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1.
该研究基于ITS1-ITS4序列对濒危植物长柄扁桃(Amygdalus pedunculata)自然分布区内的8个居群,105个个体的遗传多样性及遗传结构进行了分析,以明确长柄扁桃的地理分布及其遗传多样性特征。结果表明:(1)ITS1-ITS4序列长度583bp,变异位点13个,共定义了8个单倍型;居群间总的遗传多样性(hT)为0.727,居群内平均遗传多样性(hS)为0.564,各居群单倍型多样性、核酸多样性的变化范围分别为0.182~0.636、0.000 6~0.006 3。(2)AMOVA分析表明,33.65%的遗传变异来自居群间,而66.35%的遗传变异来自居群内;居群间平均基因流(Nm)为0.986,居群间遗传分化系数NSTGST(GST=0.225,NST=0.362,P0.05),表明长柄扁桃居群间存在不十分显著的遗传分化,但谱系地理结构显著;中性检验和错配分布曲线表明,居群自然分布区内的长柄扁桃没有经历明显的近期扩张。(3)单倍型网络和最大似然树都表明:内蒙古和陕西的长柄扁桃居群分别聚为2个明显的分支。  相似文献   

2.
本研究对分布在中国新疆维吾尔自治区阿尔金山自然保护区的6个真藓(Bryum argenteum)居群的遗传结构及遗传多样性进行比较。通过对32条叶绿体DNA的rpl32-trnL序列的核苷酸序列变异的分析,发现了14种单倍型,存在201个可变位点;分子变异分析显示有51.02%的遗传变异发生在居群间水平,居群内部的遗传变异为48.98%,真藓居群间的遗传分化程度较高略大于居群内的遗传分化。居群遗传变异的分化系数为0.510 2,基因流值为0.48,显示各居群间的基因流低。单倍型多态性水平为(0.780 2±0.076 0),核苷酸多态性水平为(0.058 59±0.020 09),表明真藓居群遗传多样性丰富。对所有变异位点进行的Taijma's检验的结果是Taijma's D值为-1.567 05 (p0.10),显示所有变异符合中性进化假说。  相似文献   

3.
采用叶绿体DNA非编码区直接测序的方法,对青海、甘肃、四川3个省区内濒危植物宽叶羌活14个天然居群的遗传多样性和遗传结构进行了研究,以明确其遗传背景,为宽叶羌活的保护提供理论依据。结果表明:(1)14个居群138个个体的序列长度介于509~515bp;碱基组成A+T含量较高(平均67.6%)。(2)根据序列的核苷酸变异共鉴定出31个单倍型,其中9种单倍型(H5、H1、H9、H10、H16、H17、H19、H20、H22)为居群所共享,而且单倍型H5分布最广、在10个群体的67个个体中检测到,占总样品数的48.56%。(3)14个居群宽叶羌活具有高水平单倍型多样性(Hd=0.750 3)和较高水平核苷酸多样性(Pi=0.007 11),但31个单倍型没有按地理分布形成明显的族群,各地理单元中的单倍型相互混杂,没有明显的地理分化模式。(4)AMOVA分析、居群间分化度(FST=0.602 4)分析和基因流(Nm=0.330)分析的结果一致,表明宽叶羌活大部分遗传变异(60.24%)发生在居群间,居群间的基因流较低,群体间变异是宽叶羌活的主要变异来源。(5)14个居群的遗传距离在0.000~0.007,平均为0.003,表明居群间的亲缘关系较远,且居群间的遗传距离与地理距离之间无显著相关关系(P=0.143),说明宽叶羌活居群遗传变异的分布没有明显的地理趋势。研究认为,宽叶羌活居群间高的遗传变异可能是由基因流受阻、遗传漂变、地理隔离造成的,并提出了对该物种遗传多样性的保护策略。  相似文献   

