武夷山地伯乐树种群遗传多样性的ISSR分析

伯乐树（Bretschneidera sinensis Hemsl.）为我国特有单型科珍稀濒危植物,具重要的科研价值。本研究采用ISSR分子标记对武夷山脉分布的5个伯乐树天然种群和1个移栽种群进行遗传多样性分析。结果表明伯乐树物种水平遗传多样性较高（PPB：75.70%;H_ES：0.304 5;H：0.450 1）,种群水平则较低（PPB：60.13%;H_EP：0.238 1;H：0.347 5）,MJY种群和BSZ种群分别是所有种群中遗传多样性最高和最低的。5个地理种群间遗传分化程度较高（G_st=0.218 1）,原因可能源于伯乐树的繁殖方式及生境片段化,Mantel检验也证实了地理距离与遗传距离具有显著相关性（r=0.626 7,P＜0.05）。针对伯乐树种群遗传多样性现状,建议加强现有自然种群的就地保护,促进种群自然更新。     

不同干扰生境下河口莲座蕨遗传多样性分析

该研究利用 ISSR 分子标记,对不同生境下的6个河口莲座蕨种群进行遗传多样性分析。结果表明：从44条ISSR引物中筛选出8条能够扩增出清晰、稳定条带的引物,对6个河口莲座蕨种群进行基因组 DNA扩增,共扩增出144条带,其中多态性条带119个,多态性条带比率为93.7％,Nei’s遗传多样性指数(H)为0.296,Shannon多样性指数(I)为0.457,遗传分化指数(Gst)为0.1520,种群遗传一致度和遗传距离分别为0.9138~0.9548和0.0584~0.0901;UPGMA聚类分析表明,种群间遗传距离与空间距离和生境类型有关。河口莲座蕨在不同干扰程度的生境中,种群具有高水平的遗传多样性,一定强度或频率的干扰生境中,种群遗传多样性较高,与海拔、坡度和坡向无相关性。     

北京东灵山地区不同海拔柴胡居群的遗传多样性

利用ISSR技术对北京东灵山地区不同海拔的6个柴胡居群进行分析,观察不同海拔柴胡居群的遗传多样性。结果表明,东灵山地区不同海拔柴胡居群的遗传多样性差异较大,海拔1135m居群表现出较高的遗传变异水平,高海拔居群遗传多样性较低;遗传距离与海拔差距有一定的相关性,相邻海拔的不同柴胡居群间具有相对较低的遗传距离;柴胡具有较强的遗传分化趋势,且大部分变异存在于居群内。不同海拔导致的异质生境及基因流是影响柴胡居群遗传多样性的主要原因。     

赤松毛虫地理种群的遗传变异与生态因子的相关性

采用ISSR技术分析了泰安徂徕山、青岛胶南、朝阳凌源和葫芦岛绥中4个赤松毛虫地理种群的分子遗传变异.结果表明:葫芦岛地区赤松毛虫遗传多样性相对较高,种群间有了一定程度的遗传分化;相关性分析表明,种群的遗传多样性与海拔呈显著的负相关,与年均温度、年均湿度呈一定的正相关,而与所处纬度相关关系不显著;各种群两两之间的遗传距离与海拔梯度呈正相关趋势.     

新疆枣球蜡蚧地理种群的遗传变异与生态因子的相关性

采用ISSR技术对来自新疆哈密、巴州、阿克苏、喀什、和田5个地区共计15个枣球蜡蚧地理种群的遗传变异进行了分析。结果表明:枣球蜡蚧种群中,采自阿克苏沙雅种群的遗传多样性最高,而采自巴州和静种群遗传多样性最低,各种群间的遗传背景存在明显分化;相关性分析表明,种群的遗传多样性与年均温度、年均湿度呈正相关,与寄主树龄和纬度无相关性,而与海拔呈负相关;各种群两两之间的遗传距离与年均温度差呈正相关。蚧虫在寄主树木的南向和中部发生程度最重。     

濒危植物观光木遗传多样性及遗传结构分析

采用筛选的8条ISSR引物对濒危植物观光木13个野生种群的遗传多样性及遗传结构进行分析,结果显示:物种和种群水平上多态性位点百分率分别为79.67%和46.84%,Shannon表型多样性指数分别为0.3880和0.2192,与木兰科其他近缘植物相比,遗传多样性水平较高;分子方差分析表明,观光木野生种群间遗传分化系数为0.3752,种群间存在显著的遗传距离;STRUCTURE分析和UPGMA聚类表明,参试的13个野生种群可分为3大类群;相关性分析表明,种群间遗传距离与其地理距离呈显著正相关。南昆山、笔架山、弄相山种群的遗传多样性最丰富,建议优先加以保护。     

