云南穗花杉的遗传多样性研究

采用随机扩增多态DNA(RAPD)方法对云南穗花杉(Amentotaxus yunnanensis)4个居群和台湾穗花杉似(Amentotaxus for9rmosana)1个居群共104个个体进行了遗传多样性分析。9个随机引物共扩增出清晰谱带143条。云南穗花杉在物种水平上遗传多样性较高(多态位点百分率P为79．0％,基因多样性指数He为0．2718),但云南穗花杉和台湾穗花杉居群内遗传多样性均较低(P为18．0％、6．9％;He为0．0688、0．0198)。云南穗花杉居群间遗传分化强烈(AMOVA,GST和Shannon多样性指数分别为0．7611,0．7503和0．7526)。据推测,第四纪冰川引起的瓶颈效应,小规模居群引起的遗传漂变及幼苗成活率低等因素都加剧了居群间的遗传分化。建议对所研究的云南穗花杉全部居群予以保护,特别是对云南西畴和贵州兴义市七舍两个具有相对较高遗传多样性的居群应该优先建立就地保护点,以达到最大限度保存云南穗花杉遗传多样性的目的。     

濒危灌木长叶红砂遗传多样性的RAPD分析

应用RAPD分子标记对濒危灌木长叶红砂(Reaumuria trigyna)种群遗传多样性进行了分析.应用18条随机引物对长叶红砂5个种群的95个个体进行扩增,检测到118个位点,其中多态位点105个.结果表明:长叶红砂种群的多态位点比率(P)为88.98%,显示出长叶红砂种群存在较高的遗传多样性.Shannon多样性指数(0.4966)、Nei基因多样性指数(0.3303)和基因分化系数(Gst=0.1425)的分析结果显示,长叶红砂种群遗传变异大多存在于种群内,种群间的遗传分化占14.25%.聚类分析表明,长叶红砂种群遗传距离与地理距离之间无直接相关关系.遗传多样性水平与物种特性和所处不同群落有关,濒危植物并不一定表现为遗传变异水平的降低.     

云南金钱槭 等位酶 遗传多样性 生境片段化 保育策略

云南金钱槭（Dipteronia dyeriana）是我国特有的国家Ⅱ级重点保护珍稀濒危植物,仅分布于云南的文山、屏边和蒙自三县交界地区。采用水平切片淀粉凝胶电泳等位酶分析方法,对采自三个县的天然居群的63个样品进行了遗传多样性检测。8个酶系统的13个等位基因位点分析表明,云南金钱槭的遗传多样性水平低,其平均多态位点百分率P=15.4%,每位点平均等位基因数A=1.2,平均预期杂合度He=0.064,各居群都偏离Hardy-Weinberg平衡,杂合子过量,居群间的基因分化系数GST=0.099,遗传变异主要发生在居群内（90.1%）,居群间分化较小,居群间遗传一致度较高（I=0.985～1）,具有一定的基因流（Nm=2.669）。不加权对平均法（UPGMA）聚类可将4个居群分为两支,水头箐居群和马家寨居群亲缘关系最近,聚类后与黑洞居群形成一支再和中槽子居群聚类,这与其地理分布格局大致吻合。据此提出了关于云南金钱槭保育策略的建议。     

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。     

Genetic Diversity in Cymophyllus fraserianus (Cyperaceae), a Rare Monotypic Genus

Cymophyllus fraserianus (Fraser's sedge) is a rare perennial evergreen herb found in late-successional forest communities in the Appalachian Mountains of the U.S. Genetic diversity was assessed at 19 allozyme loci for 12 populations sampled from the southern and central portions of the range of this primitive monotypic genus. Species variation was comparable to that found for other narrowly distributed species, although mean population genetic diversity was somewhat higher. Sixteen of the 19 loci (84%) were polymorphic, with a mean of 46% polymorphic within populations. On average, 2.7 alleles were detected per polymorphic locus. Genetic diversity within populations (Hep) averaged 0.113, whereas species' genetic diversity (Hes) was 0.131. Although a twofold range of within-population genetic diversity (Hep = 0.075-0.158) was found, less than 13% of the genetic variation was distributed among populations (G(ST) = 0.129). An indirect estimate of historical levels of gene flow (Nm = 1.69) was consistent with the high mean genetic identity (mean I = 0.96) found between populations. Despite the relictual nature of C. fraserianus, its rarity and fragmented distribution, genetic diversity within the genus is typical of herbs with similar life-history characteristics. No association was found between geographic and genetic distances between populations (r = -0.01; p > 0.9), suggesting that present day populations are relatively isolated.     

