基于mtCoI基因序列分析秦岭地区耶屁步甲(鞘翅目:步甲科)的谱系地理结构

为揭示秦岭地区耶屁步甲(Pheropsophus jessoensis Morawitz)种群的谱系地理结构,对秦岭2个地理区内25个耶屁步甲地理种群的184个个体的线粒体细胞色素氧化酶亚基Ⅰ (mtCoI)基因部分序列进行了分析.在879 bp个碱基中,共检测到55个变异位点,定义了67个单倍型.单倍型多样性(Hd=0.9550)较高,核苷酸多样性(Pi=0.0049)较低.东、西秦岭地区间和25个地理种群间的平均Kimura 2-parameter (K2P)遗传距离都很小,介于0.0026 ～0.0072.分子变异(AMOVA)和嵌套进化枝谱系地理学分析(NCPA)表明,耶屁步甲的分子变异主要来源于种群内个体间,而东、西两个地区间没有明显的谱系地理结构.错配分布和中性检验分析表明,单倍型之间存在一定的地理关联,距离隔离的限制性基因流以及快速或持续的种群扩张是造成该种目前遗传特征的主要因素.对秦岭地区的耶屁步甲进行种群动态推断,最近一次扩张时间发生0.05 ～ 0.23 Ma,处于更新世晚期,认为可能是第四纪冰期气候的反复变化导致了耶屁步甲现今的遗传格局.     

秦岭细鳞鲑群体遗传结构

秦岭细鳞鲑(Brachymystax lenok tsinlingensis)是秦岭地区特有鱼类,近年来由于环境恶化及人类活动的加剧,已对其造成严重影响,种群处于濒危状态,因此研究秦岭细鳞鲑的群体遗传结构、演化历史、分布动态等对其进行有效保护具有重要意义。本研究用线粒体D-loop区序列对秦岭地区6个群体(n=112)进行了遗传结构和群体演化分析。D-loop区扩增出的891bp序列在112个个体中,检测到42个变异位点,共26个单倍型;碱基序列总的单倍型多样度较高为0.883,核苷酸多样度为0.00799。AMOVA分析显示,60.05%的分子差异位于群体内,39.95%的分子差异位于群体间,Fst值统计检验表明,除那布大河群体与漳河群体和千河群体之间差异不显著之外,其余两两群体之间Fst值统计检验均为显著。系统树和单倍型网络图分析表明,6个地理群体的单倍型按照渭河上游和渭河中游两个河段形成两个大的类群,且5个群体共享一个单倍型H2,表明这些群体具有相同的演化历史,为同一个祖先群体演化而来。中性检验和歧点分布显示,秦岭细鳞鲑种群大小保持相对稳定,未经历明显的种群扩张。同时建议将渭河上游秦岭细鳞鲑群体作为一个整体进行重点保护。     

淮河野生鲇鱼线粒体Cyt b基因的序列变异与遗传结构分析

本研究利用线粒体DNA细胞色素b(Cyt b)基因序列分析淮河信阳段、淮滨段、蚌埠段、洪泽湖及其支流颍河、淠河和池河的野生鲇鱼(Silurus asotus)种群遗传结构及种群历史.结果表明,在841 bp的同源序列中,7个种群共检测到变异位点40个,占全部序列的4.76％,121个个体共检测到32种单倍型;7个种群的平均单倍型多样性(h)、核甘酸多样性(Pi)分别为0.884 8、0.003 8,表明淮河野生鲇鱼种群的遗传多样性水平较高.7个种群间的遗传分化指数Fst为0.115 0,仅12.92％的变异来自种群间(AMOVA分析),基因交流值为3.85,种群间K2-P遗传距离为0.002 ～0.009,显示鲇鱼种群间没有发生明显的地理分化.NJ树揭示7个种群的个体组成2个谱系,但这2个谱系与地理分布并不相关.中性检验、错配分析和Network网络亲缘关系分析皆表明鲇鱼种群有过种群扩张,扩张时间约在0.17～0.29百万年前的中更新世中期和末期.     