4.
喜马拉雅旱獭是青藏高原的优势种,数量多、分布广,全面了解其遗传背景对该地区旱獭资源的保护与合理利用具有重要的意义。本研究以青藏高原云南、西藏和青海三省区共13个地理种群计258只旱獭为研究对象,PCR扩增获得线粒体DNA控制区基因部分序列(887 bp),并运用种群遗传学方法进行遗传多样性分析。结果显示:258份样品共发现了84个变异位点(9.40%),定义了68种单倍型,其单倍型多样性(h)平均值为0.968±0.003、核苷酸多样性(π)平均值为0.017 25±0.016 37,种群总体遗传多样性较高。AMOVA方差分析显示13个地理种群间存在着明显的遗传分化(Fst=0.620 67,P<0.001),种群间基因交流多数较低(Nm<1)。基于单倍型构建的系统发育树中13个地理种群的喜马拉雅旱獭聚为两支,其中来自青藏高原西南地区(西藏安多、青海格尔木、青海囊谦、云南迪庆)的18个单倍型聚成一个大的分支(A支),其余50个单倍型聚为一个大的分支(B支),在NETWORK网络图中也可见到相似网络拓扑结构。研究结果显示青藏高原喜马拉雅旱獭种群以唐古拉山脉为界分为两个大的种群,说明地理隔离是影响喜马拉雅旱獭种群动态变化的主要因素。  相似文献   

5.
应用ISSR分子标记技术,对云南南部7个地区的野生大叶千斤拔( Flemingia macrophylla)居群进行了遗传多样性分析。结果表明:云南野生大叶千斤拔具有较高的遗传多样性。在物种水平上,平均每个位点的多态位点百分率(PPL)为94.85%,有效等位基因数(Ne)为1.4627,Nei’s基因多样性指数(He)为0.2815, Shannon’s多样性信息指数(Ho)为0.4337;在居群水平上,PPL =43.44%,Ne =1.2981,He =0.1704,Ho =0.2499。基于Nei’ s遗传多样性分析可得出,居群间的遗传分化系数( Gst)为0.3975,表明居群内的遗传变异为60.25%,居群间的遗传变异为39.75%,这说明居群间的遗传分化要低于居群内的遗传分化。根据遗传多样性分析和聚类结果,应在大叶千金拔遗传多样性较高的勐腊易武( MY)、丘北( QB)和宁洱( NE)地区,设立保护点对其进行就地保护。  相似文献   

6.
云南虫生真菌粉棒束孢遗传分化研究   总被引:3,自引:2,他引:1  
对云南粉棒束孢8个当地居群和蝙蝠蛾拟青霉2个当地居群进行ITS测序和RAPD扩增分析,结合Gen Bank中相关序列,对粉棒束孢开展遗传多样性、居群遗传结构及其种内分化研究。共获得大范围内地理距离远的6个居群共97条粉棒束孢ITS序列,共有33种单倍型,单倍型多样性Hd=0.546和总核苷酸多样性Pi=0.00276,显示粉棒束孢在物种水平上遗传多样性较低。云南粉棒束孢共37条序列,有14种单倍型(10种为云南特有),具有较高单倍型多样性和核苷酸多样性(Hd=0.659,Pi=0.00274);单倍型聚类和网状分支分析表明云南粉棒束孢单倍型类型丰富,遗传多样性高,暗示云南为粉棒束孢多样性分布中心之一。ITS序列分析表明,云南当地居群间遗传分化系数Fst=51.95%;RAPD分析表明,居群间遗传分化系数Gst=0.5547,基因流Nm=0.4014;说明云南当地居群粉棒束孢分化剧烈。居群遗传距离与地理距离相关性研究表明,粉棒束孢居群遗传距离与地理距离无明显相关。中性检验和失配分析表明粉棒束孢经历过近期居群扩张。结合单倍型聚类和网状分支分析,表明Hap 19为扩张建群单倍型,但原始祖先单倍型(Hap 1)依然是粉棒束孢居群中最优势单倍型(频率为48.45%),表明粉棒束孢并不存在明显的因地理原因造成的生殖隔离。值得重视的是,通过ITS单倍型和RAPD分析,支持将蝙蝠蛾拟青霉作为粉棒束孢异名处理。  相似文献   

7.
用SSR方法对云南元江普通野生稻3个自然居群进行30个位点的遗传多样性分析.结果表明,元江普通野生稻具有较高的遗传变异水平(Ap=2.6,Hs=0.77),且群体遗传分化系数较大,GST为41.08%,即在遗传变异总量中41.08%存在于居群间.本文还通过对云南元江普通野生稻遗传多样性特点的分析,提出了保护策略.  相似文献   

