长江下游地区4个克氏原螯虾群体的遗传多样性分析

为了对长江下游地区克氏原螯虾(Procambarus clarkii)群体的遗传多样性状况进行本底调查, 本文利用17对微卫星引物对南京(NJ)、盱眙(XY)、合肥(HF)、南昌(NC)4个克氏原螯虾地理群体进行了遗传多样性研究。结果表明, 4个地理群体的平均观测杂合度为0.4322–0.4826、平均期望杂合度为0.4024–0.6121、平均多态信息含量为0.3408–0.5624, 4个克氏原螯虾群体的遗传多样性处于中等水平, 其中南京群体遗传多样性最高, 合肥群体最低; 4个克氏原螯虾群体的基因流为1.3729–5.9161, 遗传分化指数为0.0405–0.1540, 群体间基因流水平较高, 群体间遗传分化程度较小。聚类结果显示4个群体可分为2支: 南京、南昌、盱眙三个群体聚为一支, 合肥群体独自成一支。以上结果将为克氏原螯虾遗传育种、资源保护和利用提供一定的理论依据。     

华南及邻近地区大刺鳅遗传多样性的ISSR分析

为了解我国大刺鳅野生资源状况, 研究采用ISSR技术分析了福建、广东、广西、云南和海南11个地理群体262尾大刺鳅的遗传多样性。10个引物共扩增出112个位点, 多态位点95个, 多态位点比例为84.82%。大刺鳅总群体Nei基因多样性h=0.2126、Shannon 信息指数I=0.3358, 表明大刺鳅总群体遗传多样性较丰富, 其中各群体遗传多样性依次为恩平 红河 屯昌 英德 河池 乐昌 增城 龙岩 五华 仁化 百色。总群体遗传分化系数Gst=0.4620, 显示46.2%的变异来自群体间。总群体基因流Nm=0.5823, 表明大刺鳅总群体间缺乏有效的基因交流, 遗传漂变是大刺鳅群体遗传分化的主要因素。聚类分析表明, 东江群体和韩江群体聚为一支, 西江群体和北江群体聚为一支, 大陆群体聚为一大支, 然后和海南屯昌群体聚类。     

银额果蝇自然群体中的mtDNA多态性研究──Ⅱ．银额果蝇的起源和分化

本文以８种限制性内切酶对８个银额果蝇群体进行了ｍｔＤＮＡ的限制性片段长度多态性（ＲＦＬＰ）分析。发现现生银额果蝇种群可以分成三个相对独立的群体,即东部、中部和西部群体。结合其它有关资料,我们推测,银额果蝇可能起源于马来半岛南部和加里曼丹岛一带。起初分成东西两支向北扩散。东支发展成现在的东部群体;西支则在中南半岛北部又分成两个支系;从而形成了现生银额果蝇群体的东部、中部和西部的地理分布模式。     

银额果蝇自然群体中的mtDNA多态性研究

本文以８种限制性内切酶对８个银额果蝇群体进行了ｍｔＤＮＡ限制性片段长度多态性分析,发现现生银额果蝇种群可以分成三个相对独立的群,即东部、中部和西部群体,结合其它有关资料,我们推测,银额果蝇可能起源于马来半岛南部和加里曼丹岛一带,起初分成东西两支向北扩散,东支发展成现在的东部群体;西支则在中南半岛北部又分成两个支系,从而形成了现生银额果蝇群体的东部、中部和西部的地理分布模式。     

应用微卫星标记分析23个中国地方马种的遗传多样性

为了调查中国马种的群体遗传分化与遗传结构状况, 本研究应用FAO和ISAG推荐的25对微卫星引物, 结合荧光标记PCR分析技术, 对中国23个马群体和1个英纯血马群体进行了分子遗传学研究。结果表明: 中国地方马群体的遗传多样性比较丰富, 23个中国马群体的等位基因数、多态信息含量和遗传杂合度等都高于英国纯血马。根据群体遗传距离构建的系统进化树, 能够清晰地将英纯血马从中国马中独立出来, 同时可将中国马群体分成不同的支, 基本上与其地理分布格局相符。我们用MVSP软件进行群体遗传分化分析可见, 前三个主成分的三维散点图可以明显地把英纯血马从所有群体中独立出来, 并把中国的马群体分成几个相对独立的支。进一步分析第一、二主成分的二维散点图, 可将中国的马群体分化成南方支系、藏马支系、新疆和青海支系、内蒙古支系及东北支系等5个部分。根据Structure软件分析, 推测中国马群体含有5个潜在的支系, 基本上代表了我国现在主要家马来源的基础遗传支系。这些信息可以为我国现有马种类型的划分与马种资源遗传多样性的保护提供科学依据。     

