连翘的亲缘地理学与景观遗传学研究

发布时间：2019-04-24 15:48

【摘要】：中国暖温带地区拥有大量本土的落叶阔叶树种,但对于这一地区物种的亲缘地理学研究还没有得到广泛重视。连翘(Forsythia suspensa)为多年生落叶灌木,属木犀科(Oleaceae)连翘属(Forsythia)植物,广泛分布于我国河北、山西、陕西、山东、安徽西部、河南、湖北、四川等地,平均海拔为300-2200米,是我国暖温带地区具有代表性的植物。因此,在本研究中选择连翘作为研究对象,对中国暖温带植被的亲缘地理历史进行研究,以探讨更新世时期气候波动对该落叶阔叶树种分布变化的影响。选用两个叶绿体DNA(cpDNA)片段,一个核糖体DNA(nrDNA)片段和生态位模型来研究连翘的亲缘地理模式。此项研究的具体目标是解决以下问题:(一)cpDNA和nrDNA数据所揭示的连翘种群在中国的遗传结构;(二)中国暖温带地区连翘如何应对更新世时期的气候波动。cpDNA数据显示出7个地理界线明显的亲缘地理类群,但与cpDNA数据不同的是,nr DNA数据将样本聚类为3个遗传类群。生态位模型表明连翘在寒冷时期的气候适宜区比在温暖时期的面积要大。分子数据和生态位模型表明,连翘在冰期向附近低海拔平原地区扩张,在较温暖的间冰期阶段退回到山顶区域。与更新世冰期长途向南迁移或大规模缩小分布范围的假说相反,本研究认为连翘在冰期坚持在原地生存。了解物种的遗传多样性和遗传结构模式对于物种的有效管理和保护起着极其重要的作用。在本研究中,采用9个微卫星位点研究连翘的遗传多样性和结构。结果显示,由于人类对连翘果实的过度采摘,连翘的遗传多样性(HT=0.721)比中国其他种子植物的遗传多样性低。微卫星数据还显示出连翘种群内有显著的种群分化(FST=0.113,P0.001)。Mantel检测和冗余分析表明,地理距离和温度对连翘种群的遗传分化起到显著的促进作用。对种群结构进行贝叶斯分析,可以将连翘分为两个遗传类群。生态位模型表明,这两个遗传类群的隔离是由于中间地带较低的气候适宜区隔离造成的。基于连翘的遗传信息,我们建议可以将具有较高水平遗传多样性和大量稀有等位基因的种群优先进行保育。
[Abstract]:There are a large number of deciduous broad-leaved tree species in warm temperate regions of China, but the genetic geography of species in this area has not been paid much attention. Forsythia forsythia (Forsythia suspensa) is a perennial deciduous shrub, belonging to (Forsythia) plant of (Oleaceae) family. It is widely distributed in Hebei, Shanxi, Shaanxi, Shandong, western Anhui, Henan, Hubei, Sichuan and other places with an average elevation of 300? 2200m. It is a representative plant in warm temperate zone of China. Therefore, Forsythia forsythia was selected as the research object to study the phylogenetic history of warm temperate vegetation in China in order to explore the influence of climate fluctuation on the distribution of this deciduous broad-leaved tree during the Pleistocene period. Two chloroplast DNA (cpDNA) fragments, one ribosomal DNA (nrDNA) fragment and niche model were used to study the phylogenetic model of Forsythia suspensa. The specific objectives of this study were to solve the following problems: (1) genetic structure of Forsythia forsythia population revealed by cpDNA and nrDNA data in China; (2) how to deal with climate fluctuation of Forsythia forsythia in warm temperate regions of China during the Pleistocene period. CpDNA data showed seven geographical groups with obvious geographical boundaries, but different from cpDNA data, the samples were clustered into three genetic groups by, nr DNA data. Niche model showed that the area of climate-suitable area of Forsythia forsythia in cold period was larger than that in warm period. The molecular data and niche model showed that Forsythia forsythia extended to the nearby low altitude plain during the ice age and returned to the top of the mountain during the warmer interglacial period. Contrary to the hypothesis of long-distance southward migration or large-scale narrowing of the distribution of Forsythia forsythia during the Pleistocene ice age, the present study suggests that Forsythia forsythia persevered in Understanding the genetic diversity and genetic structure of species plays an important role in the effective management and conservation of species. In this study, 9 microsatellite loci were used to study the genetic diversity and structure of Forsythia suspensa. The results showed that the genetic diversity (HT=0.721) of Forsythia suspensa was lower than that of other seed plants in China due to the excessive picking of Forsythia suspensa fruits. Microsatellite data also showed that there was significant population differentiation (FST=0.113,P0.001) in Forsythia suspensa population. Mantel detection and redundancy analysis showed that geographical distance and temperature played a significant role in promoting genetic differentiation of Forsythia suspensa population. By Bayesian analysis of population structure, Forsythia forsythia can be divided into two genetic groups. The niche model shows that the isolation of the two genetic groups is due to the isolation of the lower climatic suitability zone in the middle zone. Based on the genetic information of Forsythia forsythia, we suggest that populations with high level of genetic diversity and a large number of rare alleles can be preferred for conservation.
【学位授予单位】：河南农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S685.24

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