湖南典型茶树地理种群遗传多样性

利用RAPD分子标记技术,对湖南典型茶树安化云台山种(Camellia sinensis var.sinensis)、城步峒茶(C.sinensis var.assamica cv.Duntsa)、汝城白毛茶(C.ptilophylla)和江华苦茶(C.sinensis var.assamica cv.Jianghua)4个地理种群的240个单株的遗传多样性、种群内和种群间的遗传变异进行了研究。结果表明,21个10碱基随机引物共检测到226条谱带,其中多态性谱带为201条,占88.9%。遗传多样性分析结果显示:Shannon's多样性指数为0.43,种群内变异占74.7%,而种群间变异占25.3%;Nei's指数群体总基因多样性(HT)为0.37,群体内平均基因多样性(HS)为0.28,群体间的基因多样性(HST)为0.09,群体Nei's基因分化系数(GST)为0.23,说明76.7%的变异存在于种群间,群体内的变异占了总变异的23.3%,与Shannon's多样性指数相比基本一致,均表明种群内有较丰富的遗传变异;种群间的基因流(Nm)为0.74,显示种群间的基因交流有限。     

细鳞鱼三个野生种群的遗传多样性AFLP分析

细鳞鱼是我国一种珍贵的淡水经济鱼类,在人类和环境因素的影响下数量急剧下降。本文采用扩增片段长度多态性（Amplified Fragment Length Polymorphism, AFLP）技术对牡丹江（Mudanjiang River, MD）、鸭绿江（Yalujiang River, YL）和乌苏里江（Wusuli River, WSL）的三个细鳞鱼野生种群共72个个体进行了遗传多样性分析。结果显示,12对选择性扩增引物共扩增得到559个位点,其中多态性位点541个,多态性百分比为96.78％。文中对3个群体的Shannon多样性指数,Nei氏基因多样性等参数进行了分析。其总基因多样性Ht平均值为0.3512±0.0208;种群内基因多样性Hs平均值为0.2137±0.0152;群体间的基因多样性Dst为0.1375。基因分化系数Gst为0.3914,种群内的基因多样性占总群体的60.85%,种群间为39.15%,而基因流系数Nm 为0.7776。分子方差分析（AMOVA）表明：群体平均遗传分化系数Fst为0.55336,变异来源有44.84%来自群体间,55.16%来自群体内。三个群体中牡丹江群体的细鳞鱼种内多态性比例最高,而乌苏里江群体最低。     

我国部分地区小麦叶锈菌遗传多样性的SSR分析

小麦叶锈菌(Puccinia triticina)引起的小麦叶锈病是小麦上的重要病害。为了解小麦叶锈菌遗传多样性及其亲缘关系,本研究利用简单重复序列(simple sequence repeat,SSR)标记技术对2009年采自河北、河南、山东、四川4省的小麦叶锈菌株进行SSR分析。小麦叶锈菌的观察等位基因数(Na)为1.75,有效等位基因数(Ne)为1.40,Shannon信息指数(I)为0.35,Nei’s基因多样性指数(H)为0.23,多态性百分率为75.29%,其中河北、河南和山东的叶锈菌群体遗传多样性水平高于四川群体。聚类分析表明,在相似系数0.96处4个群体聚为2组,河南、山东及四川群体聚为一组,河北群体自成一组,其中河南和山东群体亲缘关系最近。小麦叶锈菌具有一定的遗传变异,群体间遗传变异占总变异的8.93%,群体内遗传变异占总变异的91.07%。小麦叶锈菌群体间每代迁移数Nm为6.10。小麦叶锈菌遗传多样性丰富,群体间遗传相似性较高,亲缘关系与地理分布具有一定相关性。群体内遗传变异是群体遗传变异的主要来源。本研究说明群体间存在广泛的菌源交流,为明确小麦叶锈病流行区系和叶锈菌传播路线提供了基础资料。     