中国和美国大豆疫霉群体遗传结构的ISSR分析

为探究中国和美国大豆疫霉的遗传关系, 采用简单序列重复区间扩增多态性(ISSR)技术, 对来自中国黑龙江省、福建省和美国的3个大豆疫霉地理群体的遗传多样性进行了分析。通过13个ISSR引物对供试的111株大豆疫霉菌株进行扩增, 共得到102个ISSR条带, 其中多态性条带为88个, 占86%。遗传变异分析表明, 美国群体具有更高的遗传变异度; Nei’s 遗传相似性和主成分分析均显示, 中国福建群体与美国群体间的遗传相似性最高, 而福建群体与黑龙江群体间遗传相似性最低; 聚类分析显示, 供试菌株在88%的相似性水平上可区分为7个聚类组, 且美国群体分布于更多的聚类组中; Shannon-Wiener多样性指数也表明美国群体的遗传多样性最为丰富。综合分析表明, 本研究的结果不支持关于美国的大豆疫霉可能来源于中国的推测。     

福寿螺3个地理群体遗传多样性的AFLP分析

应用AFLP分子标记技术对我国江苏苏州、福建漳州和广东珠海3个地理群体福寿螺进行了遗传多样性分析.8对选择性引物在3个群体的90个个体中,共扩增出382个位点,多态位点369个.江苏、福建和广东3个福寿螺群体的多态位点比率和Shannon's指数分别为84.82%、85.08%、79.06%,0.4259、0.4308、0.4079;表明3个群体遗传多样性在同一水平上.不同地理来源的福寿螺个体归群分析聚成3类,与地理分布一致,表明3个地理群体间已出现遗传分化,广东群体和福建群体首先聚在一起,再与江苏群体聚类.Shannon's指数和AMOVA分析估算均显示福寿螺的遗传变异主要来自于群体内个体间.综上所述,3个福寿螺群体具有丰富的遗传多样性而且已形成相对独立的遗传结构;并找到了3个群体间遗传特异性AFLP标记,可用于群体间分子鉴定和辅助分类.     

斑鳜不同地理群体遗传变异的AFLP分析

斑鳜（Siniperca scherzeri Steindachner）为东亚地区特有的淡水名贵经济鱼类。受生态环境破坏和渔业捕捞过度的影响,斑鳜野生资源已呈下降趋势。为探明我国斑鳜不同地理群体的遗传背景,采用AFLP分子标记技术研究了鸭绿江、海河、长江、钱塘江、闽江、西江6个地理群体的遗传特征和群体分化。斑鳜65尾个体中,8对引物组合共扩增出211条带,其中多态性条带126条,多态比例为59.7％,并观察到一些群体的特异性条带。群体内的遗传变异以长江群体最大（6.7％）,群体间的遗传距离明显大于群体内的遗传距离。AMOVA分析表明,斑鳜6群体间的总遗传分化指数Fst= 0.7850（p <0.01）,群体间遗传分化极显著。聚类分析表明：斑鳜不同群体内的所有个体均单独聚群,6个地理群体明显分为南北两大群,鸭绿江群体和海河群体聚为一支,长江、钱塘江、闽江和西江四个群体聚为另一支。斑鳜较高水平的遗传变异与其地理分布范围广,在不同的生态环境下积累了的大量突变有关。不同地理群体间已产生了明显的遗传分化,其遗传亲缘关系与其地理分布格局基本一致,推测横亘于我国内陆中部地区、呈东西走向的秦岭山脉的形成可能是东亚斑鳜最先出现南北间群体分化的主要原因。     

斑鳜不同地理群体遗传变异的AFLP分析

斑鳜（Siniperca scherzeri Steindachner）为东亚地区特有的淡水名贵经济鱼类。受生态环境破坏和渔业捕捞过度的影响,斑鳜野生资源已呈下降趋势。为探明我国斑鳜不同地理群体的遗传背景,采用AFLP分子标记技术研究了鸭绿江、海河、长江、钱塘江、闽江、西江6个地理群体的遗传特征和群体分化。斑鳜65尾个体中,8对引物组合共扩增出211条带,其中多态性条带126条,多态比例为59.7％,并观察到一些群体的特异性条带。群体内的遗传变异以长江群体最大（6.7％）,群体间的遗传距离明显大于群体内的遗传距离。AMOVA分析表明,斑鳜6群体间的总遗传分化指数Fst= 0.7850（p <0.01）,群体间遗传分化极显著。聚类分析表明：斑鳜不同群体内的所有个体均单独聚群,6个地理群体明显分为南北两大群,鸭绿江群体和海河群体聚为一支,长江、钱塘江、闽江和西江四个群体聚为另一支。斑鳜较高水平的遗传变异与其地理分布范围广,在不同的生态环境下积累了的大量突变有关。不同地理群体间已产生了明显的遗传分化,其遗传亲缘关系与其地理分布格局基本一致,推测横亘于我国内陆中部地区、呈东西走向的秦岭山脉的形成可能是东亚斑鳜最先出现南北间群体分化的主要原因。     

