社鼠亲缘地理关系与适应性进化

发布时间：2018-08-08 15:17

【摘要】：第四纪冰期对全球气候造成了巨大的改变,影响了物种的繁殖演化、地理分布格局以及种群间的遗传结构。近年来,亲缘地理学(Phylogeography)在推测物种的冰期避难所位置方面被广泛应用。本研究以社鼠为研究对象,探究其在冰期时的避难所及其间冰期的扩散路线从而为研究该物种种群间的演化过程提供理论基础,能够为生物多样性的保护提供理论基础。同时也探讨了温度以及相关指标纬度和海拔是否对社鼠线粒体基因在选择压力作用的作用下产生了适应性进化。本研究首先通过线粒体Cyt b基因对来自中国17省243只社鼠复合体体进行分子界定,分析分子鉴定为社鼠的地理种群间的亲缘关系、系统发育和历史演化动态,最后选取线粒体Cytb、ATP6和ATP8基因分析其在环境中的选择压力,进而探究社鼠的适应性进化。本文主要得到以下几个结论:(1)社鼠的种群分布范围明显地比传统认识的要小,在中国主要分布区应为云南、四川和长江以北地区。社鼠复合体种群在广西、山东、西藏和云南等地存在着隐存种。(2)社鼠的分化主要是由于青藏高原的隆起引起气候变化导致的,特别是昆黄运动后和冰期间冰期的多次回旋导致广泛分布的社鼠种群多次退缩和扩张,由地理隔离产生多个地理谱系结构,但在各谱系的分布区地理关系上仍有重叠。(3)在冰期时,社鼠在南北方存在着多个避难所,但避难所之间依然存在着少数通道,能够进行基因交流。末次冰期后,随着气候的回暖北方气候的干燥,分布在华北地区的社鼠向东北和南扩张至长江一线。而存在于四川中部的群体则向东扩散。(4)选择压力分析,社鼠在选择上主要受纯化选择的作用。线粒体Cytb和ATPase在温度、纬度和海拔上并没有表现出相应的变化趋势。通过本研究证实以传统形态学鉴定为社鼠的群体实则为社鼠复合体,而分布在长江以南地区的社鼠与海南白腹鼠N.lotipes构成单系群。社鼠的演化是由于青藏高原隆起,冰期间冰期的多次回旋事件导致中国大陆气候发生强烈地变化而在各自分布区内产生谱系分化。广泛分布的社鼠在适应环境各自分布区的环境形成其特有分布区的适应机制,与高原土著动物的适应性进化有着不同的分子适应机制。
[Abstract]:The Quaternary glacial period caused great changes to the global climate, which affected the reproduction and evolution of species, geographical distribution pattern and genetic structure among populations. In recent years, phylogenetic (Phylogeography) has been widely used to speculate on the location of glacial havens of species. In order to provide theoretical basis for the study of the evolution process of the species during the interglacial period and to provide a theoretical basis for the conservation of biodiversity, this study takes the rodent as the research object, and explores its refuge during the glacial period and its diffusion route during the interglacial period. At the same time, it was also discussed whether temperature, latitude and altitude could produce adaptive evolution of mitochondrial gene under selective pressure. In this study, the mitochondrial Cyt b gene was used to define the complex of 243 mice from 17 provinces in China, and the phylogenetic relationship, phylogeny and historical evolution of the population were analyzed. Finally, the selection pressure of mitochondrial Cytbtbtaphane ATPase 6 and ATP8 gene in the environment was analyzed, and the adaptive evolution of the mice was explored. The main conclusions of this paper are as follows: (1) the population distribution range of rodents is obviously smaller than that of traditional knowledge, and the main distribution areas in China should be Yunnan, Sichuan and the north of the Yangtze River. In Guangxi, Shandong, Tibet, Yunnan and other places, there are hidden species of rodent complex. (2) the differentiation of rodent is mainly caused by climate change caused by the uplift of Qinghai-Xizang Plateau. Especially after the Kun Huang Movement and the interglacial period, the widely distributed rodent population retreated and expanded many times, resulting in multiple geographical lineages from geographical isolation. But there is still overlap in the geographical relationship between the distribution regions of each pedigree. (3) during the glacial period, there were many shelters in the south and north, but there were still a few channels between the shelters, which were able to communicate with each other. After the last glacial period, with the warming of the northern climate, the rodents distributed in North China spread to the northeast and south to the Yangtze River. The population in the middle of Sichuan spread eastward. (4) selection pressure analysis showed that the selection of rodents was mainly affected by purification selection. Mitochondrial Cytb and ATPase did not show a corresponding trend in temperature, latitude and altitude. In this study, it was proved that the group identified by the traditional morphology as the rodent complex was actually a rodent complex, while the N.lotipes from the south of the Yangtze River constituted a monophyletic group. The evolution of the rodent is due to the uplift of the Qinghai-Tibet Plateau and the repeated interglacial events in the interglacial period, which led to the strong changes in the climate of the Chinese continent and the lineage differentiation in their respective distribution areas. The widely distributed rodents formed their own adaptive mechanisms in their respective distribution areas, which were different from the adaptive evolution of plateau native animals.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q958

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