应用微卫星标记研究西藏野生大麦的遗传多样性

以西藏不同地区的106份野生大麦为材料,其中包括50份野生二棱大麦（HS）,27份野生瓶形大麦（HL）和29份野生六棱大麦（HA）,用Liu等（1996）发表的SSR连锁图的每个连锁群的两个臂的不同位置上选取3～5个共30个SSR标记,研究了西藏3类野生大麦的遗传多样性。结果表明,这3类野生大麦在遗传组成及等位变异频率分布上存在着明显的遗传分化。在总样本中,共检测到229个等位变异,平均每个SSR位点检测到7．6个等位变异,其中70个为这3类野生大麦间共同的等位变异,等位变异数在这3类野生大麦间有明显的差异,亚种问的遗传多样性明显高于亚种内的遗传多样性。其遗传多样性大小顺序为HS〉HL〉HA。聚类分析表明,野生二棱大麦、野生六棱大麦分别聚在不同的两类,而野生瓶形大麦中各有约50％的材料分别聚在这两类。根据本研究及前人研究结果,我们认为中国栽培大麦是从野生二棱大麦经野生瓶形大麦向野生六棱大麦进化的。该结果支持了栽培大麦起源的“野生二棱大麦单系起源论”的观点。     

云南保存橡胶树部分种质资源干形及分枝变异分析

对保存于"农业部景洪橡胶树种质资源圃"的1904份橡胶树81’IRRDB种质资源的主干通直度、主干分杈、侧枝分枝轮、侧枝粗细、侧枝分枝角、侧枝伸展等6个表型性状进行调查和分析。结果表明,云南保存橡胶树种质资源具有丰富的遗传多样性(0.2604~1.6731),多样性指数最高的是主干通直度,达1.6731,其次是主干分杈、侧枝粗细、侧枝分枝轮和侧枝分枝角,最低的是侧枝伸展。6个表型性状的相对分布频率最小值为2.92%~8.05%,最大值为41.26%~93.37%。用UPGMA法聚类,当欧式距离为1.05时,1904份样本被聚为5组,其中最大1组包括98.42%的样本,表明同一性状在每份种质资源间具有很大程度的相似性;用Furthest Neighbor法聚类,在欧式距离为1.45时,1904份样本被聚为7组。2种聚类方法都能将每份种质明显区分出来,表明各性状变异极其丰富。     

巨龙竹笋-幼竹期秆形发育的组织解剖学研究

巨龙竹( Dendrocalamus sinicus Chia et J. L. Sun)是云南特有的珍稀木本丛生竹,其秆形分为通直型和弯曲型两种变型。为了揭示巨龙竹不同秆形的组织结构特征,本文通过定点观测0 ~ 49 d的巨龙竹笋和幼竹生长发育状况,并采用石蜡切片技术对笋期0 ~ 45 d内样品的组织结构进行比较解剖学研究。结果显示:(1)巨龙竹在笋-幼竹(0 ~ 49 d)发育期,秆高生长呈“慢-快”的趋势,21 ~ 35 d时弯曲型茎秆开始显现,易于辨别;(2)5 ~ 30 d时,弯曲型茎秆中维管束的发育早于通直型;对比弯曲型茎秆内外两侧维管束,内侧维管束导管内径较小,但纤维鞘中的纤维细胞层数更多;(3)弯曲型茎秆中薄壁细胞的分化早于通直型,20 d后弯曲型茎秆中的薄壁细胞出现明显的可被番红-固绿染色的细胞核,并呈有规律的排列;弯曲型茎秆内侧薄壁细胞稍小于外侧薄壁细胞,但内侧被染色细胞核的薄壁细胞多于外侧。研究结果表明巨龙竹弯曲型茎秆性状在笋期第21 ~ 35 d内即可通过茎秆形态判别,弯曲型茎秆中维管束的发育以及薄壁细胞分化均早于通直型茎秆,同一时期弯曲型茎秆内侧细胞分裂较外侧旺盛、维管束木质化程度更高。     

