不同种群海南粗榧(Cephalotaxus mannii)遗传多样性研究

采用垂直板型凝胶电泳技术 ,对海南粗榧 5个种群的遗传多样性进行了研究 ,结果表明 :海南粗榧遗传多样性水平低 ,多态位点比率 P=0 .3 3 ,等位基因平均数 A=1 .3 3 ,平均期望杂合度为 He=0 .1 3 5 ,观察杂合度 Ho=0 .1 3 9,黎母山种群所具有的相对丰富的遗传多样性使其成为保护和科研的重点     

胡卢巴等位酶变异和遗传多样性研究

采用聚丙烯酰胺凝胶电泳技术,对33份胡卢巴(Trigonella foenum-graecum L.)种质资源的5个酶系统 24个酶位点的变异和遗传多样性进行初步分析.结果表明:参试胡卢巴的遗传多样性水平较高,物种水平上的遗传多样性参数:多态位点百分数(P)为75.0%,平均每位点的等位基因数(A)为1.75,平均期望杂合度(He)为0.352;种源水平上的平均遗传多样性参数:P=70.6%,A=1.87,He=0.422.各种质资源间基因分化系数(GST)为0.026;基因流(Nm)的平均值为26.14,表明胡卢巴不同种质资源间基因分化水平低,基因交流频繁.聚类分析结果显示,来自中国不同地区的胡卢巴亲缘关系较近,而国外胡卢巴和国内胡卢巴的亲缘关系相对较远.     

缙云山特有植物缙云黄芩的遗传多样性研究

采用聚丙烯酰胺凝胶垂直平板电泳检测了重庆缙云山特有植物缙云黄芩7个居群70个个体的过氧化物酶、细胞色素氧化酶、超氧化物歧化酶、淀粉酶和酯酶5种等位酶,获得20个基因位点的资料,由此分析了其遗传分化水平。结果表明：缙云黄芩遗传多样性水平较高,多态位点比率P为45．7％,平均每个多态位点的等位基因数目A为1．46,平均预期杂合度He为0．205,平均观察杂合度Ho为0．352。缙云黄芩居群间遗传分化水平较高,Gst=0．401,居群间遗传一致度和遗传距离的平均值分别为0．741和0．300。缙云黄芩遗传多样性的40．1％来源于居群之间的基因差异,59．9％属于居群内的遗传分化,因而对缙云黄芩遗传多样性的保护,应保护其较多的居群。     

滇东南硬叶兜兰核心种质区群体遗传结构

本研究选取国内主要种质采集区-滇东南石灰岩地区7个不同干扰居群为研究对象,旨在对其居群内和居群间遗传变异进行比较研究,以期对其保护措施的提出提供理论依据。通过利用SRAP标记对167个体的遗传多样性和遗传结构研究,结果表明：10对SRAP引物共扩增出288个位点,多态位点比率（PPB）达81.25%,香侬指数（I）为0.3709,在种水平上的具有较高遗传多样性;而居群水平上的多态位点比率仅为47.92%, 香侬指数为0.2348, 居群间平均Nei’s遗传距离为0.1268。经分子遗传变异方差分析（AMOVA）表明,有66.27%的遗传变异来源于居群内,居群间变异占总变异33.73%,此结果与遗传分化系数（Gst=0.3568）结果吻合,居群间基因流（Nm）为0.902, 不同地区间硬叶兜兰居群存在较高的遗传分化; 7个居群的UPGMA聚类在遗传相似性系数达0.863,聚为两支;经Mantel检测（r =0.298, P＞0.05）,表明居群间遗传距离与地理距离无显著相关性。居群当前较高的遗传分化与其交配系统有关,其次,外在因素：人为采集、生境破坏和片断化造成居群内遗传多样性的丧失,加剧居群间的遗传分化,再次,遗传漂变也是另一重要影响因素;此外,适应性进化亦可能加剧了居群间的遗传分化,而基因流对遗传分化的影响不大。     