我国主要棉花栽培群体的遗传多样性分析

摘 要：利用ISSR分子标记对我国44个棉花栽培品种（拟似为6个群体）进行遗传多样性分析。筛选出的11个引物在所有品种中共扩增出90条带,其中70条为多态性条带,多态性条带百分率(PPB)达76.1%,Popgene32软件分析结果表明,新疆种群的遗传多样性水平最高(PPL=91.43%,H=0.3769,I=0.5464),其次是中棉种群、河南种群,而河北、山东、山西3个种群的遗传多样性水平相差较小,6个棉花种群在其总的遗传变异中有82.42%的存在于群体内,群体间的遗传变异仅占总变异的17.58%,群体分化系数Gst=0.1759,群体间总的基因流的估算值Nm=2.34。由聚类分析可知,山西、山东、河北种群的亲缘关系最近,先聚合在一起,然后依次与河南、中棉所种群聚类,最后与亲缘关系最远的新疆种群聚合。     

中国主要棉花栽培群体的遗传多样性分析

利用ISSR分子标记对我国棉花栽培品种中的38个陆地棉(Gossypium hirsutum)和6个海岛棉(Gossypium bar-badense)共44个品种(按来源划分为6个品种群,6个海岛棉品种均属于新疆品种群体)进行遗传多样性分析表明,筛选出的11个引物在所有品种中共扩增出90条带,其中70条为多态性条带,多态性条带百分率(PPB)达77.78%,Popgene32软件分析结果表明,新疆品种群的遗传多样性水平最高[PPB=91.43%,H(基因多样性指数)=0.3769,I(信息指数)=0.5464],其次是中棉所品种群,河南品种群排位第三,而河北、山东和山西3个品种群体的遗传多样性水平相差较小,其中山西品种群遗传多样性水平最低(PPB=58.57%,H=0.2484,J=0.3587).6个地方棉花栽培群体在总的遗传变异中有82.42%存在于群体内,群体间的遗传变异仅占总变异的17.58%,群体间分化系数Gst=0.1759,群体间总的基因流的估算值.Nn=2.34.聚类分析结果表明,山西、山东和河北品种群体的亲缘关系最近,先聚合在一起,然后依次与河南和中棉所品种群体聚类,最后与亲缘关系最远的新疆品种群体聚合.     

应用RAPD分析川西北高原老芒麦自然居群的遗传多样性

利用RAPD标记对来自青藏高原东南部川西北高原的8个老芒麦自然居群的遗传多样性和群体遗传结构进行了分析和评价。从150个RAPD引物中筛选出25个能扩增出高度重复性条带的引物。这25个引物共扩增出370条可分辨的条带,其中291条(占78.65%) 具有多态性,表明供试居群在物种水平上存在较高水平的变异。同时各居群的多态性位点比率(PP)在46.49%到53.78%之间变化,表明群体水平的变异较低。居群的平均基因多样性(HE)为0.176(变幅为0.159~0.190),而物种水平的平均基因多样性达0.264。基于Nei’s基因多样性、Shannon指数和贝叶斯方法的群体分化系数分别为32.0%、33.7%和33.5%。AMOVA 分析表明居群内遗传达到总变异的59.9%,而居群间变异仅有40.1%,但二者均达到极显著水平(P < 0.001)。居群间每世代迁入个体数(Nm)达到0.503个。各居群间存在较高的Nei’s遗传一致度。本研究获得的老芒麦的遗传结构不同于已报导的大多数披碱草属物种。另外,基于聚类分析及AMOVA的结果均表明各居群间存在较为明显的地理分化,8个居群分化为采集地的南部和北部2个分支。总之,研究结果表明来自青藏高原东南部的老芒麦居群具有较高水平的遗传变异。在该地区应尽量选择遗传多样性高的老芒麦居群实施就地保护。     

