瑞香狼毒（Stellera chamaejasme L.）物种分化机制的研究

	瑞香狼毒（Stellera chamaejasme L.）物种分化机制的研究
	Santosh Kumar Rana Magar
导师	孙航
关键词	cryptic morphs, Pleistocene glaciation, population, RAD-seq, speciation, Stellera chamaejasme, ‘Third Pole’, transcriptome
摘要	Elucidating species’ differentiation and evolution mechanism using the fine-scale exploration of population genomics in the ‘Third Pole’ remains largely enigmatic. The high species diversity in this so-called ‘Third Pole’ has long been attributed to a complex set of factors. Recent large-scale macroevolutionary studies have placed potentially (much) older bounds on diversity and an extended window of time when in fact this diversity is much younger. More often, the interplay of Pleistocene glaciation with abiotic (orogeny, climate) and additional biotic factors exists in the ideal mountain systems for the evolutionary mechanisms of speciation. Nevertheless, dissecting the genetic variation across the compartmentalized landscapes is critical for understanding the population differentiation and identifying the genomic architecture. Despite our understanding of this region’s diversification, finer-scale population-level investigations are lacking for better illuminating the genomic basis for the differentiation and evolution of cryptic species. Therefore, the comparative population genomic study can contribute to in-depth exploration of the mechanism leading to species variation and population differentiation based on genomic evidence through RNA-seq/RAD-seq data, in association with eco-morphological analyses. Here, with integration of RAD-seq and eco-morphological data for the polymorphic taxa Stellera chamaejasme L. (Thymelaeaceae), surprisingly uncover four cryptic species and implicate a complex set of interacting factors likely influencing allopatric speciation, mountain building north-south migration tracking glaciation shift, and pollinator-mediated diversification. Contrary to other mountains, the plants of Hengduan Mountains-Qinghai Tibetan Plateau (HM-QTP) exhibit a mode of ice-age-driven allopatric speciation and unveil the north-south/up-down migration triggered by the tempo of Pleistocene glacial-interglacial episodes. Further, the macroevolutionary evidence from phylogenomic and evolutionary investigation inferred that the Pleistocene (tempo) allopatric speciation (mode) is the consequence of glacial cooling apart from orogeny and monsoonal events. Our study highlighted the many uncharacterized cryptic species in this mountain cradle of diversification and has narrowed down the broad time scale of species evolution to a younger time scale since the Pleistocene. We also characterized the gene expression variation as the basis for population differentiation across the four intuitive cryptic species morphs of Stellera chamaejasme using RNA-seq transcriptomic population datasets. We generated population transcriptome data from 144 cDNA libraries and pooled them from different tissues (Flower, Leaf, Root, Stem). The Trinity de novo assembly identified 507384 (PP morph), 427096 (YY morph), 370367 (YW morph), and 296855 (RW morph) differentially expressed genes. ....................
语种	英语
	2022-07
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/151853/75210
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	Santosh Kumar Rana Magar. 瑞香狼毒（Stellera chamaejasme L.）物种分化机制的研究[D]. 中国科学院大学,2022.

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