日本囊对虾4个地理群体线粒体16S rRNA序列及遗传结构分析

对我国东南沿海日本囊对虾(Marsupenaeus japonicus)的4个地理群体广东群体(GD)、台湾群体(TW)、福建群体(FJ)和浙江群体(ZJ)的线粒体16S rRNA基因片段进行PCR扩增,对产物进行测序后分析。经比对获得470bp的核苷酸分析序列,发现了16个变异位点,得到了10种单倍型。广东、台湾、福建和浙江群体的核苷酸多样性依次分别为0.0008、0.0010、0.0051、0.0015,各群体均存在独有的单倍型和共有单倍型。群体遗传距离分析表明各群体间保持着一定的遗传差异,其中福建群体与其他群体之间存在着较远的遗传距离并保持了较高的遗传多样性。另外,利用其423bp的16S rRNA同源序列探讨了对虾科6个属共12种对虾的系统进化关系,囊对虾属与沟对虾属亲缘关系较近聚为一支,其他4个属的10种对虾聚为一支。     

光肩星天牛种群间及其近缘种遗传关系的RAPD研究

利用RAPD技术对采自中国和美国的星天牛属Anoplophora 5个种及8个光肩星天牛Anoplophora glabripennis (Motschulsky)地理种群共13个样品进行了遗传相似性分析。选用了Operon公司生产的引物H系列20个,L系列20个,Q系列11个共51个引物,最后从40个引物中筛选出26个具有多态性的引物作为第一组用于星天牛属种间和光肩星天牛种群间分析,从31个引物中筛选出19个具有多态性的引物作为第二组单独用于光肩星天牛种群分析。根据第一组引物实验获得的RAPD聚类图及遗传距离表明,各个地理种群的光肩星天牛和黄斑星天牛A. nobilis都聚在一起,形成一个大的分枝,而四川星天牛A. freyi、楝星天牛A. horsfieldi和星天牛A. chinensis均在此分枝之外。来自美国纽约和芝加哥的光肩星天牛种群聚于中国光肩星天牛种群之外的另一个独立的分枝上。分布在我国宁夏、内蒙古和河北的光肩星天牛以及宁夏黄斑星天牛和山东、陕西的光肩星天牛分别聚在一起,而甘肃的光肩星天牛与甘肃的黄斑星天牛则聚于另一枝,且它们之间的遗传距离很近,仅为0.1324,说明这两者之间有着极其相近的亲缘关系,由此推断光肩星天牛和黄斑星天牛的差异很小,遗传关系难以区分,进一步证实了它们很可能是同一个种下的两个不同的型。第二组引物实验得到了相似的结果,来自中国的6个光肩星天牛种群全部聚于同一枝中并分成两小枝： 分布于我国宁夏、河北、山东、甘肃的光肩星天牛聚在一起,内蒙古和陕西的光肩星天牛则成另一枝,而分布于美国纽约和芝加哥的光肩星天牛仍聚于中国光肩星天牛种群之外的一个单独的分枝上。但是美国光肩星天牛与中国光肩星天牛之间的遗传距离最近的为0.4578, 最远的为0.5960。由此认为,本研究中采自美国的两个光肩星天牛种群的样本和采自中国的光肩星天牛种群的样本之间存在显著差异,遗传关系较远。有必要从中国和世界其他天牛分布地采集更多样本做进一步DNA 分析。     

青藏高原垂穗披碱草遗传变异的地理因素分析

采用等位酶标记对我国青藏高原地区垂穗披碱草的9个种群进行遗传变异和系统关系分析.结果表明,不同种群间遗传距离范围在0.010 6-0.377 8,种群间遗传距离和地理环境关系密切.采用聚类分析和二维、三维Mantel检验,对青藏高原垂穗披碱草(Elymusnutans Griseb.)不同种群间遗传距离与环境条件的关系(纬度、经度和海拔)进一步分析发现,海拔和地理位置(纬度和经度)均明显影响垂穗披碱草种群遗传差异.种群间遗传距离和海拔(R=0.476 8)、地理位置(R=0.447 1)均呈现显著正相关,种群间遗传距离随着海拔、地理位置差距的增大而增加,但海拔是影响其遗传结构的最重要因素,其次是经纬度.     