利用SSR和RAPD标记分析中国部分地区晚疫病菌群体遗传多样性

利用SSR和RAPD对来自福建、黑龙江、河北和内蒙古4个地理群体的80个马铃薯晚疫病菌（phytophthora infestans）株进行了遗传多样性分析。13对SSR引物共扩增出76条谱带,多态性条带比率78.9%,相似系数变化范围0.00～0.42之间;筛选出的14条RAPD引物共扩增出189条谱带,多态性条带比率95.2%,相似系数变化范围0.04～0.66之间。遗传多样性分析表明,在4个群体中,福建群体的多样性更为丰富。遗传相似性分析显示,黑龙江和内蒙古两个群体间的遗传相似性最高,而福建和河北两个群体间的遗传相似性最低。聚类分析显示,来自南方福建的菌株与来自北方黑龙江、河北和内蒙古的菌株亲缘关系较远,且福建群体分布于更多的聚类组,显示出更高的遗传变异度。     

2个中国藏獒群体遗传多样性及遗传分化的研究

本研究以青海土种犬和藏狮犬为对照,采用RAPD技术对河曲藏獒和青海藏獒群体的遗传多样性及遗传分化进行了分析。研究结果表明,河曲藏獒和青海藏獒群体的多态性位点百分率分别为85.53%和98.16%,平均多态性位点百分率为91.85%。藏獒群体遗传变异分析显示两个藏獒群体的有效等位基因数(Ne)、Nei氏平均预期基因杂合度(H)和Shannon遗传信息指数(I)的平均值分别为1.5354、0.3191和0.4807;且两个藏獒群体93.09%的变异来自群体内,仅6.91%变异来自群体间;两个群体间的基因流为3.3679。研究还发现两个藏獒群体之间的Nei氏标准遗传距离(D)为0.0505。本研究结果说明藏獒群体内遗传变异丰富,不同地域的藏獒群体之间存在广泛的基因交流,群体之间遗传分化程度很低,这为藏獒品种资源保护与合理开发利用提供了参考。     

云纹石斑鱼和鞍带石斑鱼及其杂交后代遗传性状分析

微卫星标记是鱼类遗传多样性分析的有效方法,本研究利用石斑鱼(Epinephelus sp.)近缘种的27对微卫星引物,分析鞍带石斑鱼(E.lanceolatus)(♂)、云纹石斑鱼(E.moara)(♀)及其杂交子一代云龙斑的遗传性状,其中有25对SSR标记在云龙斑中检测到多态性。通过Popgene32软件计算有效等位基因数(effective alleles number,Ne),期望杂合度(expected heterozygosity,He),观测杂合度(observed heterozygosity,Ho),香侬信息指数(Shannon index,I),Nei氏遗传距离(genetic distances,Nei),多态信息含量(polymorphism information content,PIC),总体近交系数(overall inbreeding coefficient,Fit),群体内近交系数(inbreeding coefficient in population,Fis)及遗传分化系数(genetic differentiation coefficient,Fst)等遗传多样性参数,分析群体间的遗传变异情况。结果表明,在3种石斑鱼群体中,云纹石斑鱼平均有效等位基因数最多(2.8926),云龙斑次之(2.8010),最小的是鞍带石斑鱼(2.0564)。云纹石斑鱼、鞍带石斑鱼和云龙斑共3个群体的平均观测杂合度分别为:0.6046、0.5661和0.5010,平均多态信息含量分别为:0.579 8、0.5446和0.342 0。3个群体总近交系数为0.150 8,群体间遗传分化系数为0.067 7,表明有93.23%的遗传变异来自群体内个体间的差异,6.77%的遗传变异来自群体间,群体间近交系数为-0.072 2,群体间基因流(Nm)为2.396 3。基于Nei's遗传距离构建UPGMA聚类分析,显示云龙斑与云纹石斑鱼遗传相似度较高,遗传距离较近。本研究结果在分子水平上为杂交品种云龙斑的杂种优势性状形成及杂交种质鉴定提供了遗传基础。     