8.
大百合是百合科大百合属一种重要的野生植物资源,本研究采用基因测序法,利用叶绿体DNA rpl16序列对10个大百合居群进行了遗传多样性和遗传结构分析,旨在为其资源保护和开发利用提供理论基础。结果显示:rpl16序列矩阵长度为699 bp,共检测到14个变异位点和12个单倍型,单倍型多态性(Hd)为0.604;总的遗传多样性(HT)为0.660。该居群间遗传变异(71.53%)大于居群内遗传变异(28.47%),说明居群间变异是其居群的主要变异来源;居群间遗传分化很高(Gst=0.677,Nst=0.614,Fst=0.71531),基因流较低(Nm=0.0995)。失配分析结果表明种群在进化过程中曾经历过快速扩张,中性检验支持上述结果:Tajima′s D=-1.74368(P0.05);Fu and Li′s D=-2.69366(P0.05);Fu and Li′s F=-2.79896(P0.05)。研究结果表明:大百合居群遗传多样性较高,居群间存在较高的遗传分化,主要与其生活史特征相关。基于得到的居群遗传信息,建议采取就地保护为主的保护策略。  相似文献   

9.
利用叶绿体基因(rbcL和trnS-G)及核糖体DNA内转录间隔区(ITS),对祁连山区狭域分布的特有物种黑虎耳草8个居群(115个个体)进行遗传多样性研究,旨在揭示黑虎耳草的居群遗传结构及其历史进化过程。结果表明:(1)所有取样个体共检测到4个cpDNA单倍型和9个ITS单倍型,其中祁连山东南部的居群固定较多的单倍型和特有单倍型,而西北部居群只固定少数几个广泛分布的单倍型,且遗传多样性普遍较低。(2)基于cpDNA数据和ITS数据的分子变异分析(AMOVA)显示,遗传变异主要来源于居群内。(3)基于cpDNA数据的中性检验表明,Tajima’s D(-1.012 30,P 0.05)和FuLi’s D*(-2.066 77,P 0.05)均为负值,均不显著;歧点分布分析结果显示,黑虎耳草居群经历过近期的扩张事件。根据物种现有遗传分布格局推测,黑虎耳草在第四纪冰期时退缩到祁连山东南部的边缘避难所,间冰期或冰期后回迁到祁连山西北部地区,在回迁过程中由于奠基者效应导致祁连山西北部的居群仅固定少数广泛分布的单倍型,并呈现出较低的遗传多样性;由于居群较小且相互隔离,该物种经历了严重的瓶颈效应和遗传漂变,导致该物种总遗传多样性(H_T)和居群平均遗传多样性(H_S)远低于虎耳草属其他青藏高原-喜马拉雅广域分布的物种。  相似文献   

10.
基于叶绿体单倍型的山东丹参居群遗传结构分析   总被引:2,自引:1,他引:1  
依据叶绿体psbA-trnH基因间隔区的序列多态对来自山东地区丹参的3个自然居群和1个栽培居群进行了遗传结构研究.结果显示,80个供试材料中共有10种单倍型,核苷酸多样性为0.024,叶绿体DNA单倍型进化分支分析把10种单倍型分为2大支,但每支都由4个居群的单倍型共同构成;Nei多样性指数为0.284,Shannon信息指数为0.406,多态位点百分比率为70%;4个居群总基因多样性为0.905,居群内平均基因多样性指数为0.747,遗传分化系数为0.175;不同居群间的遗传分化系数为0.017~0.199,基因流为2.013~28.912;AMOVA分析揭示居群间只有5%的遗传差异.研究结果表明,山东丹参遗传多样性水平较高,但由于彼此较高的基因交流,居群间遗传分化水平低,仅有的遗传差异主要存在于居群内;另外,序列谱系关系分析表明山东栽培丹参来源复杂且具有丰富的遗传多样性.  相似文献   