亚欧美栗疫病菌群体的遗传多样性

从 12 0个随机引物中筛选出条带清晰、主带明显、重复性好的 9个引物 ,对来自不同地域和寄主的 7个群体的 14 2个栗疫病菌菌株进行 RAPD分析。 9个引物共扩增出条带 12 4条 ,其中多态性条带 111条 ,多态性比率为 89.5 2 %。利用 Popgen3.2软件对供试群体进行遗传多样性分析和 UPGMA聚类。结果表明 ,中国地区 4个群体间的遗传相似性较大 ,与美国、意大利和日本群体间的相似性较小 ;美国和意大利群体间的遗传相似性较大 ,且它们与日本群体间的相似性大于与中国群体间的相似性。病原菌群体的遗传变异率为 0 .2 35 1,其中在地区水平上 ,82 .34%由群体内的变异引起 ,17.6 6 %由群体间的差异引起 ,群体间的基因流动值为 2 .3311;而在寄主水平上 ,则 79.4 2 %由群体内的变异引起 ,2 0 .5 8%由群体间的差异引起 ,群体间的基因流动值为 1.92 97     

锐药竹的种子性状及分子遗传变异

锐药竹( Oxytenanthera abyssinica)是非洲竹区最重要的竹种,对当地民众生活、生产和环保具有重要作用,也是保护当地环境的重要组成成分。然而,对这样重要的竹种,非洲内、外均少见其遗传研究报道。该研究对采自埃塞俄比亚的同一居群锐药竹少见的开花结实种子,采用“林木种子检验规程”国家标准,测定种子的主要性状,并对其遗传品质进行了分析。结果表明：锐药竹的种子长度为18.2 mm,宽度为3.3 mm,千粒重为117.5 g,室内发芽率为66.5％。性状变异与其他竹类相近,变异不大。将这批种子育苗15000多株,随机选择39株,典型选择25个叶片大的植株,共64个单株,采集叶样,运用扩增片段长度多态性( AFLP )分子标记技术进行遗传多样性检测。筛选E-ACA/M-CAA等8对引物对样品经行扩增,电泳分离,利用GeneScan 3.1软件共统计到1728条谱带,计算出其多态位点百分率90.28％,Nei’ s基因多样性指数0.2463,Shannon多样性指数0.3623,为遗传多样性大的类型;采用单匹配相似系数法对样品谱带进行UPGMA聚类,取SM＝0.76,可将分析样品聚为3类,结合表型进一步进行种质挖掘研究。该研究结果为其生物多样性保育及选育优良品种提供了科学依据。     

辽东湾斑海豹遗传多样性的AFLP分析

利用AFLP标记技术对辽东湾斑海豹的遗传多样性进行分析。采用7对AFLP引物对斑海豹3个群体(按不同采样年份分类)43个个体扩增共得到241个位点,3个群体内的多态位点比例为80.45%～95.85%,总多态位点比例为99.59%。群体的香农(Shannon)多样性指数为0.3817～0.4716,群体间的遗传距离在0.1742～0.4023之间。2007年群体的多态位点比例、Shannon多样性指数均高于2006年群体,2005年群体处于中等水平。用NTSYS软件进行个体聚类及UPGMA方法构建的群体系统树,发现3个群体的个体基本随机聚到一起,界限不十分明显,说明3年的群体差异不明显,甚至可以认为它们是混合群体。结果表明,斑海豹群体遗传多样性水平较低,遗传结构趋于简单化,且存在较强的基因交流。     

巨龙竹笋-幼竹期秆形发育的组织解剖学研究

巨龙竹（Dendrocalamus sinicus Chia et J.L.Sun）是云南特有的珍稀木本丛生竹,其秆形分为通直型和弯曲型两种变型。为了揭示巨龙竹不同秆形的组织结构特征,本文通过定点观测0~49 d的巨龙竹笋和幼竹生长发育状况,并采用石蜡切片技术对笋期0~45 d内样品的组织结构进行比较解剖学研究。结果显示：（1）巨龙竹在笋-幼竹（0~49 d）发育期,秆高生长呈"慢-快"的趋势,21~35 d时弯曲型茎秆开始显现,易于辨别;（2）5~30 d时,弯曲型茎秆中维管束的发育早于通直型;对比弯曲型茎秆内外两侧维管束,内侧维管束导管内径较小,但纤维鞘中的纤维细胞层数更多;（3）弯曲型茎秆中薄壁细胞的分化早于通直型,20 d后弯曲型茎秆中的薄壁细胞出现明显的可被番红-固绿染色的细胞核,并呈有规律的排列;弯曲型茎秆内侧薄壁细胞稍小于外侧薄壁细胞,但内侧被染色细胞核的薄壁细胞多于外侧。研究结果表明巨龙竹弯曲型茎秆性状在笋期第21~35 d内即可通过茎秆形态判别,弯曲型茎秆中维管束的发育以及薄壁细胞分化均早于通直型茎秆,同一时期弯曲型茎秆内侧细胞分裂较外侧旺盛、维管束木质化程度更高。     