福建南北泥蚶种内分化的RAPD分析

采用随机扩增多态性DNA(RAPD)技术,对泥蚶在福建以南(广东汕头和湛江)和福建以北(浙江温岭和韩国)种群(分别合称南方类群和北方类群)做了遗传分化研究。由筛选出的20个随机引物共获得103个清晰可辨的RAPD标记,扩增片段长度在250—2500bp。汕头种群与湛江种群,韩国种群与温岭种群之间的最小遗传距离分别为0．0612和0．0692,而南、北类群间的遗传距离却在0．3261-0．4511。类群间近交系数也大于类群内。NJ和UPGMA法构建的系统树均显示汕头种群、湛江种群首先聚在一起,再与温岭种群和韩国种群聚合,说明两个类群发生了较明显的遗传分化,估计与地理隔离有关。     

Genetic variation and differentiation at microsatellite loci in Drosophila simulans. Evidence for founder effects in new world populations.

Drosophila simulans isofemale lines from Africa, South America, and two locations in North America were surveyed for variation at 16 microsatellite loci on the X, second, and third chromosomes, and 18 microsatellites, which are unmapped. D. simulans is thought to have colonized New World habitats only relatively recently (within the last few hundred years). Consistent with a founder effect occurring as colonizers moved into these New World habitats, we find less microsatellite variability in North and South American D. simulans populations than for an African population. Population subdivision as measured at microsatellites is moderate when averaged across all loci (FST = 0.136), but contrasts sharply with previous studies of allozyme variation, which have showed significantly less differentiation in D. simulans than in D. melanogaster. There are substantially fewer private alleles observed in New World populations of D. simulans than seen in a similar survey of D. melanogaster. In addition to possible differences in population size during their evolutionary histories, varying colonization histories or other demographic events may be necessary to explain discrepancies in the patterns of variation observed at various genetic markers between these closely related species.     

Genetic structure of insular Mediterranean populations of the house mouse

The genetic structure of six western Mediterranean island populations of Mus musculus domesticus were investigated by means of an electrophoretic analysis at 34 loci and compared to that of five neighbouring mainland populations. No reduction in variability (H = 0.09 for both island and mainland samples) was observed in the island populations except for a very small island (6 ha), in which one-third of the variability was lost. Patterns of colonization inferred from a Wagner cluster analysis and the distribution of rare variants suggest that, although these island populations are clearly related to European mainland mice, their genetic structure is the result of multiple founding events from sources dispersed throughout the Mediterranean Basin. Furthermore, the presence of the same rare alleles in Sardinia, Corsica and Piana, suggest that the three islands share a common history of colonization.
Estimates of genetic distance and gene flow indicate that the level of genie differentiation is greater between island and mainland populations that between the latter due to geographic isolation. Multiple founder events and post-colonization evolution are the factors that best explain the observed levels of genie variability and differentiation in these Mediterranean islands.     

Genetic divergence among geographical populations of the migratory locust in China

The random amplified polymorphic DNA (RAPD) technique was used to examine genetic divergence and interrelations of 11 geographical populations of the migratory locust in China, and the role of spatial separation in the population differentiations. AMOVA analysis of genetic variations in all the populations indicated greater within- (79.55%) than among-population variability (20.45%), and that there were significant differentiations among the populations; 11 populations were divided into four regional groups, with significantly greater variability within (82.99%) than among the groups (17.01%), and there existed apparent regional differentiations. Paired comparisons showed significantly greater variability within-than between-groups, indicating significant differentiations between populations of different regional groups. Of all the pairwise comparisons, Hainan and Tibetan groups displayed the greatest differentiation, with the difference between the two groups being seven folds of that between populations within the groups; the least differentiations were exhibited between the groups of Hainan, Xinjiang, and Inner Mongolia, with the differences between groups being only half of the differences between populations within the groups. Mantel tests of the genetic and spatial distances showed that the two matrices were significantly correlated (p<0.01), indicating that the geographical isolation played an important role in the differentiations of the geographical populations of the migratory locusts. Cluster analysis divided all populations into four major groups: Xinjiang and Inner Mongolia group, the Great Plains of North China (the Yellow River and Huai River Plains) group, Hainan group, and Tibet group. Principal component analysis (PCA) supported the division of populations based on the cluster analysis. However, analysis of individuals clustered the locusts into five populations: Xinjiang and Inner Mongolia, Hami in Xinjiang, the Great Plains of North China, Hainan, and Tibet. The locust populations in eastern China displayed apparently continous and gradient variations; as such authors consider that there were no necessity and valid reasons for further division of subspecies. The subspecific status for the main geographical populations of the migratory locusts in China was discussed.     