大连地区岛屿与大陆玉竹种群遗传多样性的ISSR分析

选取大连地区大陆与海岛共有植物玉竹为研究对象,采用ISSR分子标记技术对来自5个海岛和4个大陆种群的262个玉竹个体进行遗传多样性的比较和分析。从10个筛选出的ISSR引物扩增得到120个位点信息,其中多态性条带百分率为91.67%,Nei's基因多样性指数（h）为0.346 0,Shannon信息指数（I）为0.510 8。其遗传分化系数（G_st）为0.117 4,基因流（N_m）为3.758 5。研究结果表明玉竹天然种群的遗传多样性较为丰富,种群间基因交流较为频繁,遗传距离与地理距离具有一定的相关性。通过海岛与大陆种群遗传多样性的比对发现,海岛种群的遗传多样性略高于大陆种群,表明在孤立的生境和更为复杂的选择压力下,海岛玉竹种群可能会积累更多的遗传变异从而形成较高的遗传多样性水平。本文研究结果将为进一步探讨隔离生境中天然植物种群遗传进化规律提供证据。     

承德光秃山不同海拔油松居群遗传多样性

为了解光秃山不同海拔下天然油松居群之间的遗传差异及探求遗传多样性与土壤因子的关联,为油松种源筛选和管理提供参考,本研究运用ISSR技术,对位于河北承德辽河源光秃山4个不同海拔油松天然居群共118个植株个体的遗传多样性进行分析。13个引物共扩增出177条清晰的条带,种群多态位点百分比(PPL)为60.2775%,Nei’s基因多样性指数(h)为0.2171,Shannon信息指数(I)为0.3222;不同种群遗传变异水平随海拔差异呈规律性变化,表现为沿海拔升高而呈低-高-低的分布规律,其中1354～1274 m范围的遗传多样性水平最高;在物种水平上油松具有较高的遗传多样性(PPL=98.33%,h=0.38142,I=0.5550),种群间的遗传分化系数Gst=0.6562。利用AMOVA软件对遗传变异的等级剖分结果表明,种群间有显著的遗传分化,约2/5的遗传变异存在种群间,种群内占3/5。Pearson相关分析表明,油松居群内遗传多样性与海拔、土壤养分(有机质、速效磷、速效钾含量)之间存在显著或一定的相关关系。Mantel检验结果显示,油松居群遗传距离与海拔差距、土壤养分因子的分异存在一定相关性。以上结果表明不同海拔区域的生态因子、低基因流等对油松居群间的遗传分化影响较大。     

用ISSR标记分析不同地区紫茎泽兰种群的遗传变异

利用ISSR标记技术分析了我国32个紫茎泽兰地理种群的遗传多样性,结果表明入侵我国的紫茎泽兰具有较大的遗传多样性,物种水平上的Nei's基因多样性为0．235,shannon's指数为0．372。种群间的遗传分化研究表明,大部分变异存在于种群内,总体遗传多样性中仅34．5%来源于种群之间。紫茎泽兰种群间的遗传距离矩阵和空间距离矩阵之间呈轻度正相关(r=0．542,P＜0．001),说明地理隔离可能是阻碍紫茎泽兰种群间基因交流的原因之一。不同海拔高度紫茎泽兰种群的遗传多样性水平呈现随海拔升高而降低的趋势(r=0．368,P＜0．001),各海拔区域种群的平均ISSR标记Nei's基因多样性和Shannon's指数均随海拔升高而有所降低。     

濒危植物翅果油树种群的遗传多样性和遗传分化研究

利用微卫星（SSR）标记对来自山西和陕西两省的7个翅果油树（Elaeagnus mollisDiels）种群进行遗传多样性和遗传结构研究。10对SSR标记共检测到126个位点,其中多态位点114个。在物种水平上,平均多态位点百分率为90.79%,有效等位基因数（Ne）、Nei基因多样性指数（H）和Shannon多样性指数（I）分别为1.6072、0.3166、0.4603;在种群水平上,多态位点百分率为61.99%,有效等位基因数（Ne）、Nei’s基因多样性指数（H）、Shannon多样性指数（I）分别为1.5445、0.2683、0.3815。遗传分化系数GST为0.2074,表明了翅果油树种群的遗传变异主要存在于种群内。基因流Nm为1.9111〉1,说明种群间基因交流可以阻止由于遗传漂变导致的遗传分化。聚类结果表明,翅果油树种群间的遗传距离与地理距离有一定的相关性,经Mantel检验,种群的地理距离与遗传距离之间呈正相关,但未达到显著水平（p〉0.05）。结果表明,遗传多样性水平与物种本身特性和不同干扰生境有关,濒危植物并不一定表现为遗传变异水平的降低。     