青藏高原青稞品种醇溶蛋白的遗传多样性

利用A-PAGE（acid-polyacrylamide gel electrophoresis）法对来自中国青藏高原地区67份青稞品种进行了醇溶蛋白位点的遗传多样性研究。共分离出29条相对迁移率不同的条带,多态性为100％。所有材料在Ⅰ、Ⅱ和Ⅲ醇溶蛋白位点分别发现了36、46和7种等位变异类型,总变异数以四川材料为最高,甘肃材料为最少,等位变异类型频率在地区间的分布存在显著或极显著差异。4个青稞群体醇溶蛋白Ⅰ、Ⅱ位点的遗传多样性均略大于Ⅲ位点的遗传多样性,4个地区材料的平均遗传多样性无显著性差异。聚类分析结果表明,67份材料可分成A、B、C、D、E、F、G和H8类,材料聚类与其生长的地区有明显的相关性。     

利用线粒体COI和微卫星标记分析文蛤7个地理群体的遗传变异

利用线粒体细胞色素氧化酶亚基I(COI)和微卫星标记分析了文蛤7个地理群体(朝鲜新义州,辽宁丹东、蛤蜊岗和盘山,山东东营,江苏如东和启东)的遗传多样性和群体分化。PCR扩增获得142条602 bp的COI核苷酸片段,比对到13个变异位点,包括11个转换和2个颠换,定义了22个单倍型,共享单倍型12个,新义州、丹东和启东群体分别拥有特有单倍型。单倍型多样性最高的是如东群体(h=0.900),最低的是东营群体(h=0.600);核苷酸多样性最高的是丹东群体(π=0.00350),最低的是蛤蜊岗群体(π=0.00115)。基于COI数据的Fu's Fs中性检验和核苷酸不配对分析揭示文蛤种群历史上曾经历过群体扩张事件。分子变异分析(AMOVA)表明,群体内遗传变异占71.64%,群体间遗传变异占28.36%,群体间发生显著的遗传分化(P0.05)。7个微卫星标记扩增280个个体共获得54个等位基因,平均等位基因数为7.7个,平均观测杂合度和期望杂合度分别为0.3878和0.7996。江苏群体具有较高的遗传多样性,但7个群体间遗传多样性不存在显著差异(Kruskal-Wallis检验,P0.05)。Hardy-Weinberg平衡检验结果显示49个群体-位点组合中有18个偏离平衡(P0.05),表现为杂合子缺失。单倍型邻接(NJ)树显示聚类未展示地域性特色,但某几个同一或者相近地理群体的单倍型具有聚类现象(如东和启东部分单倍型出现地理聚类)。依据群体间遗传距离以Kimura 2-parameter为模型建立UPGMA系统发育树,显示丹东群体和江苏的如东和启东群体聚为一支,暗示江苏苗种的异地养殖已经污染丹东文蛤的遗传背景。     