秦岭山区美容杜鹃五个野生种群遗传多样性的ISSR分析

美容杜鹃是杜鹃花科杜鹃花属常绿观花植物,也是秦岭地区的特有属,在维持当地生态平衡方面发挥着重要作用,但目前资源正在遭受严重的破坏。该文通过ISSR分子标记技术对秦岭地区5个美容杜鹃野生种群进行遗传多样性分析,了解美容杜鹃不同种群的遗传分化,从而为美容杜鹃野生种质资源保护策略的制定提供理论依据。用8个ISSR引物对5个天然种群的90个单株进行扩增,共扩增出78条带(平均每条引物产生9.75条带),其中65条带是多态的,多态位点占总位点的百分率为83%。种群总的Nei’s基因多样性指数为0.3386,Shannon信息多态性指数为0.4972,表明美容杜鹃总的遗传多样性水平较高。种群多态位点百分率为82.71%~90.25%,Shannon信息多态性指数为0.4161~0.5867,Nei’s基因多样性指数为0.3044~0.4122,表明美容杜鹃不同种群遗传多样性水平差异较大。其中镇安木王种群和柞水牛背梁种群的遗传多样性水平较高。AMOVA分析表明种群内的遗传变异(91.22%)大于种群间的遗传变异(8.78%)。UPGMA聚类分析表明5个种群的遗传分化程度与地理距离没有相关性。因此建议尽可能地保护美容杜鹃所有的天然种群原生境条件,以最大限度保护其遗传变异。由于镇安和柞水种群具有较高的遗传多样性,因此建议优先对这2个种群实施就地保护和迁地保护。     

不同海拔高度木荷种群遗传多样性的ISSR分析

利用ISSR分子标记技术分析了浙江天台山不同海拔高度木荷种群的遗传多样性和遗传分化.用12个引物对4个木荷种群共80个样品进行扩增,共检测到170个位点,其中多态位点154个,多态位点百分率(P)为90.59%.木荷总的Shannon信息指数(I)为0.5033,Nei指数(h)为0.3408,表明种水平的遗传多样性较高.而种群水平的遗传多样性比种水平低,P平均为63.68%,I平均为0.3789,h平均为0.2608.AMOVA分子差异分析表明,在总的遗传变异中,29.56%的变异存在于种群间,70.44%的变异存在于种群内,种群间的基因分化系数(Gst)为0.2348.木荷种群间的基因流为1.6293,4个种群间的平均遗传距离为0.1500.     

在韩国境内Potentilla fragarioides var .sprengeliana的遗传多样性和种群结构(英文)

根据 2 2个等位酶位点遗传变异 ,探讨了韩国境内委陵菜 (PotentillafragarioidesL .var.sprengeliana)的遗传多样性和种群结构。酶位点的多态位点百分比为 5 9 1%。种和种群水平上的遗传多样性比较高 ,分别为Hes=0 .2 10 ,Hep=0 .199;而种群的分化水平则相对较低 (GST=0 .0 74)。 19个种群中随机交配的偏差为FIS=0 .331。每代迁移数的间接估计 (Nm=3.15 )表明该种在韩国的种群间基因流较高。另外 ,固定指数分析显示在一些种群和位点有轻微的杂合子缺乏。种群间平均遗传一致度为 0 985。这些韩国委陵菜种群存在于较为均一的生境 ,这很有可能是造成其种群遗传一致性较高的原因。     

西藏特有植物砂生槐天然居群遗传多样性研究

采用等位酶淀粉凝胶电泳技术对西藏雅鲁藏布江中游砂生槐 (Sophoramoorcroftiana) 10个天然居群的遗传多样性进行了研究。 13个酶系统 2 4个酶位点 ( 46个等位基因 )的检测结果表明 ,砂生槐具较低的遗传变异水平。居群水平上的遗传多样性指标分别为 :多态位点百分率Pp =2 5 .0 %～ 37.5 % ,等位基因平均数Ap=1.3～ 1.7,平均期望杂合度Hep=0 .112～ 0 .16 9;种水平上的遗传多样性 (Ps=37.5 % ,As=1.9,Hes=0 .171)低于长寿命木本被子植物的平均值 (Ps=5 9.5 % ,As=2 .10 ,Hes=0 .183)。居群遗传结构的分析显示 ,10个居群中随机交配的偏差为FIS=- 0 .0 0 71,表明砂生槐在居群水平上存在轻微的杂合子过量现象 ,偏离了Hardy Weinberg平衡 ;FST=0 .1748,表明砂生槐是居群间分化较大的一类多年生木本植物 ,主要原因是环境恶化和人类活动干扰 (过度砍伐、放牧等 )导致其生境片断化 ,从而影响了居群间基因交流而造成基因流水平较低 (Nm =1.180 2 )。砂生槐高海拔居群H2 (谢通门 )、H31(江当 1)、H32 (江当 2 )、H5 (朗塞岭 )包含着绝大部分等位基因 ,显示了相对较高的遗传多样性水平 ,应加以保护和管理 ,作为砂生槐种质资源就地保存的基地。     

