植物交配系统与分子进化理论及其应用研究

On the theories of plant mating system and molecular evolution and their applications

伴随着植物交配系统从异交向自交演化过程,植物花性状和基因组结构呈现自交综合征.本文系统探讨了形成有关综合征的理论基础与分子机制,分析了交配系统与不同进化过程互作基本理论.自交导致有效群体大小、突变率、重组率以及选择功效降低,但漂变效应、连锁不平衡等增强.这些理论较好地解释了同义和非同义突变相对比值变化、转座子数量变化、基因家族成员遗传相关性以及基因组结构特征.虽然分子标记被应用于交配系统参数估计,但交配系统研究与分子进化研究属于不同的研究领域,两者结合可形成一些重要生物学问题,如交配系统驱动与强化种间分子进化的作用模式、自交与异交植物分子进化模式差异、同种异质交配系统的群体间基因组结构差异等,澄清这些问题有助于深入理解交配系统在种内和种间分子进化过程中的作用.

With the transition of plant mating system from outcrossing to selfing, both the flower traits and genomic structure develop into selfing syndromes. Here we systematically discussed the theoretical basis and the molecular mechanisms that form these characteristics, and analyzed the basic theory of the interactions between mating system and different evolutionary processes. Selfing results in decrease in the effective population size, mutation rate, recombination rate and selection efficacy, but increase in genetic drift effects and linkage disequilibrium. These theories are effective in explaining the patterns of the relative rate of nonsynonymous to synonymous mutations, the change of the number of transposable elements, the genetic correlation between multigene family members and the pattern of genomic structure. Although molecular markers are often employed to score mating system, studies of mating system and molecular evolution have been mainly in different research fields. Some questions of biological significance could arise from an integration of these two research fields, such as the mode of driving or reinforcing molecular mechanism of speciation that the mating system operates, the different models of molecular evolution between populations of selfing versus outcrossing system, and the distinct genomic structure between populations of the same species with different mating systems. Clarification of these questions aids in our understanding of the role that mating system plays in affecting molecular evolution within and between species.