基于线粒体Cyt b序列对新疆额尔齐斯河贝加尔雅罗鱼遗传结构的分析

采用线粒体Cyt b基因序列对额尔齐斯河流域的青河(QH,18尾)、哈巴河(HBH,21尾)、185团(185T,18尾)和乌伦古湖(WLG,20尾)4个贝加尔雅罗鱼(Leuciscus leuciscus baicalensis)群体进行了遗传结构的比较分析。在片段长度为1 109 bp的同源序列上,77尾个体共检测到54种单倍型,其中共享单倍型7个,总单倍型多样性指数(Hd)、总核苷酸多样性指数(π)和平均核苷酸差异数(K)分别为0.981 9、0.008 21和9.091,且185团群体单倍型多样性指数和核苷酸多样性指数最高、青河群体最低。4个群体间遗传距离在0.006~0.011之间,基于Kimura 2-parameter法构建的单倍型邻接关系树分为3支,群体间遗传关系和地理分布没有明显的相关性。AMOVA分析显示额尔齐斯河流域贝加尔雅罗鱼遗传差异极显著(P0.01)。青河和乌伦古湖群体基因流(Nm)远高于其他群体间,推测乌伦古河或许是二者进行基因交流的渠道。尽管单倍型核苷酸不配对分布呈双峰,但偏差平方和(Q)与粗糙指数(r)均不显著(P0.05),且Tajima′s D和Fu′s Fs检验也均显著偏离中性,结合群体呈现高单倍型多样性和低核苷酸多样性的特点,推测贝加尔雅罗鱼经历了群体扩张事件。参考已校正的鲤科鱼类Cyt b基因0.76%/Ma的进化速率,估算群体扩张的时间大约在1.97 Ma前的更新世中晚期,推测该时期阿尔泰山地区发生的冰川作用和频繁的古地震造成的地理隔离和融合可能是贝加尔雅罗鱼发生群体扩张的重要原因。     

基于线粒体DNA的中国亚洲象种群遗传多样性及种群遗传结构

亚洲象是我国国家一级保护动物.本文利用非损伤性取样法,以亚洲象粪便中脱落的肠道上皮细胞为DNA来源,选用线粒体DNA作为分子标记,对分布于我国境内的亚洲象种群的遗传结构和种群遗传多样性进行研究.本研究得到mtDNA序列片段长度为556 bp,经对178个个体进行扩增结果分析,共得到24个单倍型.在5个地理种群中,除南滚河种群外,其他4个种群中的114个个体共享同一单倍型,南滚河种群与其他种群间未观察到共享单倍型.系统发生分析,观察到中国境内现有亚洲象种群在进化上分为两大分支,α和β.其中分支α中包含除南滚河种群外的4个地理种群,分支β仅含有南滚河种群,表明南滚河种群与其他4个地理种群间存在明显分化.遗传多样性分析结果表明,中国境内的亚洲象种群的遗传多样性水平较低,分析原因认为是栖息地破碎化阻断了种群间有效的基因交流.     

秦岭地区赤胸梳爪步甲种群的遗传多样性和扩张历史分析（英文）

赤胸梳爪步Dolichus halensis (Schaller)（鞘翅目：步甲科）是重要的捕食性天敌昆虫,在我国分布广泛。为揭示其种群遗传多样性和扩张机制, 本研究以秦岭地区为中心,以线粒体Cox1 tRNALeu Cox2基因片段为分子标记,对来自于24个采集点共191个个体进行了检测分析。在长度为1 601 bp的碱基中共检测到45个变异位点,定义了53个单倍型,单倍型多样性高（H_d=0.796）,而核苷酸多样性较低（P_i=0.0033）。系统发育分析结果表明该地区该物种存在两大进化枝。分子变异分析（AMOVA）表明86.61%的变异来源于种群内。SAMOVA和PERMUT分析结果一致,表明秦岭地区分布的赤胸梳爪步甲种群不存在明显的谱系地理结构。中性检验和错配分布分析的结果一致,表明该物种在秦岭地区曾经发生过种群扩张。综上,认为赤胸疏爪步甲种群经历过冰期后的扩散。     

基于线粒体DNA控制区的石鸡华北亚种的种群历史动态研究

隶属于鸟纲鸡形目雉科的石鸡是一个多型种,在我国已有7个亚种被报道,其中石鸡华北亚种是我国的特有鸟。用石鸡华北亚种(Alectoris chukar pubescens)12个地理种群112个样本的线粒体DNA控制区(mt DNA CR)1154 bp序列的信息研究了石鸡华北亚种的种群历史动态。112个样本中共发现28个变异位点,定义了29种单倍型,其中12个地理种群的50个样本共享单倍型H1,8个地理种群的16个样本共享单倍型H4。地理种群间存在较大的基因流,且种群间没有由于地理距离产生隔离的证据。负的Tajima(D=-1.336,P0.05)和Fu(Fs=-1.720,P0.05)统计检验值及错配分布的单峰模式都支持石鸡华北亚种经历了种群扩张。石鸡华北亚种大部分种群的错配分布与种群过去的扩张相一致,扩张发生在晚更新世中期的第五寒冷期(0.027—0.06 Ma)。推测其扩张的原因可能为:1)更新世期间我国北方地区没有发生大规模的冰川,2)青藏高原的隆升使我国北方干旱化和荒漠化加剧利于石鸡种群的扩散。武都(WD)位于东洋界,而石鸡是典型的古北界的鸟种,表明WD种群可能是石鸡在东洋界的一个建群种,因此需要给予充分的关注。     