药用植物天麻（Gastrodia elata Bl.）的等位酶遗传变异及其变型间的遗传关系

采用超薄平板聚丙烯酰胺等电聚焦电泳,对湖北西部药用植物天麻（Gastrodia elata Bl.）的4种变型进行了等位酶遗传变异的初步分析。在6个酶系统共检测到17个清晰位点和37个等位基因,其中多态位点11个,位点最大等位基因数为4,位点Acp-4和Prx-2的等位基因表现出变型特异性。遗传多样性分析结果表明：天麻在物种水平维持着较高遗传多样性,平均多态位点比率P=56.3%,每位点平均等位基因数A=2.1,平均预期杂合度He=0.222;但其变型水平遗传多样性较低（P=42.2%,A=1.7,He=0.146）,其中乌天麻遗传多样性最高,药天麻最低。天麻变型间遗传分化系数（GST）达0.3595,平均基因流（Nm）仅为0.4450,说明天麻变型间遗传分化较大,缺乏基因交流。聚类分析结果表明,天麻居群以变型为单元优先聚类而非地域优先聚类,揭示各天麻变型在遗传上是相对独立的进化显著单元,支持天麻种内变型的划分。红天麻与乌天麻两变型最为近缘,火天麻与药天麻两类群有着较近的遗传关系。     

高原鼠兔四个地理种群的遗传多样性与遗传分化

采用7 个多态微卫星DNA 标记分析了4 个高原鼠兔地理种群(海晏种群、西大滩东种群、西大滩西种群和昆仑山种群)的遗传多样性和遗传分化。采用多态信息含量(PIC)、期望杂合度(H_e )、观测杂合度(H_o)、基因流(N_m )和基因分化系数(F_st )对种群及物种的遗传多样性水平进行分析;计算各种群间的遗传距离(GD)、遗传相似度(GI)以及遗传距离与地理距离的相关系数,并进行UPGMA 聚类分析。研究结果显示,高原鼠兔的遗传多样性在小哺乳动物中处于较高水平, 其H_e 和H_o 的平均值分别为0. 5332 和0. 6003, 其F_st 为0. 0975,即有9. 75% 的变异存在于种群之间,即变异主要存在于种群内部。4 个种群间的杂合度与多态信息含量均无显著差异,说明它们的遗传多样性水平基本相当。海晏种群与其余3 个种群的遗传分化均达到了中度分化水平(F_st = 0.1043),而另3 个种群间几乎没有分化(F_st = 0. 0253)。Mantel test 结果表明地理距离与遗传距离间没有显著的相关性。     

