迎阳报春复合群遗传标记开发和应用

	迎阳报春复合群遗传标记开发和应用
	曾志华
导师	周伟
关键词	异型花柱 Heterostyly 遗传标记开发 Genetic marker development 交配系统 Mating system 表型自交综合征 Phenotypic selfing syndrome 遗传自交综合征 Genetic selfing syndrome
摘要	在被子植物中，交配系统由异交向自交的转变频繁发生，但专性自交的物种仅占10~15%。自交物种多次起源，却很少能长期存留，有学者提出自交物种的“进化盲端假说”，认为自交是生物进化的死胡同。交配系统转变为自交，在基因组水平会留下特定的遗传效应，长期维持自交的物种，其表型也会因为繁殖资源投入降低发生一系列转变。在报春花属中，通常认为异型花柱以异交为主，在异型花柱中的特殊表型同型花住类群通常以自交为主。本研究选取了兼具异型花柱和同型花柱的迎阳报春及其近缘种同型的灌丛报春组成复合群。利用一代、二代测序技术和形态学测量，开发适用于交配系统转变研究的四种遗传标记，具体为基于一代测序的微卫星遗传标记，基于二代测序的叶绿体基因组和转录组遗传标记，以及基于花部性状的形态学标记。同时将四种遗传标记应用于自交综合征起源的研究中，探讨交配系统转变的遗传效应和表型特征。主要结论包括： 1．同型花柱类群的多次独立起源叶绿体基因组构建单倍型系统发育框架，微卫星遗传标记构建的遗传距离邻近树和转录组遗传距离邻近树结果显示，在迎阳报春复合群内，同型花柱类群为复合群的衍生特征，经历多次独立起源。复合群同型花柱的起源存在时间先后关系，灌丛报春属于早期起源，同型的迎阳报春属于近期起源。 2．在遗传水平，复合群内同型花柱类群表现出不同程度的遗传自交综合征发育信号叶绿体基因组、微卫星和转录组三种遗传标记研究结果显示，在两个同型花柱谱系中，自交率显著升高，核苷酸多样性、等位基因数目和杂合度降低，连锁不平衡程度增加。但遗传结构研究结果显示，迎阳报春异型和同型间没有明显的分界线。在复合群中，迎阳报春同型花柱遗传自交综合征的发育还不完备，灌丛报春已经表现出完整的自交综合征信号。可见，遗传自交综合征的发育与自交发生的时间有关。 3．在表型特征方面，两个同型花柱类群表现出明显表型自交综合征通过花部性状的形态学标记，三个谱系867个样本的花部性状间存在较大变异。同型的灌丛报春中检测到明显的自交综合征发育信号，迎阳报春同型谱系中虽部分性状自交综合(胚珠数量、花色和花粉大小)没有显著的自交综合征信号，但已经具备自交综合征的基本特征。由此可知，表型自交综合征的发育同样依赖自交的持续时间。综上所述，通过四种遗传标记，在迎阳报春复合群内部检测到交配系统转变后表型和遗传自交综合征的发育信号，为异型花柱类群报春花属植物自交综合征的起源和进化提供充分的证据。; In angiosperms, the transition of mating system from outcrossing to selfing occurs frequently, but only 10-15% of species are obligately selfed. Selfing originates independently for many times, but rarely survives for a long time. Some scholars have proposed the "evolutionary dead end hypothesis" of selfing species, arguing that selfing is a dead end in biological evolution. The transition of the mating system to selfing leaves specific genetic effects at the genomic level, and the phenotypes of species that maintain self-pollination over a long period of time also undergo a series of changes due to reduced investment in reproductive resources. In the Primula L., it is generally considered that the distyly is dominated by outcrossing, and the homostyly are usually dominated by selfing. To explore the genetic effects and phenotypic characteristics of mating system transitions, Primula oreodoxa with both distyly and homostyly styles and its close related Primula dumicola were selected to form a complex. Four genetic markers suitable for the study of mating system transition were developed by using first-generation and second-generation sequencing technology and morphological measurement. Specifically, microsatellite genetic markers based on first-generation sequencing, chloroplast genome and transcriptome genetic markers based on second-generation sequencing, and morphological markers based on flower traits. At the same time, four genetic markers were applied to the study of the origin of inbreeding syndrome to explore the genetic effects and phenotypic characteristics of mating system transition. The main results and conclusions as follows: 1. Homostyly undergo multiple independent origins The haplotype phylogenetic framework of chloroplast genome, and the genetic distance neighbor joining tree of microsatellite genetic markers and transcriptome, showed that the homostyly was a derived feature of the complex group and experienced multiple independent origins within the complex. In the complex, the origins of the homostyly had a chronological relationship, Primula dumicola belonged to the early origin, and the homostyly of Primula oreodoxa belonged to the recent origin. 2. At the genetic level, homostyly exhibit different degrees of genetic selfing syndrome signals The results of three genetic markers of chloroplast genome, microsatellites and transcriptome showed that in the two homotypic lineages, the selfing rate was significantly increased, the nucleotide diversity, the number of alleles and the heterozygosity were decreased, and the degree of linkage disequilibrium was decreased. However, the results of the genetic structure study showed that there was no clear dividing line between the distyly and the homostyly of Primula oreodoxa. In the complex, the development of homostyly genetic selfing syndrome in Primula oreodoxa was not complete, and Primula dumicola had already shown a complete signal of selfing syndrome.
语种	中文
	2022-05
学位授予单位	中国科学院大学
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/75123
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	曾志华. 迎阳报春复合群遗传标记开发和应用[D]. 中国科学院大学,2022.

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