四个鲤鱼种群遗传多样性的AFLP分析

本文采用AFLP技术对黑龙江野鲤、黄河鲤、建鲤和荷包红鲤4个鲤鱼种群共96个个体进行了遗传多样性分析。结果显示,8对选择性扩增引物共扩增得到502个位点,其中多态性位点273个,多态性比率为54．38％。同时对4个种群的Shannon多样性指数,Nei’s基因多样性等参数进行了分析,结果表明,4个种群的Shannon多样性指数分别为0．2114±0．2705,0．1825±0．2694,0．1888±0．2587和0．1600±0．2426,Nei’s基因多样性指数分别为0．1398±0．1872,0．1225±0．1863,0．1235±0．1774和0．1036±0．1636;总基因多样性（H4）平均值为0．1721±0．0350;种群内基因多样性（Hs）平均值为0．1224±0．0190;基因分化系数（Gst）为0．2892,种群内的基因多样性占总群体的71．08％,种群间为28．92％,而基因流系数（Nm）为1．2291。另一方面,分子方差分析（AMOVA）结果表明,种群平均近交系数（Fst）为0-31191,变异31．19％来自种群间,68．81％来自种群内。4个种群中黑龙江野鲤的种内多态性比例最高,而荷包红鲤种群最低,并且4个鲤鱼种群当前的种质资源良好,具有一定的种群稳定性;建鲤已经开始分化,与亲本荷包红鲤亲缘关系逐渐分化,逐步形成自己稳定的遗传结构。本研究为探讨鲤鱼种群的遗传特性和遗传分化提供参考,也为其种质资源的保护及合理利用提供科学依据。     

Using SSR markers to determine the population genetic structure of wild apricot (<Emphasis Type="Italic">Prunus armeniaca</Emphasis> L.) in the Ily Valley of West China

Genetic structure of three wild populations (Xinyuan, Gongliu and Daxigou) of apricot in the Ily Valley, Xinjiang Uygur Autonomous Region of China, was investigated with microsatellite (simple sequence repeat, SSR) markers. The higher polymorphism and greater transportability of these markers between Prunus species proved SSR markers were much efficient for conducting genetic diversity studies in wild apricot. Nei's gene diversity (He) and Shannon's index of diversity (I) were 0.287 and 0.458, respectively. This indicated that the wild apricot in the Ily Valley still maintained a relatively high level of diversity. The Gst of 0.137 and Fst of 0.164 revealed that genetic variation mainly resided among individuals within populations (83.6–86.3%). Population differentiation could also be found according to the distribution of SSR alleles between the populations. Mantel test showed the genetic distance between populations was significantly correlated to the geographical distance. The modest amount of gene flow (2.684) would reduce the disjunction between wild apricots. The long-distance dispersal of pollen by insects was probably the main way of gene flow between populations. Based on the study of population genetic structure, an effective conservation strategy of the species was discussed.     

Genetic variation in the endangered Inner Mongolia endemic shrub Tetraena mongolica Maxim. (Zygophyllaceae)

Tetraena mongolica Maxim, is a critically endangered and endemic species of westem Inner Mongolia in China. Genetic variability within and among eight extant populations of this species was assessed using ISSR PCR (13 primers). We expected a low genetic diversity level, but our results revealed an intermediate level of intraspecific genetic diversity, probably resulting from this species being in a refuge during the last glaciation (at population level: P=48.1%, A_e=1.305, H_E=0.177 and H_pop=0.264; at species level: P=63.3%, A=1.368, H_T=0.213 and Hsp=0.324). A low level of genetic differentiation among populations was detected based on Nei's genetic diversity analysis (16.91%), Shannon's diversity index (18.83%) and AMOVA (15.2%). Populations shared high levels of genetic identity (I=0.9516±0.013). The extensive gene flow was a plausible reason for the low genetic differentiation.     