山西省8种蝗虫8个种群的遗传学研究

采用水平淀粉凝胶电泳技术,对采自山西省蝗虫区系的优势种类;斑腿蝗科（Catantopidae）,斑翅蝗科（Oe-dipodidae）和网翅蝗科（Arcypteridae）3科7属8种蝗虫的11种酶进行了检测,共辨析出17个酶基因座位,并计算出等位基因频率和遗传距离,等位基因频率分析表明：Ao-I、Est-3,G3pd-1、Idh-2和Mdh-2基因座位的等位基因少,等位基因数目在种间变化较小,故推断其进化速率较慢,利用这些基因座位的保守特征,可作为分子标记研究较高级阶元的系统发育关系,而Gpi-1,Ldh-1和Me-1基因座位的等位基因多,等位基因数目在种内和种间差异较大,可以用作种,属间及种群间遗传结构的比较研究。对每个基因座位的各基因型进行χ^2检验,除Acp-1,Adk-1,Ao-1和Ao-2在部分蝗虫中符合Hardy-Weinberg平衡外,其余绝大多数基因座位的基因型频率显著偏离H-W平衡。在所研究的8种蝗虫中,多态位点百分率普遍较高（P=64.7%～94.1%）,但由于杂合子数目较少而使每个基因座位的平均杂合度降低（Ho=0.024～0.087）,对多态位点百分率分析发现：迁飞能力是影响蝗虫种间遗传变异的因素之一,具有迁飞能力的蝗虫（P=88.2%～94.1%）较非迁飞性蝗虫（P=64.7%～94.1%）表现出较高的遗传多态性,但也有例外,如中华稻蝗（Oxya chinensis）的P值高达94.1%,上述结果表明：由于迁飞行为可使个体暴露于各种不同环境,故而种群保持较高的遗传多态性能增强该物种在不同栖息地的生存和繁殖能力,因此,迁飞有利于维持迁飞性蝗虫遗传多态性的动态平衡。根据Nei的遗传一致度（I）和Roger的遗传距离（D）进行分析,结果与基于形态特征确定的分类阶元系统关系基本相符;即同属的小翅雏蝗（Chorthippus fallax）和白纹雏蝗（Chorthippus albonemus）具有最高的遗传一致度（I=0.813）和最小的遗传距离（D=0.336）,同位不同属间遗传一致度（I=0.798～0.559）和遗传距离（D=0.398～0.474）居中,科之间I值最小（I=0.523～0.479）,D值最大（D=0.505～0.523）,利用UPGMA对I值和D值进行聚类,所得两种聚类图在同属种间和同科属间的关系一致,但在科间关系有所差别,Roger的遗传距离（D）聚类树图表明：斑腿蝗科物种和斑翅蝗科物种间表现出较小的遗传距离（D=0.505）,而网翅蝗科与以上两科的遗传距离也极为接近（D=0.523）,综上所述,等位酶分析能较好地反映蝗虫同属种间和同科属间的亲缘关系,若能断更高阶元的系统发生,则需结合其他性状进行综合分析。     

Microsatellite variation within and among populations of Oryza officinalis (Poaceae), an endangered wild rice from China

Oryza officinalis Wall. ex Watt. is an agriculturally important but seriously endangered species of wild rice. To obtain more accurate estimates of population structure for improved conservation planning of the species, genetic variability at 14 microsatellite DNA loci was examined in population samples covering most of the species' range in China. Considerable genetic variability (overall Na = 1.886, P = 62%, HO = 0.056, HE = 0.216, and HS = 0.277) was detected at the 14 loci in 442 individuals of the 18 natural populations. The evaluation of partitioning of genetic variability (FST = 0.442) suggested high genetic differentiation among the Chinese O. officinalis populations. An overall value of Nm = 0.316 suggested limited gene flow occurred among the sampled populations. Most of the populations showed heterozygote deficits in tests of Hardy-Weinberg equilibrium and significantly positive FIS values. This could be due to some inbreeding occurring in this predominantly outcrossing species. For effective in situ conservation and restoration genetics, maintenance of significant historical processes is particularly important, including high outbreeding, considerable gene flow, and large population effective sizes. The high FST values detected among populations in this study are instructive for adopting a conservation plan that includes representative populations with the greatest genetic variation for either in situ conservation management or germplasm collection expeditions.     

First Report on RAPDs Patterns Able to Differentiate Some Argentinean Species of Section Algarobia (Prosopis, Leguminosae)

Prosopis species constitute a very important resource in arid and semiarid regions. Some species of section Algarobia hybridise and introgress naturally in areas of sympatry. According to previous isoenzymatic studies these species have high variability within populations. However, the genetic differentiation among species was very low, and these markers failed to provide diagnostic loci for species recognition. Here we analysed by the RAPD technique natural populations of Prosopis alba, P. ruscifolia, P. nigra, P. flexuosa, and P. vinalillo with the purpose of obtaining markers for species and hybrid identification, by analysing the distribution of genetic diversity within and among species. Genetic variability (H = 0.12-0.26) was similar in all populations. Genetic differentiation among populations (FST = 0.39) was highly significant. Hierarchical analysis of genetic structure performed by Wright (1978) method and analysis of molecular variance (AMOVA) indicated that the diversity among populations within species is low (4-13%) and most genetic diversity (54-61%) occurs within populations. The differentiation among species is intermediate (26-42%) between the previous components but highly significant. Five bands provided a tool for identifying any of the species studied, with the exception of P. vinalillo. The difficulty in diagnosing this species is discussed in reference to the hypothesis of its hybrid origin.     