11.
为揭示北沙柳(Salix psammophila)的遗传多样性、遗传结构及分化特征,利用叶绿体非编码区序列(trnL-trnF和trnD-trnT)对分布于毛乌素沙地和库布齐沙漠的16个北沙柳居群(339个个体)进行了遗传研究,为北沙柳种子资源库遗传管理、遗传改良、遗传育种及品种选育提供理论依据。结果表明:(1)经trnL-trnF和trnD-trnT片段联合比对获得了1811 bp序列,共有12个核苷酸变异位点(8个简约信息位点,4个变异位点),得到16个单倍型。(2)单倍型多样性指数(Hd)为0.737,核苷酸多样性指数(π)为0.00107;且单倍型H3的分布在所有居群中位于单倍型网络图中心,其余单倍型随机分布于各个居群。(3)AMOVA分析表明,北沙柳cpDNA的变异主要来源于居群内(91.16%),居群间遗传分化程度中等(FST=0.08837),各居群间的基因交流非常频繁(Nm=2.58);遗传分化系数NST(0.085)显著大于GST(0.056,0.01相似文献   

12.
ABSTRACT: BACKGROUND: As one of the most important but seriously endangered wild relatives of the cultivated tea, Camellia taliensis harbors valuable gene resources for tea tree improvement in the future. The knowledge of genetic variation and population structure may provide insights into evolutionary history and germplasm conservation of the species. RESULTS: Here, we sampled 21 natural populations from the species' range in China and performed the phylogeography of C. taliensis by using the nuclear PAL gene fragment and chloroplast rpl32-trnL intergenic spacer. Levels of haplotype diversity and nucleotide diversity detected at rpl32-trnL (h = 0.841; pi = 0.00314) were almost as high as at PAL (h = 0.836; pi = 0.00417). Significant chloroplast DNA population subdivision was detected (GST = 0.988; NST = 0.989), suggesting fairly high genetic differentiation and low levels of recurrent gene flow through seeds among populations. Nested clade phylogeographic analysis of chlorotypes suggests that population genetic structure in C. taliensis has been affected by habitat fragmentation in the past. However, the detection of a moderate nrDNA population subdivision (GST = 0.222; NST = 0.301) provided the evidence of efficient pollen-mediated gene flow among populations and significant phylogeographical structure (NST > GST; P < 0.01). The analysis of PAL haplotypes indicates that phylogeographical pattern of nrDNA haplotypes might be caused by restricted gene flow with isolation by distance, which was also supported by Mantel's test of nrDNA haplotypes (r = 0.234, P < 0.001). We found that chlorotype C1 was fixed in seven populations of Lancang River Region, implying that the Lancang River might have provided a corridor for the long-distance dispersal of the species. CONCLUSIONS: We found that C. taliensis showed fairly high genetic differentiation resulting from restricted gene flow and habitat fragmentation. This phylogeographical study gives us deep insights into population structure of the species and conservation strategies for germplasm sampling and developing in situ conservation of natural populations.  相似文献   

13.
江孜沙棘和云南沙棘之间谱系分化和亲缘地理   总被引:3,自引:0,他引:3       下载免费PDF全文
研究具有邻近分布的近缘类群的遗传分化和谱系筛选对于进一步揭示物种形成机制具有重要意义。该文以沙棘属(Hippophae)临域分布的两个类群, 江孜沙棘(H. gyantsensis)和云南沙棘(H. rhamnoides subsp. yunnanensis)为研究对象, 进行群体水平上的母系分化研究。前一个种分布于西藏的中西部, 而后者主要分布于青藏高原东南部的云南西北部、四川西部和西藏东南部。两个类群在叶和果实性状存在明显区别。叶绿体在沙棘属植物中为母系遗传。共研究了两个类群14种群109个沙棘个体的叶绿体trnL-F、trnS-G序列; 序列排序后共发现11种单倍型, 江孜沙棘和云南沙棘分别有7种和6种, 两种单倍型为两个类群共享。分支分析和嵌套进化分析进一步表明, 两个类群之间的单倍型相互交错, 单倍型分化与形态上划分的两个类群不一致, 表明它们之间具有十分复杂的谱系筛选过程。这些发现明显不支持以前提出的有关江孜沙棘系统位置的假设。但是, 目前所获得的证据不能区分该物种究竟是通过异域分化还是同倍性杂交起源的。不同种群固定特有单倍型表明, 两个类群都在最后一次冰期可能存在多个避难所。  相似文献   