广东5个野生大豆居群的遗传多样性分析

采用SSR分子标记对来自广东省5个县野生大豆居群的遗传多样性进行了分析,为广东野生大豆资源保护和利用提供依据。结果显示:(1)5个野生大豆居群在60个SSR位点共检测出263个等位变异,同一位点上等位基因数目最多为10个,最少为2个,平均为4.38个;不同群体中特有等位基因数不同,其中连州(LZ)和南雄(NX)野生大豆的特有等位基因数目较多,分别为19个和16个;Shannon指数(I)变化范围为0.162~2.174,期望杂合度(He)的变化范围为0.073~0.899。(2)广东连州(LZ)野生大豆居群的遗传多样性最高,而仁化(RH)野生大豆的遗传多样性最低,二者的Shannon指数(I)分别为0.811、0.113;群体分子方差(AMOVA)分析结果揭示,居群间变异占51%,群体内变异占49%,且仁化居群与其他居群间基因流较小。(3)依据遗传距离可将连州(LZ)和连南(LN)聚类为一类,乳源(RY)和南雄(NX)为一类,仁化(RH)单独为一类。研究表明,广东不同野生大豆居群间遗传多样性差异较大,而且居群内基因类型多,其中连州(LZ)和乳源(RY)野生大豆居群的遗传多样性较高,证明广东野生大豆群体保存了丰富的基因资源。     

中国南方茶棍蓟马地理种群遗传分化分析

【目的】基于mtDNA COI和COⅡ的联合序列,探讨中国南方茶棍蓟马Dendrothrips minowai地理种群的遗传多样性与遗传分化。【方法】利用MEGA 6.0, DnaSP 5.10和Arlequin 3.5.2.2等软件对中国南方茶棍蓟马8个地理种群遗传多样性、遗传分化、基因流、分子变异及地理距离与遗传距离的相关性进行分析,并推断群体演化历史。【结果】茶棍蓟马mtDNA COI和COⅡ序列均具有明显的AT偏好性,COI和COⅡ联合序列的长度为1 146 bp,共有22个单倍型。中国南方茶棍蓟马总群体遗传多样性较高,表现出高单倍型多样性(Hd=0.924)和低核苷酸多样性(π=0.00600)。8个地理种群总群体的遗传分化程度高(F_ST=0.84830),基因交流水平低(Nm=0.040),群体可能由于遗传漂变而发生明显分化。AMOVA分析显示,茶棍蓟马种群的遗传变异主要来自组间种群(F_CT=0.84922);Mantel检测显示地理距离与遗传距离存在显著的正相关(r=0.5029, P<0.01)。中性检验结果表明,除云南两个地理种群外的其他地理种群近期可能经历了种群扩张。【结论】中国南方茶棍蓟马地理种群遗传多样性较高,具有明显的遗传分化,基因交流较少;地理距离可能是影响茶棍蓟马地理种群遗传分化的主要因素之一。     

Social and genetic characteristics of geographically isolated populations in the ant Formica cinerea

The ant Formica cinerea in northern Europe has geographically isolated populations that were examined using five microsatellite loci. The populations differ widely regarding the social organization of colonies. Based on genetic relatedness (r) among worker nest mates, the populations were classified as M type with monogynous (single queen) colonies (r > 0.59), as P type with polygynous colonial networks (r < 0.1), or as intermediate with weakly polygynous colonies (0.16 < r < 0.47). The social types showed weak geographical clustering, but the overall distribution indicated that the shift between the social types has occurred several times. The geographically isolated populations had slightly reduced levels of genetic diversity compared to populations from areas where the species is abundant and continuously distributed. Many of the isolated populations consisted of monogynous or weakly polygynous colonies, making their effective population sizes small, and some of them also showed weak bottleneck effects. The overall level of microsatellite diversity within populations was relatively high and differentiation among populations low, indicating recent connections. Isolation of populations may thus be a new phenomenon resulting from reduction of suitable habitats. At the local level, we obtained limited support from a group of nearby subpopulations in southern Finland to the hypothesis that the P type is connected to restricted dispersal. Other P type populations did not, however, show similar elevated levels of differentiation.     