山东省长岛县南部四岛藜（Chenopodium album L.）天然种群遗传多样性的ISSR分析

采用ISSR分子标记对分布于山东省长岛县南部的北长山、南长山、大黑山和小黑山4个岛屿上的藜天然种群共81个个体进行了遗传多样性及遗传结构的研究。13个引物共检测到157个可重复的位点。遗传多样性研究结果表明：种内的多态位点比率为66.24％,具有较高的遗传多样性（Shannon（I）指数在物种水平上为0.332 0）;种群间有一定的遗传分化,根据G_st值,种群间的遗传多样性占总群体的9.27％。遗传距离分析表明,XHS种群和NCS种群的遗传一致度最高,与地理距离无相关性。     

Genetic diversity and genetic relationship of Caragana microphylla, Caragana davazamcii and Caragana korshinskii on the Inner Mongolia Plateau, China

C. microphylla, C. davazamcii and C. korshinskii exhibit a geographical replacement series from east to west on the Inner Mongolia Plateau. Currently, there is still a debate about the taxonomic and genetic relationship among these 3 species. We studied the genetic diversity and genetic relationship among these 3 species by analyzing DNA samples of individual plants from within 10 populations with random amplified polymorphic DNA (RAPD) markers. We identified 678 RAPD loci in total, of which all were polymorphic (PPB = 100%). There were 41 unique loci (6.05%). In general, a trend presented that the genetic diversity of these species decreased from east to west. Further, the genetic diversity was significantly negatively correlated with the local annual mean temperature. Analysis of molecular variation (AMOVA) showed that the genetic variation among these 3 species was only 6.08% of the total genetic variation. Between the species, the genetic variation was insignificant (P = 0.9961). The proportion of genetic variation among populations within each species was 11.90% (P < 0.001) of the total genetic variation, and the total genetic variation mainly existed within the populations (82.02%). Estimated with Shannon's index, genetic differentiation within the populations (Hpop/Hsp) was 0.8013, the coefficient of gene differentiation (Gst) was 0.1603, and the gene flow index (Nm) was 2.6192. This, thus, indicates that there is relatively high gene flow among these populations, and that these 3 species are crossbreeding. The genetic diversity level and the population distribution pattern showed geographic continuity to some extent.     

中国东亚飞蝗两个种群遗传分化的研究

采用水平淀粉凝胶电泳技术,分析了我国河北平山、辽宁葫芦岛两个蝗区东亚飞蝗自然种群的遗传结构。在酶谱分析的19个位点中,多数位点的等位基因数目较少,而位点Aat—l、Pgi和Mdh—2的等位基因数目相对较多。由于杂合子数目较少而使每个基因位点的平均杂合度降低(Ho=0．024和0．028)。对每个位点的各基因型进行x^2检验,绝大多数位点的基因型频率偏离Hardy—Weinberg平衡。较低的Fst值(Fst=0．021)表明两个种群的遗传分化程度不高。两个种群间较高的遗传一致度(I=0．991)和较小的遗传距离(D=0．092)也证实了上述结果。由此推测,该蝗虫较强的迁飞能力有可能增强种群间的基因交流,降低种群间的遗传分化。然而,在一些等位酶指标如位点Ao-2、Fbp—l、Mdh—2的等位基因频率分布、每个位点的平均等位基因数(A=2．5和2．7)和多态位点百分率(P=52．6％和57．9％)等,两个种群之间呈现出明显的差异。这也许与两个种群之间不同的生态环境条件和较远的地理距离有关。     

Gene diversity analysis in natural populations and cultured stocks of turbot (Scophthalmus maximus L.)