14.
潘跃芝  赵玉娟  龚洵 《广西植物》2021,41(3):340-350
异叶泽兰属于菊科泽兰属,是该属分布海拔相对较高的植物,分布在青藏高原东部和横断山海拔1700~3000 m的地区。该文利用ycf6-psbM和rpl32-trnL两个叶绿体DNA(cpDNA)片段以及核DNA片段ITS(nITS)作为分子标记,研究了异叶泽兰的遗传多样性及其分布特征,探讨了其居群历史动态。结果表明:(1)叶绿体片段联合分析结果显示,异叶泽兰在物种水平遗传多样性水平不高,单倍型多态性指数(Hd)为0.656,核苷酸多态性(π)为0.00161;而ITS的基因型多态性指数(H d)为0.687,核苷酸多态性(π)为0.00235。(2)cpDNA和nITS分析结果均显示,异叶泽兰居群水平总的遗传多样性大于居群内平均遗传多样性,遗传变异主要发生在居群间,居群间存在明显的遗传分化(cpDNA:Gst=0.679,Nst=0.655,F st=0.655;nITS:Gst=0.543,Nst=0.370,Fst=0.584),但是由于Nst值小于Gst值,因此异叶泽兰的分布不具有明显的谱系地理结构。(3)基于单倍型地理分布以及Network分析推测,横断山区南部(川西南-滇西北)和云南中部可能是异叶泽兰在第四纪冰期时的两个避难所,中性检验和失配分析的结果支持异叶泽兰在冰期后未发生过居群扩张。  相似文献   

15.
To investigate the genetic diversity between the populations of woolly flying squirrels (Eupetaurus) from the eastern and western extremes of the Himalayas, partial mitochondrial cytochrome b gene sequences (390-810 bp) that were determined from the museum specimens were analyzed using maximum parsimony (MP) and maximum likelihood (ML) methods. The molecular data reveal that the two specimens that were collected in northwestern Yunnan (China) are members of the genus Eupetaurus. Reconstructed phylogenetic relationships show that the populations of Eupetaurus in the eastern and western extremes of the Himalayas are two distinct species with significant genetic differences (12%) and diverged about 10.8 million years ago. Eupetaurus is significantly different from Petaurista and Pteromys. The level of estimated pairwise-sequence divergence observed between Eupetaurus and Petaurista or Pteromys is greater than that observed between Eupetaurus and Trogopterus, Belomys, Glaucomys, or Hylopetes. Considering the divergence time of the two Eupetaurus groups, the glaciations and the uplift of the Himalayas and Qinghai-Tibet plateau during the Pliocene-Pleistocene period might be the major factors affecting the present distribution of Eupetaurus along the Himalayas.  相似文献   

16.
赵小丽  杨耀文  李国栋 《广西植物》2021,41(12):2004-2013
为了探索草果(Amomum tsaoko)的栽培地理起源,该文检测了草果、拟草果(A. paratsaoko)的cpDNA序列变化,并获取了单倍型多态性信息。结果表明:(1)20个草果居群272个植株、5个拟草果居群62个植株共检测到7种单倍型。其中,草果有3种单倍型(H1、H3、H6),拟草果有6种单倍型(H1、H2、H3、H4、H5、H7)。H1和H3为共享单倍型,H6为草果私有单倍型,H2、H4、H5、H7为拟草果私有单倍型。H1为普通单倍型,H2为祖先单倍型。(2)草果居群遗传多样性远小于拟草果居群,遗传变异主要来源于居群内,拟草果居群主要来源于居群间。麻栗坡铁厂(TC)、屏边玉屏(YP)居群的遗传多样性、单倍型多样性高于其他18个草果居群。(3)进一步分析表明,包含屏边、马关、西畴、麻栗坡的云南东南部前端地域和邻接的广西那坡可能共同构成草果栽培驯化起源中心,以麻栗坡为核心区域,向周边的西畴、马关、屏边、那坡扩张。因此,结果显示应对TC、YP、那坡下华(XH)居群加以保护。该研究结果为草果种质资源保护、利用提供了遗传学信息。  相似文献   