Allozyme Variation and the Genetic Structure of Populations of the Rare Sedge Carex misera (Cyperaceae)

Abstract Carex misera is a rare sedge, endemic to rocky outcrops and mountain summits within the southern Appalachian Mountains from northern Georgia to northern North Carolina. We assessed allozyme diversity for 406 individuals from nine populations over most of the geographic range. Twenty-seven putative loci were assayed and eight (30%) were found to be polymorphic. Nei's gene diversity statistics ( H _T =0.043, H _S =0.019, G _ST =0.551) indicated low levels of variation but relatively highly differentiated populations, suggesting little gene flow. Significant deviations from genotypic expectations under Hardy-Weinberg equilibrium, high positive fixation indices, and the existence of small genetic neighborhoods within populations suggest that at least some inbreeding occurs. Cluster analysis of Nei's genetic identity statistics and principal component analysis of allele frequency data showed high similarity among the six southern populations with the two northern populations more differentiated from them and from each other. These results suggest that preservation of the northern populations is necessary to conserve the already low levels of genetic diversity within the species.     

华中特有珍稀植物裸芸香的AFLP遗传多样性分析

采用选择性扩增片段多态性(AFLP)方法对华中特有单种属植物裸芸香(Psilopeganum sinense)的8个自然居群的遗传多样性进行了检测与分析。结果表明:裸芸香的遗传多样性较低,且居群内遗传多样性显著低于物种水平遗传多样性。筛选出的5对引物共得到180个位点,76个为多态位点,多态位点百分率为42.2%,8个居群多态位点百分率为:3.3%～16.7%,居群平均多态位点百分率为9.4%;8个居群Nei多样性指数为0.01987～0.06987,Shannon’s多样性指数为0.0197～0.0816。居群间分化系数Gst=0.5069,居群间基因流为0.2432,不足以维持居群间的基因交流及现有的遗传结构。AMOVA分析表明总遗传变异的13.17%存在于4个地理区域之间,50.45%存在于地理区域内的居群间,36.38%的遗传变异存在于居群内个体间。NTSYS分析表明遗传距离与地理距离不存在相关关系。UPGMA聚类结果表明长江南北两岸的居群并没有产生明显分化。最后,分析了裸芸香的濒危原因并提出了有效的保育措施。     

云南灯盏花遗传变异的RAPD分析

运用RAPD (randomamplifiedpolymorphicDNA)技术对云南灯盏花 (Erigeronbrevis capus) 6个居群进行分析 ,研究其遗传变异及遗传结构 ,用外类群紫菀对比分析其亲缘关系。随机挑选 16个引物在 6个居群中共产生 2 33条DNA片段 ,其中 192条带具有遗传多态性 ,约占 82 4 0 %。多态位点百分比PPB、等位基因数A、有效等位基因数Ae、Nei’s基因多样性指数H和Shannon多样性指数I在物种水平分别为 82 4 0 %、 1 82 4 0、 1 30 0 5、0 1896、 0 30 2 1;居群的平均值分别为 5 4 2 3%、 1 5 40 1、 1 2 6 91、 0 16 0 7、 0 2 4 6 0。灯盏花的遗传多样性较丰富 ,基因分化系数Gst值为 0 346 0 ,有 6 5 4 0 %的变异来自居群内 ,6个居群的遗传一致度较高 ,在 0 90 37～ 0 972 3之间 ,平均为 0 94 10。利用UPGMA对 6居群聚类分析 ,结果表明 :丘北居群 (YB)和文山居群 (YX)亲缘关系最近 ,小哨居群 (Y )和新平居群 (YA)次之 ,丘北居群 (YB)和腾冲居群 (ZA)亲缘关系最远。遗传关系与各居群地理分布区间的距离大致成正相关     

广西地不容种质资源的ISSR分析

采用简单序列重复区间扩增(ISSR)分子标记技术对广西地不容3个野生居群和1个引种居群共92个个体进行了遗传多样性研究。10个引物共扩增出61条带,其中60条具多态性,多态性位点百分率为98.36%。4个居群多态性百分率在73.77%～86.89%。Nei’s基因多样性指数(H)为0.3379,Shannon信息多样性指数(Ⅰ)为0.5055。3个野生居群Nei’s遗传分化系数(Gst)表明:83.87%遗传变异分布在居群内,16.13%的遗传变异分布在居群间。引种居群与3个野生居群间的遗传一致度达0.8846。引种居群有效地保护了广西地不容的遗传多样性。     

