黑藻属的分子谱系及其生物地理研究

发布时间：2018-05-17 19:01

本文选题：黑藻 + 谱系地理　；参考：《武汉大学》2015年博士论文

【摘要】：水生植物由于其特殊的生境而具有与陆生植物不同的进化历程。目前已有不少的研究利用分子谱系地理研究来探讨水生植物进化,但是很少涉及大地理尺度下的水生植物广布种。本研究以黑藻属为研究对象,其为单型属仅有一个广布种黑藻,在中国进行样品采集,调查其详细的地理分布；以叶绿体基因片段和微卫星位点为分子标记,研究黑藻在中国的遗传多样性和基因谱系地理分布格局；结合其他地区黑藻的叶绿体基因片断序列,推断黑藻的生物地理历史：比较黑藻种内不同遗传分支的形态数据,探讨是否存在种内分化。主要结果如下：1)黑藻分布于东北至西南一线向东的广大地区。利用叶绿体片段trnL-F分析这地区的123个黑藻种群的遗传多样性和谱系地理结构。发现黑藻具有较高的遗传多样性(Hd=0.608,Pi=0.0038)和遗传分化系数(Fsr=0.820),绝大部分遗传变异来源于种群间,仅有17.97%的遗传变异来源于种群内。划分为九大流域来进行比较,则长江流域和东南沿海流域的遗传多样性最高,黑龙江流域、辽河和海河流域、黄河流域的遗传多样性最低,其遗传多样性为0。在123个种群的681个个体中共得到9个单倍型,这些单倍型明显分为4支(A.B.C.D支),且每一支有各自的分布范围,表明黑藻具有显著的谱系地理结构(NsTGsT,p0.01)。2)利用自行开发的5对微卫星引物和文献报道的3对微卫星引物对黑藻的遗传多样性和遗传结构进一步研究。选取了遍布整个分布区的57个种群共834个个体,同时也结合了上一章的部分叶绿体数据。发现黑藻共有66个基因型,22个种群都由单个基因型组成,表明黑藻以无性繁殖为主。克隆多样性指数D为0.269(0到0.764),遗传分化系数GsT为0.2853。分子方差分析表明黑藻种群内和种群间遗传差异相似,分别占全部遗传差异的52%和48%。遗传结构分析揭示了黑藻种群可以根据其地理分布分为两个遗传群：南方群(长江以南)和北方群(主要在长江以北),分别对应叶绿体基因片段的A支+B支和C支+D支。两种分子标记都揭示种群之间遗传距离与地理距离显著正相关但是在各自遗传群内则不相关,表明两大遗传群之间基因交流有限。3)结合其他地区的trnL-F序列对黑藻的生物地理历史进行推断。得到的14个单倍型在系统发育树上分为A、B、C和D四支。根据化石校准点估算,黑藻大约在中新世后期(6.71 Ma)开始分化,各分支的分化时间则在更新世。祖先分布区重建研究表明黑藻最可能起源于东亚随后向东南亚、南亚、欧洲、大洋洲等其他地区扩散。仅在中国发现有四个分支的单倍型,并结合前人在其他国家和地区的研究表明中国很可能是黑藻的遗传多样性中心。4)测量中国黑藻样品的形态特征并结合其他地区黑藻样品的形态学数据,按照上述遗传证据(叶绿体基因证据和核基因数据)进行分组,研究黑藻种内是否存在分化。统计分析了总共118个样品的形态学数据,发现不同遗传谱系的黑藻在每轮叶片数、叶片长度、叶片宽度和叶形等形态特征上分别具有显著差异(P0.05),表明黑藻中可能存在种内分化。综上所述：黑藻在中国广泛分布于东北、华北、华中、华东、华南和西南地区。黑藻具有高的遗传多样性,但不同流域之间差异显著,呈现两头低中间高的趋势；黑藻在中国具有明显的谱系地理结构,南北分化明显；黑藻大约中新世后期在东亚分化随后向世界各地扩散,中国很可能是黑藻的遗传多样性中心；黑藻中可能存在新的分类。本研究揭示了水生植物广布种具有高的遗传多样性和显著的谱系地理结构,并作为首个水生植物广布种的生物地理研究案例,加深了我们对于水生植物进化的理解。
[Abstract]:Aquatic plants have different evolutionary processes with terrestrial plants because of their special habitats. There have been many studies using molecular genealogical geography to explore the evolution of aquatic plants, but rarely involve the wide variety of aquatic plants under large geographic scales. This study is based on the genus monophyla and has only a wide distribution of monophyll. The species of chloroplasts were collected in China to investigate their detailed geographical distribution; the genetic diversity and the geographic distribution pattern of the chloroplast in China were studied with chloroplast gene fragments and microsatellite loci, and the biogeographic history of the chloroplast was deduced from the broken sequence of chloroplast gene slices in other areas. Compared with the morphological data of different genetic branches in the species of the species, the main results are as follows: 1) the main results are as follows: 1) the chloroplast fragment was used to analyze the genetic diversity and genealogical structure of 123 species of the algae in this area. Hd=0.608 (Pi=0.0038) and genetic differentiation coefficient (Fsr=0.820), most of the genetic variation is derived from the population, only 17.97% of the genetic variation is derived from the population. The genetic diversity of the Yangtze River Basin and the southeast coastal basin is the highest, the Heilongjiang basin, the Liaohe River and the Haihe River Basin, the the Yellow River basin, and the the Yellow River basin. The genetic diversity is the lowest, and its genetic diversity is 0. in 681 individuals of 123 populations, which have 9 haplotypes. These haplotypes are clearly divided into 4 (A.B.C.D) and each of which has its own distribution range, indicating that the algae has a significant pedigree geographic structure (NsTGsT, P0.01).2) using the self-developed 5 pairs of microsatellite primers and literature. 