17.
Range-wide genetic variation of the widespread cold-temperate spruce Picea jezoensis was studied throughout northeast Asia using maternally inherited mitochondrial DNA and paternally inherited chloroplast DNA markers. This study assessed 33 natural populations including three varieties of the species in Japan, Russia, China, and South Korea. We depicted sharp suture zones in straits around Japan in the geographical distribution pattern of mitochondrial haplotypes (GST=0.901; NST=0.934). In contrast, we detected possible extensive pollen flow without seed flow across the straits around Japan during the past population history in the distribution pattern of chloroplast haplotypes (GST=0.233; NST=0.333). The analysis of isolation by distance of the species implied that by acting as a barrier for the movement of seeds and pollen, the sharp suture zones contributed considerably to the level of genetic differentiation between populations. Constructed networks of mitochondrial haplotypes allowed inference of the phylogeographical history of the species. We deduced that the disjunction with Kamchatka populations reflects range expansion and contraction to the north of the current distribution. Within Japan, we detected phylogeographically different types of P. jezoensis between Hokkaido and Honshu islands; P. jezoensis in Honshu Island may have colonized this region from the Asian continent via the Korean peninsula and the species in Hokkaido Island is likely to have spread from the Asian continent via Sakhalin through land bridges. Japanese endemism of mitochondrial haplotypes in Hokkaido and Honshu islands might have been promoted by separation of these islands from each other and from the Asian continent by the straits during the late Quaternary.  相似文献   

18.
In the present study, we used two chloroplast DNA (cpDNA) fragments (trnL-F and rps16) and the nuclear ribosomal internal transcribed spacer (ITS) sequence data to examine intraspecific differentiation and phylogeographical history of Allium wallichii. Based on wide scale sampling (28 populations and 174 individuals) across the entire distribution range of this species, 33 cpDNA haplotypes and 25 ITS ribotypes were detected in our investigation. These cpDNA haplotypes were divided into three major lineages, which was further supported by the ITS phylogenetic results. High haplotype/ribotype diversity and population differentiation, together with most of the haplotypes/ribotypes being exclusive to single populations, implied restricted gene flow among populations and significant geographical isolation. Nearly all populations with high haplotype/ribotype diversity were found in the Hengduan Mountain Region (HMR), whereas the populations of the Himalayas and Nanling Mountains showed a lower level, suggesting the HMR might serve as a potential divergence center for A. wallichii. The main lineages of A. wallichii diverged from each other between Mid–Late Pliocene and Early Quaternary based on two sets of molecular markers, indicating that the Quaternary climatic fluctuation could not have contributed greatly to the divergence of the main lineages of A. wallichii. Instead, the intricate topography and heterogeneous habitats resulting from the drastic uplift of the Qinghai–Tibet Plateau from the Late Pliocene could be responsible for the intraspecific differentiation of A. wallichii. The present study further highlights the importance of geographic isolation and habitat heterogeneity in shaping and maintaining high species diversity within the HMR.  相似文献   

19.
本文基于6 个种群52 个个体的线粒体细胞色素b (Cyt b)基因全序列的遗传变异分析,探讨了我国长爪沙鼠种群的遗传结构和种群历史。在1140 bp Cyt b基因的碱基序列中,共发现了74个变异位点,其中转换和颠换位点分别为65和9个,共定义了37个单倍型。种群差异分析表明包头种群与其他种群之间都存在着显著的遗传差异,而其他种群间遗传差异则不显著。52 个个体在系统发生树中明显聚为两支(Clade A 和Clade B),其中Clade B 仅含有贺兰山东部种群中的3 种单倍型,而其余的单倍型分布于Clade A 中。来自Clade A 的49个个体的歧点分布分析结果呈单峰状,提示长爪沙鼠种群可能在历史上经历了种群增长和扩张事件,这一结果同时也得到了Tajima 检验结果(D=-1.86,P<0.05)和Fu 检验结果(Fs=-21.89,P <0.05) 的支持。通过种群扩张系数(τ)和分子钟的推算提示该种群扩张事件大约发生于11 万年前。我们的研究结果表明,长爪沙鼠在第四纪冰期中形成了明显的隔离分化,而贺兰山东部可能作为冰期避难所,包含于所有的谱系分支中,在末次间冰期种群进行了强烈的扩张,从而形成当今的分布格局。  相似文献   

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