大王马先蒿云南五个居群遗传变异研究

采用随机扩增多态DNA(RAPD)分子标记方法,对大王马先蒿(PedicularisrexL.)分布在云南中甸、丽江、大理、武定和昆明的5个居群(其中中甸居群有3个亚居群)的遗传多样性和遗传结构进行了研究。结果表明,大王马先蒿居群具有较高的遗传多样性,多态位点百分率P、Shannon表型多样性指数I和Nei的基因多样性指数h分别为82.0%、0.361和0.240,遗传多样性水平与居群的地理分布范围相关;大王马先蒿居群间的遗传变异较高,遗传变异主要发生在居群之间,而不是居群内部;居群间遗传分化系数Gst为0.747,遗传分化明显,居群间基因交流较少。居群间的遗传距离与居群间的相对地理距离具有一定的相关性。对云南西北部中甸居群的3个亚居群的遗传多样性分析表明,居群的遗传多样性水平与海拔高度有一定的相关性。居群间遗传变异较高可能是由于大王马先蒿为短命多年生植物,繁育系统为混交型,且自交占较大比例等原因造成的。     

Genetic structure of endangered Emmenopterys henryi Oliv. based on ISSR polymorphism and implications for its conservation

Inter-simple sequence repeat (ISSR) markers were used to determine the genetic variation and genetic differentiation of nine populations of Emmenopterys henryi Oliv., an endangered plant endemic to China. Relatively low genetic diversity was detected at population level (the percentage of polymorphic loci P=22.56%, the number of alleles per locus A=1.183+/-0.045, the effective number of alleles per locus A(E)=1.007+/-0.345, Nei's gene diversity h=0.071+/-0.017, Shannon information index I=0.104+/-0.025). However, the genetic diversity at species level was relatively high (P=56.05%; A=1.561+/-0.498, A(E)=1.325+/-0.371, h=0.191+/-0.199, I=0.287+/-0.284). Analysis of molecular variance showed that most of the ISSR variation (68.03%) in E. henryi occurred among populations. The estimated Nm from F (ST )was 0.235. It indicated that the fragmentation and isolation of populations might result from specific evolutionary history and anthropogenic activity. Consequently, genetic drift might play an important role in determining the genetic structure of E. henryi. Conservation strategies for this endangered species are proposed based on the genetic data.     

应用ISSR-PCR分析蒙古栎种群的遗传多样性

本研究应用ISSR标记技术对东北地区的优势树种蒙古栎(Quercus mongolica)的25个种群遗传多样性进行了分析, 目的是为蒙古栎早期选择提供依据。从60条ISSR引物中筛选出10个特异性强、稳定性好的引物进行ISSR分析。共获得位点数71个, 其中多态位点数56个, 多态位点百分率为78.87%。PopGene分析结果表明: 种群的平均多态位点百分率为45.2%, Shannon表型多样性指数(I)平均值为0.25, 具有较高的遗传多样性, 种群间存在一定程度的基因流(N_m为1.3818)和遗传分化(Nei’s信息多样性指数平均值为0.1068, G_st平均值为0.2657), 种群内的基因多样度占总种群的73.43%, 种群间占26.57%, 表明蒙古栎种群的变异主要来源于种群内。结合聚类分析和地理变异规律把种群划分为两个大的种群组: 小兴安岭种群组和长白山种群组。以上结果可为栎属种质资源的保护和利用以及物种分化研究提供基础资料。     

Genetic variability and differentiation of Caragana microphylla populations as revealed by RAPD markers

Genetic variability in random amplified polymorphic DNA (RAPD) was studied in 90 individuals of Caragana microphylla, an outcrossing perennial shrub species, from five natural populations sampled in Inner Mongolia steppe of China on a small scale. Nineteen selected primers were used to amplify DNA samples, and totally 225 bands were detected. The percentage of polymorphic bands within populations ranged form 58.22% to 63.56%, with an average of 60% at the population level and 71.11% at the species level, indicating relatively high genetic variations in C. microphylla species. Shannon's information index (I) and Nei's gene diversity (h) showed the similar trend with each other. According to the analysis of Nei's gene diversity, the percentage of genetic variation among populations was 7.13%, indicating a low level of genetic differentiation among populations. There existed a strong gene flow (Nm = 3.26) among populations. Although AMOVA analysis also revealed most variation was within populations (phi(ST) = 4.1%), a significant proportion was observed among populations (P<0.001) in the present study, suggesting genetic differentiation occurred among populations at a certain extent. Based on Mantel's tests and the results of previous studies, the genetic structure pattern of C. microphylla accorded with the isolation-by-distance model on a very large scale, however, on a small scale, the significant genetic differentiation among populations might be enhanced by the micro-environmental divergence among the sampling sites, rather than by geographic factors. Analysis of the genetic variations of C. microphylla populations provided useful information for the adaptive strategy of Caragana species.     

