciation.

Key words: speciation, species concept, geographic speciation, postzygotic barrier, mating system