Genetic structure and variation in the relict populations of Alsophila spinulosa from southern China based on RAPD markers and cpDNA atpB-rbcL sequence data

RAPD markers and sequences of chloroplast DNA (cpDNA) atpB-rbcL intergenic spacers were used to characterize the pattern of genetic variation and the phylogenetic relationships of the relict populations of Alsophila spinulosa located in Jian Feng Ling (JFL) and Diao Luo Shan (DLS), Hainan, and Tang Lang Shan (TLS), Ding Hu Shan (DHS), and Da Xi Shan (DXS), Guangdong, of southern China. 28 random primers generated 118 bands, out of which 26 (22.03%) were polymorphic loci, distinguishing 17 different RAPD phenotypes. Percentage of polymorphic loci, Shannon phenotypic diversity and Nei's gene diversity comprehensively indicated that JFL possessed the highest diversity, TLS and DHS in intermediate and DLS or DXS the least; the corresponding values of the population appeared correlated with the population size. Differentiation was detected among populations of A. spinulosa (1-Hpop/Hsp=0.7453, GST=0.7763, and phist=0.8145). AMOVA showed that 47.44% of the variance was partitioned among regions (Hainan and Guangdong), 34.01% attributed among populations within regions, whereas only 18.55% occurring within populations. Low level of intra-specific diversity was maintained in A. spinulosa with Shannon diversity and gene diversity merely 0.0560 and 0.0590, repectively. Sequence length of atpB-rbcL intergenic spacer varied from 724 bp to 730 bp. Base composition was with A+T content between 63.17% and 63.70%. 13 haplotypes of atpB-rbcL noncoding spacers were identified. UPGMA dendrogram of RAPD phenotypes, principal components analysis based on RAPD patterns, minimum spanning network and neighbour-joining (NJ) tree established on atpB-rbcL haplotypes consistently suggested the geographical subdivision of populations of A. spinulosa between Hainan and Guangdong. Breeding system and conservation strategy of A. spinulosa was discussed based on the information of population genetic structure and variation.     

Genetic divergence among geographical populations of the migratory locust in China

The migratory locust, Locusta migratoria L., which is distributed widely in the East Hemisphere, has long been regarded as the most important agricultural pest and a model insect. Its distribution ranges from thetropic and the subtropical zone, to the temperate zone, and to the cold-temperate zone. Because of the wide geographical distribution and adaptations, many geo- graphical populations of the migratory locust dis- played apparent variation in morphology, life history, physiology, and ot…     

影响披碱草属植物遗传分化和亲缘关系的地理因素分析

用微卫星标记法对产自中国青藏高原和蒙古高原地区9种披碱草属（Elymus L．）植物的40个居群进行遗传变异和亲缘关系分析,居群问遗传相似系数为0．020～0．957,居群间遗传距离与地理因素关系密切。以垂穗披碱草（Elymus nutctns Griseb．）为例,采用二维和三维Mantel检验,对遗传距离和地理因素间的关系（纬度、经度和海拔）作进一步分析,结果表明,地理位置（纬度和经度）是影响垂穗披碱草居群微卫星遗传差异的最重要因素（R=0．478;P＜0．05）,其次是海拔（R=0．258;P＞0．05）。单一地理位置因素（纬度或经度）与遗传距离的相关性并不明显,但从单一地理位置因素与遗传距离的相关系数、可信度区间来看,纬度对遗传分化的影响程度大于经度。     

我国烟蚜种群分化的RAPD分析

用RAPD-PCR技术研究了我国烟草上烟蚜Myzus persicae (Sulzer)的种群分化。结果表明：我国烟蚜的不同地理种群和不同体色之间DNA均呈现出多态性,且不同的引物可在不同水平上反应出烟蚜种群的DNA多态性。Nei的遗传距离表明我国烟草上烟蚜的分化仅在种群水平上,并未达到亚种水平。用相似性指数和Nei的遗传距离对所筛选的三个引物OPX-04、OPX-06和OPX-19的扩增结果进行聚类,虽然二者的结果不一致,但均可反应出烟蚜的地理种群和体色生物型的DNA差异。在DNA水平上,与完全周期生活史的烟蚜相比,完全周期和不完全周期生活史混合发生的烟蚜与不完全周期生活史的烟蚜更为接近,而两种生活史混合发生的烟蚜之间无明显差异。从体色看,红色比黄绿色更接近褐色。