西藏地区雪层杜鹃遗传多样性的AFLP分析

采用AFLP技术对西藏地区雪层杜鹃（Rhododendron nivale）5个天然种群135份材料进行遗传多样性和遗传分化研究。筛选得出的6对引物共扩增产物273条DNA片段,扩增多态位点百分率为85.71%。5个雪层杜鹃种群的遗传多样性指标表现了相似的变化趋势,Nei基因多样性指数（h）和Shannon信息指数（I）的变化趋势一致,均为工布江达县种群 < 米林种群 < 嘎隆拉种群 < 色季拉山种群 < 红拉山种群。POPGENE分析结果表明雪层杜鹃在物种水平（PPL=85.71%,I=0.415 1,h=0.273）具有较高的遗传多样性,种群水平（PPL=62.26%,I=0.280 3,h=0.184 1）的遗传多样性较低。AMOVA分析结果表明36%的遗传变异存在于种群间,64%的遗传变异存在于种群内,雪层杜鹃种群间的遗传分化系数（G_st=0.324）与AMOVA分析得到的遗传变异分布结果一致。UPGMA聚类结果说明雪层杜鹃的遗传距离与地理距离和海拔高度没有明显的相关性。综合分析,引起雪层杜鹃的遗传变异的原因可能是地理环境不同和种群的生境类型差异。最后就雪层杜鹃的合理开发和保护提出建议。     

Isolation by distance and vicariance drive genetic structure of a coral reef fish in the Pacific Ocean

We studied the genetic diversity of a coral reef fish species to investigate the origin of the differentiation. A total of 727 Acanthurus triostegus collected from 15 locations throughout the Pacific were analyzed for 20 polymorphic loci. The genetic structure showed limited internal disequilibrium within each population; 3.7% of the loci showed significant Hardy-Weinberg disequilibrium, mostly associated with Adh*, and we subsequently removed this locus from further analysis of geographic pattern. The genetic structure of A. triostegus throughout the tropical Pacific Ocean revealed a strong geographic pattern. Overall, there was significant population differentiation (multilocus F(ST) = 0.199), which was geographically structured according to bootstraps of neighbor-joining analysis on Nei's unbiased genetic distances and AMOVA analysis. The genetic structure revealed five geographic groups in the Pacific Ocean: western Pacific (Guam, Philippines, Palau, and Great Barrier Reef); central Pacific (Solomons, New Caledonia, and Fiji); and three groups made up of the eastern populations, namely Hawaiian Archipelago (north), Marquesas (equatorial), and southern French Polynesia (south) that incorporates Clipperton Island located in the northeastern Pacific. In addition, heterozygosity values were found to be geographically structured with higher values grouped within Polynesian and Clipperton populations, which exhibited lower population size. Finally, the genetic differentiation (F(ST)) was significantly correlated with geographic distance when populations from the Hawaiian and Marquesas archipelagos were separated from all the other locations. These results show that patterns of differentiation vary within the same species according to the spatial scale, with one group probably issued from vicariance, whereas the other followed a pattern of isolation by distance. The geographic pattern for A. triostegus emphasizes the diversity of the evolutionary processes that lead to the present genetic structure with some being more influential in certain areas or according to a particular spatial scale.     

大别山山核桃天然群体遗传结构的初步分析

利用RAPD分子标记技术检测了大别山山核桃3个天然居群的遗传多样性和遗传结构。20条10 bp随机引物共检测到238个扩增位点,其中多态性位点162个,多态位点百分率(PPB)为68.1%。居群水平Shannon’s多态性信息指数(I)介于0.2651~0.2801之间;居群水平Ne i’s基因多样性指数(H)介于0.1789~0.1890之间。遗传变异计算显示大别山山核桃居群间基因分化系数(Gst)为0.4063,分子方差分析(AMOVA)表明居群间基因分化水平为0.4177,居群间基因流(Nm)为0.7306,说明大别山山核桃大部分变异存在于居群内,居群间基因交流相对较少。这一结果符合大别山山核桃风媒、异交的繁育系统特点,但其居群间基因分化程度明显高于异交植物的平均水平(Gst=0.1930)。地理隔离、居群内近交及居群间基因流受阻可能是形成目前大别山山核桃天然群体遗传结构的主要因素。     