用扩增片段的长度多态性分子标记探讨盾叶薯蓣的遗传多样性

用扩增片段的长度多态性(amplified fragment length polymorphism,AFLP)标记分析研究了中国5个盾叶薯蓣居群30个个体的遗传多样性。筛选出9对AFLP引物,从中检测到14698条清晰可见的条带,其中多态性带12628条,多态性比率85.92%。Shannon信息指数(I)为0.3656±0.1721,物种水平的Nei基因多样性(H)为0.2322±0.2200。遗传变异分析表明,物种水平的遗传分化系数Gst为0.4827,说明其群体间存在一定的遗传分化,居群间的基因流Nm为0.5358,居群间遗传交换较小。聚类分析结果显示5个居群盾叶薯蓣有较为丰富的遗传变异,且与地理分布有相关性。     

附子野生资源群体遗传多样性的RAPD分析

应用RAPD标记分析了分布在附子主栽区四川、重庆、陕西及湖北16个野生乌头种群的遗传变异。24个引物共检测到643个RAPD位点,多态位点602个,总的多态位点百分率达93．5％。Shannon多样性和Nei遗传分化结果一致显示重庆酉阳种群和重庆城口种群遗传多样性最高,四川盐源种群和陕西勉县种群的遗传多样性最低。Shannon指数测出的种群内的遗传变异（57．6％）略占优势,群体间的遗传分化达到42．4％;Nei基因分化系数（GST）达40．0％;分子方差分析（AMOVA）发现群体间遗传变异仅为25．37％;种群每代迁移数Nm为0．756。Nei相似性系数的UPGMA分析结果显示该地区的野生乌头分布上有一定的地域性,特别是同为附子道地产地江油供种的北川、安县和青川种群间遗传关系密切,说明种质资源在道地药材形成中具有重要作用。研究结果表明,附子主要栽培地区的乌头野生种群之间存在较大的遗传分化,遗传多样性较高,遗传种质资源较丰富,存在一定的特异性资源,为进一步开发利用乌头（川乌、附子）提供了丰富的种质资源。     

斑衣蜡蝉若虫寄生蜂地理种群遗传差异及早期快速检测

【目的】明确不同地理种群斑衣蜡蝉Lycorma delicatula若虫寄生蜂种群遗传差异,实现若虫被寄生早期的快速准确检测,以评估其对斑衣蜡蝉种群的控制作用。【方法】利用DNA条形码技术获得不同地理种群斑衣蜡蝉若虫寄生蜂COI和28S rDNA序列,利用K2P模型计算不同地理种群间的遗传距离,以邻接(neighbor-joining,NJ)法构建系统发育树;基于COI序列设计种特异性PCR(SS-PCR)引物,利用SS-PCR对斑衣蜡蝉若虫DNA进行扩增,测定其体内是否有中华螯蜂Dryinus sinicus寄生;利用目测法观察和PCR扩增测定寄生蜂对不同采样点斑衣蜡蝉若虫的寄生率。【结果】经鉴定,不同地理种群斑衣蜡蝉若虫寄生蜂为中华螯蜂,该寄生蜂COI序列共检测到16个单倍型,28S rDNA序列共检测到4个单倍型。不同地理种群间中华螯蜂遗传距离在0.00691~0.01310之间。邻接法构建的系统发育树显示不同地理种群中华螯蜂均聚于一枝。基于COI序列设计的SS-PCR引物对中华螯蜂成虫、幼虫均具有良好的扩增效果,最低检测阈值为0.000005 ng/μL DNA。利用SS-PCR测定中华螯蜂对各采样点斑衣蜡蝉若虫的寄生率为22.54%~60.00%,显著高于目测统计的结果(5.63%~36.98%)。【结论】不同中华螯蜂地理种群间遗传差异较小;SS-PCR引物可用于不同地区中华螯蜂对斑衣蜡蝉早期寄生率的快速检测。     