The genetic variability of eight fish-farm and three natural populations of turbot was studied by electrophoretic analysis of 35 enzymatic loci. The results showed low genetic variability in natural populations of turbot ( H _T = 0·029 ± 0·013) in comparison with other flatfish species. Great genetic similarity was revealed among the natural populations studied, which indicates high rates of gene flow in this species. The hatchery stocks showed less genetic variation than the wild populations analysed, which suggests genetic drift phenomena involved in the foundation and management of broodstocks. In addition, the heterozygosity differences detected among the hatchery stocks analysed are correlated with inverted levels of fluctuating asymmetry, which supports the existence of inbreeding depression phenomena in turbot culture.     

A study on population genetic structure of Oryza meyeriana (Zoll. et Mor. ex Steud.) Baill. from Yunnan and its in situ conservation significance

In order to determine genetic diversity of Oryza meyeriana (Zoll. et Mor. ex Steud. ) Baill., 12 enzyme systems encoded by 17 loci were electrophoretically analyzed in 164 individuals of seven populations from Simao Prefecture, Yunnan Province, China. In comparison with those seed plants with the same life history and breeding systems, as well as the other species in the genus Oryza, the species shows rather low levels of genetic diversity (A = 1.1, P = 8.0%, Ho = 0.004 and He = 0. 015) within populations and high genetic differentiation among populations. FST was up to 0. 649, suggesting that 64. 9% of total genetic variability exists among populations. Considering high genetic differentiation among populations from a limited geographic region, most of the populations of the species are worth being protected, and therefore, great natural protection regions should theoretically be established in which a great deal of populations should be involved for developing in situ conservation management. Meanwhile     

Spatial genetic structure and clonal diversity of island populations of lady's slipper (Cypripedium calceolus) from the Biebrza National Park (northeast Poland)

Three populations of the rare and endangered plant species Cypripedium calceolus were included in a study of genetic diversity and spatial genetic structure in the Biebrza National Park, northeast Poland. Analysis of 11 allozyme loci indicate that the populations of this species contained high genetic variability (P = 45.5%, A= 1.73). On the other hand, the genetic differentiation (FST = 0.014, P < 0.05) among C. calceolus populations was very low when compared to other species with similar life history characteristics. The observed high rate of gene flow (Nm = 18) may suggest that the populations studied derived from each other in the recent past. Five polymorphic allozyme markers identified 109 multilocus genotypes in three populations and the majority of them (67%) were population-specific. One of the populations studied, characterized by particularly extensive vegetative reproduction, showed the lowest clonal diversity (G/N = 0.15) and heterozygosity (HO = 0.111) values and the highest FIS(0.380), when compared to other two populations (G/N = 0.26-0.27, HO= 0.166-178, FIS = 0.024-0.055). This may indicate that clonal reproduction has an important influence on the genetic structure of C. calceolus populations. The longevity of genets, the out-crossing breeding system and the presence of recruitment from seeds are factors maintaining genetic diversity in C. calceolus.     

栌菊木的等位酶分析及其在生物地理和保护生物学上的意义

对我国西南特有的菊科单种属植物栌菊木10个居群、149个个体、11个酶系统及16个酶位点的水平淀粉凝胶电泳分析表明,栌菊木的遗传多样性水平在特有种中较高,在居群水平上,平均每个位点的等位基因数A=1．1—1．4,多态位点百分数P=6．3％—43．8％,实际杂合度Ho=0．063～0．250,期望杂合度He=0．043～0．194;物种水平上A=1．6,P=37．5％,Ho=0．143,He=0．141。居群间遗传一致度I=0．902—1．000,杂合性基因多样度比率FST为0．2395。栌菊木居群间分化程度较大,云南南盘江流域碧云寺居群遗传多样性较低,明显低于金沙江流域的居群。栌菊木可能是来自冈瓦纳古陆祖先的后裔,可能是古地中海退却以后在金沙江干热河谷分化出来的特有属,并且可能由于湿度等生态因子的限制,其分布区未能进一步扩大,仅在南盘江流域形成零散分布。等位酶分析结果还表明栌菊木遗传多样性总体水平较高,建议对遗传多样性较高的金沙江流域的居群加以保护。