3 pairs of microsatellite primers on the genetic diversity and genetic structure of monacotes were further studied. A total of 834 individuals were selected from 57 populations throughout the distribution area. At the same time, some chloroplast data in the previous chapter were also combined. It was found that there were 66 genotypes of the algae and 22 species were composed of single genotypes, indicating that the algae were asexual reproduction. The Clone Diversity index (D) was 0.269 (0 to 0.764). The genetic differentiation coefficient GsT was 0.2853. molecular variance analysis. The genetic difference between population and population was similar. 52% and 48%. genetic structure analysis of all genetic differences revealed that the population of black algae could be divided into two genetic groups according to their geographical distribution: the Southern Group (south of the Yangtze River) ) and the northern group (mainly in the north of the Yangtze River), corresponding to the A branch of the chloroplast gene +B and the C branch +D branches respectively. The two molecular markers all reveal that the genetic distance between the populations is positively correlated with the geographical distance but is unrelated in their respective genetic groups, indicating that the limited.3 of the gene exchange among the two large genetic groups is combined with the trnL-F sequence in other regions. 14 haplotypes were divided into four branches of A, B, C and D on the phylogenetic tree. According to the fossil calibration points, the algae began to differentiate at the late Miocene (6.71 Ma), and the differentiation time of each branch was in the Pleistocene. Spread to other regions such as Southeast Asia, South Asia, Europe and Oceania. Only in China have found four haplotypes, combined with previous studies in other countries and regions that suggest that China is likely to be the genetic diversity center of the black algae.4) to measure the morphological characteristics of the samples of the Chinese black algae and to combine the morphological data of the samples of other areas. According to the above genetic evidence (chloroplast genetic evidence and nuclear gene data), the differentiation of the species in the species was studied. The morphological data of 118 samples were statistically analyzed. It was found that there were significant differences in leaf number, leaf length, leaf width and leaf shape of different genetic lineages (P0 .05) indicates that there may be intraspecific differentiation in the algae. In summary, the black algae are widely distributed in Northeast China, North China, central China, East China, Southern China and southwest China. The algae have high genetic diversity, but the differences between different basins are significant, showing a trend of low middle height in two heads, and the black algae have a distinct genealogical structure in China and the north and the south. The differentiation is obvious; the diatom differentiation in the late Miocene in the late Miocene spread to all parts of the world, and China is likely to be the center of genetic diversity of the black algae, and there may be a new taxonomy in the black algae. This study reveals that the wide variety of aquatic plants has high genetic diversity and significant spectral geographic structure, and is the first aquatic plant to be widely used as the first aquatic plant. The biogeography study of species distribution has deepened our understanding of the evolution of aquatic plants.
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：Q949.2

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