线粒体DNA多态性在海洋动物群体遗传结构研究中的应用

线粒体DNA( mtDNA)分析在揭示物种亲缘关系、遗传比较、系统进化和遗传结构等领域的研究中得到了广泛的应用,尤其是在海洋动物的遗传结构研究中发挥了重要的作用.介绍线粒体DNA的结构特征、多态性研究方法,并对其在海洋动物群体遗传结构研究中的应用进行了综述.     

基于线粒体DNA D-loop区部分序列分析舟山海域带鱼种群遗传结构

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基于线粒体控制区的嘉陵裸裂尻鱼种群遗传结构分析

嘉陵裸裂尻鱼为青藏高原特有鱼类,近年来随自然地理气候的变迁和人类活动的影响,种群数量急剧减少。为了解嘉陵裸裂尻鱼的遗传背景以便更好的保护其遗传资源,本研究采用线粒体控制区部分序列变异,分析了嘉陵裸裂尻鱼6个地理种群的遗传结构和分布动态。在147尾个体中共发现17个变异位点,定义了14种单倍型,群体总的单倍型多样性较高为0.810,核苷酸多样性低为0.00698。AMOVA分析显示,44.29%的分子差异源于群体间,55.71%的分子差异源于群体内,群体间遗传分化极显著。Fst值统计检验表明,除宕昌群体和舟曲群体之间差异不显著外,其余两两群体之间Fst值统计检验均显著。基因流估计显示各群体间的基因流水平较高,遗传交流较频繁。Mantel test检验表明,嘉陵裸裂尻鱼种群之间遗传分化程度与地理距离存在显著相关。系统树和单倍型网络进化图显示,6个地理群体的单倍型按照嘉陵江水系和渭河水系形成两个大的类群。错配分布和中性检验表明嘉陵裸裂尻鱼群体在近期历史上群体大小保持稳定,未出现显著的种群扩张。根据本文所揭示的嘉陵裸裂尻鱼种群遗传结构特征,建议将分布在嘉陵江水系的嘉陵裸裂尻鱼作为一个整体进行保护,嘉陵裸裂尻鱼渭河种群属高度分化的单倍型类群,且遗传多样性极低,需对该种群进行优先保护。     

Population genetic structure and historical demography of the ground beetle Pheropsophus jessoensis from the Tsinling-Dabashan Mountains, central China based on mitochondrial DNA analysis

The population genetic structure and demographic history of the ground beetle Pheropsophus jessoensis (Coleoptera: Carabidae) from the Tsinling-Dabashan Mountains, central China were estimated using the mtDNACol-tRNALeu-mtDNAColl region as a molecular marker. 184 individuals from 25 local populations, were collected. The haplotype diversity (H(d)) of total and each individual sampled population was high, and was accompanied by lower nucleotide diversity (P(i)). AMOVA analysis suggested that most of the variation was within populations (92.17%), while differentiation of among populations only contributed 7.83% to the total. Mantel test results showed significant correlation between the pairwise calculated genetic distance and pairwise calculated geographical distance of the populations (R(xy) = 0.360529, P = 0.00001 < 0.01), indicating the presence of isolationby-distance. No phylogeographic structure was found within the Tsinling-Dabashan Mountains region. Statistical phylogeographic analysis indicated that the contemporary populations are derived from multiple ancestral-refugial source populations. Gene flow calculated through the N(m) was high between many pairs of populations, which was probably due to ancient vicariance and subsequent rapid expansion of populations. The results of neutral test, mismatch distribution analyses, and Bayesian Skyline Plot (BSP) analysis together indicated a sudden demographic expansion. The estimated expansion time of individual haplogroup and the whole sampled population were 0.012-0.278 Myr, and a sudden expansion was identified between 0.05 Myr to 0.01 Myr by BSP. The postglacial population expansion might lead to the lack of phylogeographic structure.     