不同地区库蚊复组群体的同工酶遗传多样性研究

采用水平切片淀粉凝胶电泳的方法,对分布于我国5省的8个库蚊复组（Culex pipiens complex）野生群体的遗传多样性进行研究,分析了4个酶系统7个基因座(ME、MDH-1、MDH-2、MDH-3、GPD、EST-2、EST-3)的酶谱资料。结果显示：（1）群体内存在不同程度的遗传变异（He为0.098～0.41）;（2）较低的基因流水平（Nm=0.64）使遗传漂变起主要作用,造成群体之间的遗传分化（Gst=0.303）,而总群体的遗传多样性相对富集于群体之内(Hs/Dst=2)。（3）库蚊群体的遗传结构属于距离隔离模式。（4）群体间的遗传一致性(或遗传距离)反映出群体间的遗传分化程度,也表明与地理位置存在对应关系。Abstract: Eight field populations of Culex pipiens complex collected from five provinces (Guangdong, Henan, Shandong, Beijing and Yunnan) in 2001 were used to study genetic diversity by starch gel electrophoresis. Data from seven loci (ME、MDH-1、MDH-2、MDH-3、GPD、EST-2、EST-3) of four isozymes were analyzed by software Biosys2.0 and FSTAT(Version 2.9.3). The results were as follows: (1) The values of He (from 0.098 to 0.41) indicated genetic variabilities of different degree in populations.(2)The low level of gene flow (Nm=0.64) could not prevent genetic drift to cause the gene differentiation between populations. The genetic diversity between populations attributed to the genetic diversity of total populations is small (Gst =0.303), and the great part is accumulated within populations (Hs/Dst=2). (3) The genetic structure of Culex pipiens complex population was the isolation-by-distance model. (4) The genetic identity (or genetic distance) revealed the scale of genetic differentiation between populations which related to the collection sites.     

Genetic Variation and Clonal Diversity of the Two Divergent Types of Clonal Populations of Leymus chinensis Tzvel on the Song Liao Steppe in the West of Northeastern China

The genetic variation and clonal diversity of two divergent types (grey-green and yellow-green) of clonal populations ofLeymus chinensis Tzvel at 14 loci were compared. Total gene diversity (HT) and the coefficient of genetic differentiation (GsT) were all higher for the yellow-green type (HT = 0.270; GsT = 0.186)than for the grey-green type (HT = 0.250; GsT = 0.157) of L. chinensis. Rare alleles usually occurred as heterozygotes rather than homozygotes and significant deviations from Hardy-Weinberg equilibrium were found only at a few loci. This indicated that these two types of populations were mainly out-crossing. Clonal diversity, evenness of clones, and mean clone size were not significantly different between the two types.We found that differences between the clone size and genetic variation of the yellow-green type of popula tions occurred with different climate and habitat population groups. However, for the grey-green type of populations, these genetic variations decreased under conditions of different climate and habitat popula tion groups.     

Chloroplast phylogeography of Dipentodon (Dipentodontaceae) in southwest China and northern Vietnam

The evolutionary history of plants in the southeast Tibetan Plateau might be the most complicated around the world because of the area's extremely complex topography and climate induced by strong tectonic activity in recent history. In this research, we implemented a phylogeographical study using chloroplast sequences (psbA-trnH and trnQ-rps16 intergenic spacer) on Dipentodon, a monotypic or ditypic genus (D. sinicus and D. longipedicellatus) distributed in southwest China and adjacent areas including Myanmar (Burma), northeast India and northern Vietnam. A total of 257 samples from 16 populations from the southeast Tibetan Plateau (D. longipedicellatus) and the Yungui Plateau (D. sinicus) were collected. The results revealed that Dipentodon had 11 haplotypes for the two intergenic spacers, high genetic diversity (h(T) = 0.902) and high genetic differentiation (N(ST) = 0.987 and G(ST) = 0.948). amova analysis showed that the component of among-population within region/species (55.25%) was unexpectedly larger than the among-species/region component (43.69%), which indicates that there is no justification for recognizing two species in Dipentodon. Correlation of pairwise genetic and geographical distances showed that Dipentodon populations in the southeast Tibetan Plateau may have suffered more habitat fragmentation than populations in the Yungui Plateau because of the uplift of the Tibetan Plateau than populations in the Yungui Plateau have. Nested clade analysis showed that 11 haplotypes formed two 3-level, three 2-level and seven 1-level clades, with eight clades showing significant geographical association. However, clade 2-1 and 2-2 did not cluster together, although they are distributed in the same region (Yungui Plateau) and belong to the same species (D. sinicus). This led not only to incongruence between haplotype network and geographical distribution of 2-level clades, but also to paraphyly of D. sinicus to D. longipedicellatus. We concluded that the incongruence and paraphyly may result from incomplete lineage sorting during the rapid and extreme tectonic events of the Tibetan Plateau. The results reported here will no doubt provide new insights into the evolution of biodiversity on the Tibetan Plateau and adjacent areas, and a historical framework for the conservation of biodiversity in this area, including Dipentodon.