Microsatellite variability within and among local landrace populations of tea, Camellia sinensis (L.) O. Kuntze, in Kyoto, Japan

Genetic variability within and among eight landrace populations of tea (Camellia sinensis (L.) O. Kuntze) located in southern Kyoto, Japan, was surveyed with six microsatellite markers. The average number of alleles per locus was 3.83 to 4.67 for landrace populations, whereas the corresponding value among modern cultivars and breeding lines was 6.63. Expected heterozygosity values averaged over loci within landrace populations ranged from 0.498 to 0.723. A similar level of variation, 0.682, was observed for cultivars and breeding lines. High fixation index values (0.177–0.417) for each population are consistent with biparental inbreeding within the population. Genetic differentiation among local populations was extremely low with F _ST = 0.062, although AMOVA revealed significant differentiation among landrace populations. We propose that these populations share a common ancestral gene pool and that some degree of artificial selection within each population has been performed by local farmers. Neighbor-joining analysis revealed that genetic relationships among populations reflect geographical location of populations. This might result from more frequent genetic exchange by nearby farmers.     

Genetic diversity in wild Tunisian populations of Mentha pulegium L. (Lamiaceae)

The allozyme variation of 15 Tunisian wild populations of Mentha pulegium L. threatened by human activities (clearing, hard-grazing, ploughing, traditional uses) was surveyed by the analysis of 14 isozyme loci using horizontal gel starch electrophoresis. The species exhibited a high level of genetic variation within populations (the mean Ap = 2.20, P = 72%, Ho = 0.349 and He = 0.229), which indicates a predominately outcrossing mating system and the recruitment of new genotypes via dispersal seeds. The genetic structure analysis of the populations using F statistics indicates no inbreeding, and showed an excess of heterozygosity for few loci. The moderate differentiation of populations (F_ST = 0.110) and the low rate of gene flow between them (Nm = 2.02) might been caused by recent isolation of the populations through biotope disturbances. The value of Nei's genetic identity varied from 0.839 to 0.999 reflecting a relatively low genetic divergence between populations. Cluster analysis using UPGMA method and Nei's genetic identity values, showed that populations geographically close didn't always cluster together. However, populations within the same bioclimatic stage generally subclustered together indicating that differentiation between bioclimatic regions occurred.     

华东竹黄菌不同居群遗传分化的RAPD分析

为了解竹黄地理居群间的遗传分化,本研究采用随机引物扩增多态性DNA分子标记技术对江苏、安徽和浙江3省的8个居群共32个竹黄样本进行了遗传多样性分析。从50个RAPD引物中筛选得到了5个随机引物,对供试材料的DNA进行扩增,共检测出77个位点,其中多态性位点52个,多态性位点比率为67.53%。UPGMA聚类分析结果表明,这8个居群分为三类：安吉居群、临安居群、宜兴居群、广德居群和泾县居群聚为一类;宁国居群和休宁居群聚为一类;淳安居群单独为一类。遗传多样性分析表明8个竹黄居群中,淳安居群的遗传多样性水平最高,安吉居群的遗传多样性水平最低。Nei＇s基因多样性指数和Shannon信息指数均表明竹黄物种水平的遗传多样性高于居群水平。     

Genetic variation in the threatened South American conifer Pilgerodendron uviferum (Cupressaceae), detected using RAPD markers

Pilgerodendron uviferum (Cipres de las Guiatecas, Cupressaceae) is a long-lived conifer, endemic to southern Chile and Argentina, reaching a southern limit in Tierra del Fuego. Remnant populations are generally fragmented and highly disturbed because of exploitation for timber, grazing and fire. The extent of genetic variation within and between 16 populations of this species, distributed throughout its range, was assessed using random amplified polymorphic DNA (RAPD) markers. Eight 10-mer primers produced a total of 84 scorable markers, 30 of which (35.7%) were polymorphic. AMOVA indicated that 18.6% of the variation recorded was attributable to differences between populations, a relatively high value compared with other conifers from the region. Pair-wise Phi_st comparisons between populations were all significant at P<0.05, with one exception, highlighting a high degree of population differentiation. Values of Shannon's diversity index (S) differed significantly among populations (P=0.002, ANOVA), values ranging from 0.337 to 0.716, suggesting that some populations are currently characterised by very low genetic variability. Current patterns of genetic variation were related to biogeographic history and human impact. The high degree of population differentiation recorded here highlights the need for additional conservation measures for this species, both in terms of incorporating further populations into the protected areas, and the restoration of severely degraded populations, to ensure their continued viability.