Population genetic structure of striped mullet, Mugil cephalus, along the coast of China, inferred by AFLP fingerprinting

The striped mullet, Mugil cephalus, is an economically important species for both aquaculture and commercial fisheries in China. In this study, the amplified fragment length polymorphism (AFLP) technique was employed to analyze population genetic diversity and genetic distance between different populations with the aim of elucidating the population structure and gene flow of M. cephalus along the coast of China. A total of 230 fragments with 150–500 bp were identified from 118 individuals by five AFLP primer combinations. The polymorphic loci within populations varied from 46.52% to 64.78%, with an average of 53.91%, and the average heterozygosity from 0.1829 to 0.2282, with an average of 0.2074. The UPGMA phenograms of 118 individuals were constructed based on Dice similarity coefficients and four clusters were recognized. AMOVA analysis revealed that 60.7% of genetic variations were within populations and 39.3% between populations. The estimated genetic distance (φ_ST) value over all polymorphic loci across the six populations was 0.393 (p < 0.0010), indicating a strong population structuring. The pairwise φ_ST value ranged from 0.1112 to 0.5358, with an average of 0.3693. The population pairwise gene flows (average N_m = 0.73) are low. In addition, the result of the Mantel test showed that there was a significant correlation between geographic and genetic distances (r = 0.5434, p = 0.0050). It was speculated that there exist at least four distinct geographic populational subdivisions of M. cephalus along the Chinese coast. This research has provided new molecular data which will aid our understanding of the genetic structure of this species.     

基于线粒体COI基因分析钩手水母的群体遗传结构

钩手水母(Gonionemus vertens)为大西洋和太平洋广布种, 是我国习见的有毒水母种类之一。本文对采自黄渤海海域4个地理群体的104个钩手水母线粒体COI基因序列进行扩增, 并结合GenBank上其他182个钩手水母同源序列进行序列变异分析。在286个基因序列中共检测出52个多态位点, 定义了14种单倍型。总群体的单倍型多样性和核苷酸多样性分别为0.743 ± 0.012和1.046% ± 0.097%, 与其他几种大型水母相比, 钩手水母总群体的遗传多样性处于较高水平。AMOVA结果显示, 60.17%的分子变异源于群组间, 13.37%的分子变异源于群体内, 26.46%的分子变异源于组内群体间, 群组间、群体内和组内群体间的遗传分化均极显著。F_st值统计检验表明, 中国厦门群体与乐亭、东营、烟台、大连群体间存在显著的遗传分化, 大连与东营、烟台群体间也存在显著的遗传分化。系统分析结果显示, 钩手水母群体间存在2个明显的单倍型谱系分支。不同的钩手水母地理群体间具有复杂的遗传模式, 钩手水母复杂的生活史、扩散能力、地理隔离和海流分布可能是影响钩手水母遗传结构的重要因素。     

燕山山脉软枣猕猴桃的居群结构与动态研究

为探究层间藤本植物软枣猕猴桃（Actinidia arguta）在群落中的生长格局和居群动态变化,以燕山区域内的野生软枣猕猴桃为研究对象,采用样圆法分区域进行了野生软枣猕猴桃的居群结构调查,编制了特定时间生命表并绘制存活曲线。结果表明：燕山区域Ⅰ-Ⅱ径级（幼苗阶段）种群个体分别占总数量的15.39%（东段）、31.25%（中段）和30.76%（西段）,总体居群结构呈"倒金字塔"型,种群表现出衰退趋势。调查区域软枣猕猴桃的高度结构基本符合连续发育特征,相对完整。燕山东段和中段的软枣猕猴桃较明显地趋近Deevey-Ⅱ型指数函数模型,燕山西段介于Deevey Ⅰ型与Ⅱ型之间,但更接近Ⅱ型;燕山山脉软枣猕猴桃居群整体呈现衰退型特征。软枣猕猴桃有较高的保护价值,但其居群数量稀少,自然更新能力较弱,种群未来的生长繁衍不容乐观,应加强关注与保护力度。     

An AFLP analysis of genetic diversity and structure of Caragana microphylla populations in Inner Mongolia steppe, China

Genetic diversity and structure of five natural populations of Caragana microphylla from the Inner Mongolia steppe were estimated using AFLP markers. Five pairs of primers generated a total of 312 bands among 90 individuals, with percentage of polymorphic bands (PPB) being 63% at the population level and 76% at the species level, respectively. The genetic diversity within populations was correlated significantly with the soil N:P ratio. AMOVA analysis revealed high genetic variations within populations (95.5%). The estimated number of migrants per generation (Nm) was 10.72, indicating a high level of gene flow among populations. There was no significant correlation (r = 0.36) between genetic distance and geographical distance. These results were discussed in terms of eco-geographical variations among populations, together with the life history traits and breeding system of the species. The knowledge obtained may have important implications for better conservation and wise use of the vegetation dominate by C. microphylla.