Genetic diversity pattern of Stipa purpurea populations in the hinterland of Qinghai–Tibet Plateau

Stipa purpurea is among constructive endemic species in alpine meadow and steppe on the Qinghai–Tibet Plateau. To reveal the genetic diversity of this species and its relationship with geographic distribution pattern, we sampled eight populations across a northward transect with an increasing aridity gradient in the hinterland of Qinghai–Tibet Plateau. Their genetic diversity was quantified using eight intersimple sequence repeat (ISSR) primers. We found that S. purpurea had relatively low genetic diversity ( H _e = 0.135) but significant genetic differentiation among populations ( G _st = 0.391), indicating relatively more genetic diversity retained within populations. A Mantel test revealed a significant relationship between genetic and geographic distance in the S. purpurea populations. The genetic diversity tended to decrease with increasing latitude and longitude, while no significant relationship was found between genetic diversity and altitude, suggesting the possible influences of humidity and temperature on genetic diversity of alpine plant. We propose conservation measures for this plant on the plateau.     

承德大窝铺不同海拔与群落类型天然油松种群遗传多样性

利用ISSR技术分析了河北承德大窝铺3个不同海拔、4个不同群落类型的油松天然种群的遗传多样性与遗传分化,探讨了天然油松种群遗传多样性与主要生态因子的关系.结果表明:天然油松种群具有较高的遗传多样性,13个筛选出的随机引物共检测出180个位点,总多态位点比率分别达到73.33％和91.11％.海拔影响油松种群的遗传多样性,中海拔( 1070～1130 m)高于高海拔(1230 ～1350 m)和低海拔(910 ～970 m)(多态位点比率分别为63.33％、51.67％和59.44％);群落类型与种群的基因组结构变异之间存在一定的内在联系.遗传变异多来自种群内部(分别为90.45％和75.22％),种群分化不明显;群落类型对天然油松种群间遗传变异和基因交流(Gst为0.248,Nm为1.517)的影响高于海拔对其影响(Gst为0.095,Nm为4.738).可以认为,群落类型对大窝铺天然油松种群遗传分化有较大影响.     

Genetic variation and clonal diversity of Bromus ircutensis Kom. in the Otingdag sandy land detected by ISSR markers

Genetic variation and clonal diversity of nine populations of Bromus ircutensis Kom. from the Otingdag sandy land were investigated using Inter Simple Sequence Repeat (ISSR) markers. A total of 102 bands were amplified by using II ISSR primers chosen for the study. Among those 99% were polymorphic indicating high level of genetic variation at the species level with a mean genetic diversity (H) of 0.292 and Shannon information index (1) of 0.450. Percentage of polymorphic loci (PPL) of nine populations was 76.48% on average, which provides more evidence of considerable genetic variation at the population level. AMOVA analysis revealed that total genetic variation was higher within populations (87.06%) than between populations (12.94%), which is mainly the result of the extensive gene flow (Nm = 1.682) among B. ircutensis populations. UPGMA cluster analysis divided the nine populations into two groups. There was significant or moderate negative correlations between genetic diversity parameters (PPL, H, 1) and longitude or latitude. Mantel test also showed a significant correlation between geographical distance and genetic distance (r = 0.681, p = 0.002). Our findings indicated that distribution of B. ircutensis populations was influenced by geographical and ecological factors. Clonal diversity was also high with 108 individuals identified by 11 ISSR primers being all of different genets. Our results provide a molecular basis for sustainable management and conservation ofB. ircutensis in the study area.     

Genetic diversity analysis of Rhododendron aureum Georgi (Ericaceae) located on Changbai Mountain using ISSR and RAPD markers

Rhododendron aureum Georgi (Ericaceae) is a perennial alpine shrub endemic to Changbai Mountain in China. We used ISSR and RAPD markers to describe the diversity and genetic structure within and among four natural populations located at different altitudes. DNA from 66 individuals was amplified with ten ISSR markers and seven RAPD markers. High genetic diversity was observed by these two techniques at the species level. The genetic diversity of populations increased with altitudinal gradients from low to high. The coefficient of gene differentiation (G_ST 0.3652 in ISSR and 0.2511 in RAPD) and AMOVA analysis revealed that most genetic diversity was distributed within populations (61.96% in ISSR and 70.23% in RAPD). The estimate of gene flow based on G_ST was 0.8690 in ISSR and 1.4910 in RAPD. The UPGMA clustering results using ISSR and RAPD showed that all individuals from the same altitude were gathered together, and the two populations (TYD2a and YHLa) from middle altitudes always clustered together. Compared with populations from different altitudes, similar genetic diversity and low genetic differentiation were obtained from populations at the same altitudes, as revealed by ISSR markers. In addition to the reproductive strategy of R. aureum, these data highlight that local environmental conditions may play an important role in shaping the diversity and genetic structure of this species.     

