壳斗目系统发育基因组学及多样化历史

	壳斗目系统发育基因组学及多样化历史; Phylogenomics and diversification history of Fagales
	杨莹莹
导师	伊廷双
摘要	The order Fagales belongs to the fabid clade within the rosids (core eudicots) and includes 1600 species (all of which are woody) distributed among 34 genera and 7 families. Many species of Fagales are keystone species and dominant components of forest ecological systems in both hemispheres. Previous molecular phylogenetic studies have greatly clarified our understanding of phylogenetic relationships within Fagales, but the phylogenetic positions of some families, subfamilies, and genera remain controversial. Examples include the phylogenetic position of Myricaceae, and some intergeneric relationships in Betulaceae, Juglandaceae, and Fagaceae. Many studies have explored the diversification of Fagales, but the underlying factors driving the observed patterns of diversification remain unclear. This thesis synthesized genomic (plastome, transcriptome, and nuclear) data, fossil evidence, morphological traits, and bioclimate variables to reconstruct phylogenetic relationships of Fagales, identify whole genome duplication events, examine morphological disparity, and to analyze correlations between species diversification and gene duplication, climate niche evolution, and trait evolution. The results from the major studies included in this thesis are outlined below. One study used plastomes of 256 species representing all seven families and 32 out of 34 genera of Fagales, 102 of which were assembled from newly sequenced transcriptomes, to reconstruct the phylogeny of Fagales. The results showed that Myricaceae and Juglandaceae are strongly supported as sister families. Some infrafamilial relationships, however, remained unclear: for example, the sister relationships of Alnus and Betula and the placement of Ostryopsis in Betulaceae, as well as intergeneric relationships in Myricaceae and Engelhardtioideae (Juglandaceae). Analyses of phylogenetic signal showed strong conflicts at four major contentious nodes in Betulaceae, Myricaceae, and Juglandaceae. These conflicts highlight the sensitivity of plastid phylogenomic analysis to genic composition, perhaps due to the signal heterogeneity across different regions of the plastome. Phylogenetic relationships in subfamily Quercoideae showed a geographical pattern, with Quercus being nonmonophyletic and its sections forming New World and Old World clades, respectively, with other co-distributed genera of Quercoideae. Our results suggest extensive ancient gene flow and chloroplast capture during the early diversification of major lineages of Quercus and Quercoideae. In another study, we used a transcriptomic/genomic dataset of 183 samples (148 were newly sequenced), including 158 species of Fagales representing all seven families and 32 of the 34 total genera, to reconstruct phylogenetic relationships within the order based on the nuclear genome. The results showed that Myricaceae and Juglandaceae are sisters (supporting the previous chloroplast relationship). In Betulaceae, a sister relationship between Alnu
	2021-11
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74553
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	杨莹莹. 壳斗目系统发育基因组学及多样化历史, Phylogenomics and diversification history of Fagales[D],2021.

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