Genetic diversity within and between natural populations of Rattus norvegicus

The levels of gene diversity for 17 polymorphic loci in natural populations of wild rats were examined for three separate locations in North and South America. The level of gene diversity in the total sample for the RT1.A locus, the dominant class I histocompatibility locus in the major histocompatibility (RT1) complex of the rat, was 0.807. The degree of gene diversity for nonalloantigenic loci scattered throughout the rat genome was 0.215, a level comparable to, if not slightly higher than, that for other mammalian species. The large and consistent levels of diversity for individuals within each population suggest that significant deviations from random mating have occurred within each group. Conclusions from analyzing genetic distance and the index of genetic differentiation between the three populations are consistent with these populations' geographic isolation and small effective population size. Assuming that the separation of the North and South American groups has existed for approximately 300 years, the effective size of these populations is estimated to be approximately 1,500 individuals. Apparent differences in the distribution of the number and frequency of alleles in the major histocompatibility complexes of mice and rats and the level of genetic differentiation among separate rat populations may be due to the effects of genetic drift in small populations.     

Low genetic diversity and high genetic differentiation in the critically endangered Omphalogramma souliei (Primulaceae):implications for its conservation

Omphalogramma souliei Franch. Is an endangered perennial herb only distributed in alpine areas of SW China. ISSR markers were applied to determine the genetic variation and genetic structure of 60 individuals of three populations of O. Souliei in NW Yunnan, China. The genetic diversity at the species level is low with P= 42.5% (percentage of polymorphic bands) and Hsp=0.1762 (total genetic diversity). However, a high level of genetic differentiation among populations was detected based on different measures (Nei's genetic diversity analysis: Gst=0.6038; AMOVA analysis: Fst=0.6797). Low level of genetic diversity within populations and significant genetic differentiation among populations might be due to the mixed mating system in which xenog-amy predominated and autogamy played an assistant role in O. Souliei. The genetic drift due to small population size and limited current gene flow also resulted in significant genetic differentiation. The assessment of genetic variation and differentiation of the endangered species provides important information for conservation on a genetic basis. Conservation strategies for this rare endemic species are proposed.     

采用RAPD标记探讨瓣蕊唐松草(毛茛科唐松草属)的遗传多样性及其地理分布格局(英文)

Random amplified polymerphic DNA(RAPD)method was applied to assessg enetic variation and population structure of Thahctrum petalotdeum L(Ranunoulaceae),Two hundred and forty-six individuals from 11 populations of the species were investigated by RAPD profiles Twenty selected RAPD primers generated 125 bands．in which 120 were polymorphic Ther esults revealed a high level of genetic variation(ercentage of polymorphIc bands(PPB was 96％．Nei’s gene diversity(りwas 03502 and shannon’s information index(I) was 0．5199 at the species level) The differentiation among the populations was high(Gst=0．3511)in this species．Result of analyzing of molecularvariance(AMOVA)showedthat38．88％of genetic variance was found among the populations Positive correlation withr r=01945(P=00002)was found between genetic distance and geographic distance amongpo pulations Two populations distributed in the drainage basin of YanELz River affined genedcally and formed one clada and the rest nine populations formed the other clade in both unweighted pair-group method using arithmetic average(UPGMA)trees made by two different method different methods. It was yen/clear that these two populations were very special, andmust be closely related in history, despite the fact that they now share quite weak link to the restpopulations through gene communication.     

苍术（Atractybeslancea（Thunb．）DC．）种内遗传多样性分析

分析了苍术（Ａｔｒａｃｔｙｌｏｄｅｓｌａｎｄｅａ（Ｔｈｕｎｂ．）ＤＣ．）５种等位酶（ＭＤＨ,ＧＤＨ,ＰＰＯ,ＳＯＤ,ＰＥＲ）１２个位点上２５个等位基因的分化特征。结果表明：群体内多态位点比例平均为０．６１,每个位点的平均杂合率为０．２６,每个位点发现的平均等位基因数为１．７８。苍术种内基因多样性的８６％产生在群体内,群体间分化的明显效果为１４％。所有配对组合,群体间的平均遗传距离是０．１１,遗传同一性是０．９０。说明苍术种内变异很大。同时探讨茅苍术的分类位置,认为茅苍术不是苍术和白术的杂交种。