Genetic diversity of natural populations of Taxus mairei

Taxus mairei (Lemée & Lév.) S.Y. Hu ex T. S. Liu is a vulnerable tree species, and it is also a precious timber species in China. We used 13 microsatellites to assess the genetic diversity and differentiation of 665 T. mairei samples from 18 natural populations. A total of 291 alleles were detected. The average number of alleles (N_a?=?22.39), expected heterozygosity (H_e?=?0.74), polymorphic information content (PIC?=?0.86) and Shannon diversity index (I?=?1.66) of the loci indicated a high level of genetic diversity in natural T. mairei populations. Moreover, gene flow was more active among populations (N_m?=?1.62) than within populations. Among the 18 populations, the Xinfeng population in Jiangxi Province has the highest genetic diversity. Although each of the studied populations should be protected from further deforestation and agricultural expansion, the Xinfeng population deserves the highest conservation priority. The results based on analysis of molecular variance showed that genetic variation occurred mainly within populations (84.90%; P?<?0.001), which indicated that the degree of genetic differentiation of the natural populations of T. mairei was low. Based on UPGMA, the 18 populations were categorized into two groups. A Mantel test showed that there was no significant correlation between standard genetic distance and geographical distance or altitude differences among the populations. The genetic clustering results also indicated that there are varying degrees of gene penetration among natural populations of T. mairei. The information presented here forms the basis for the development of genetic guidelines for appropriate conservation programs.

     

日本岛屿山茶种群遗传结构的ISSR分析

为查明日本岛屿山茶种群的生存状况及了解岛屿隔离对山茶种群遗传结构的影响,采用ISSR分子标记,利用筛选的20条引物对日本5个山茶（Camellia japonica）种群的遗传结构进行分析。结果表明：山茶种群的多态位点百分比（PPB）为70.29％,Nei’s基因多样性指数（H_E）为0.281 9,Shannon信息多态性指数（H）为0.409 5,与其它岛屿种群相比遗传多样性水平较高,表明山茶种群的生存状况较好。基因分化系数G_st=0.205 7,种群间具有较高的遗传分化;地理距离与遗传距离具有显著相关性（r=0.821 7,p<0.05）,UPGMA也将同岛种群聚在一起,表明岛屿隔离对山茶种群的遗传分化具有重要影响。借鉴日本岛屿山茶种群的保护经验,建议加强我国岛屿山茶种群的就地保护力度,同时建立山茶种质资源库,促进基因交流。     

麦无网长管蚜不同地理种群遗传多样性的ISSR标记研究

为阐明麦无网长管蚜Metopolophium dirhodumus不同地理种群的遗传多样性,利用ISSR分子标记对6个地区（河北保定、定州、石家庄、邢台、邯郸,山东聊城）的麦无网长管蚜种群进行了遗传多样性研究。23条ISSR引物扩增出了297条清晰条带,其中172条（57.91%）具有多态性。遗传多样性分析结果表明：麦无网长管蚜群体间的遗传多样性（57.91%）高于群体内的遗传多样性（26.24%）,其中河北保定种群和河北邯郸种群的种群内遗传变异最小（24.92%）,河北石家庄种群的种群变异最大（41.75%）,河北和山东地区的种群（除河北石家庄）之间没有显著遗传差异。根据种群变异来源分析,有26.44%遗传变异来源于种群间,73.56%变异来自于种群内（Gst=0.2644）,不同地理种群间并没有出现分化现象（Nm=1.3910）。利用不加权算术平均法（UPGMA）对6个种群进行统计分析,构建进化树,发现6个种群分为了两大类,而其地理距离与遗传距离并不存在相关性,地理空间并未对其种群间的基因交流产生影响。麦无网长管蚜有较高的遗传多样性,而各个种群间并没有明显遗传分化的趋势。本研究有关麦无网长管蚜不同地理种群基因流和遗传变异将为控制麦蚜危害和田间综合防治提供必要的数据支持。