细基江蓠繁枝变种（Gracilaria tenuistipitata var.Liui）群体遗传多样性的ISSR分析

运用ISSR标记对来自深圳、北海和防城港的三个细基江蓠繁枝变种群体进行遗传多样性检测,筛选出的16条ISSR引物共扩增出111条带,引物平均多态位点比例为54.95%。三个群体的多态位点比例深圳群体最高为23.42%,北海群体最低为4.50%;群体平均多态位点比例为11.12%,平均基因多样性（Hs）为0.051 3,表明细基江蓠繁枝变种群体遗传多样性较低。群体遗传分化指数为0.756 5,说明遗传变异主要存在于群体间且群体间的遗传分化水平较高。Mantel检验发现遗传距离与地理距离无关。适应生态环境选择无性繁殖模式可能是细基江蓠繁枝变种群体遗传多样性较低、群体间遗传分化大的重要因素。     

野生斑鳠西江地理群的遗传多样性分析

为了解斑鳠(Mystus guttatus)不同地理种群之间的遗传分化程度,基于RAPD技术,分析了珠江水系西江段野生斑鳠的遗传多样性。利用20个随机引物对30个斑鳠个体的基因组DNA进行了PCR扩增,共扩增出3210条DNA片段,平均每个个体扩增出107条带。在检测到的107个位点中,多态位点数为48个,占44.9%,仅有一个引物S30没有扩增出多态带。个体间最大的遗传距离0.2804,最小的遗传距离0.0467,平均遗传距离0.1526±0.037,种群内个体间平均的相似率为84.7±3.7%。     

利用微卫星DNA分子标记分析中华绒螯蟹养殖群体遗传分化

养殖河蟹苗种来自各繁育场,经过繁育场多年封闭或半封闭繁育后河蟹多样性是否降低?本研究以长江水系天然群体为对照,利用微卫星分子标记分析中华绒螯蟹(Eriocheir sinensis)江苏兴化、安徽宣城、辽宁盘锦养殖群体遗传分化。结果表明,4个群体平均有效等位基因数(Ne)分别为9.03、8.77和6.94、8.71;平均观测杂合度(Ho)为0.70～0.75;平均期望杂合度(He)为0.87～0.90;微卫星位点平均多态信息含量(PIC)介于0.84～0.87之间,呈现高度多态性;长江水系天然群体遗传多样性水平高于养殖群体。遗传分化系数F-统计量(FST)介于0.0123～0.0207(FST<0.05);分子方差分析(AMOVA)显示,大部分遗传变异(为98.64%)存在于个体间,少部分变异(为1.36%)存在于群体间。群体间FST和AMOVA分析说明,4个群体处于低等遗传分化水平,除安徽宣城群体与辽宁盘锦养殖群体间遗传分化不显著(P>0.05),其他群体间遗传分化极显著(P<0.01)。基于DA遗传距离构建NJ聚类发现安徽宣城养殖群体与辽宁盘锦养殖群体聚为一支,江苏兴化养殖群体与长江水系天然群体聚为另一支。结构分析107份参试中华绒螯蟹样本被分为二个种群,江苏兴化养殖群体与长江水系天然群体属同一种群,安徽宣城养殖群体与辽宁盘锦养殖群体为另一种群。研究显示,中华绒螯蟹养殖群体具有较高的遗传多样性水平,遗传分化水平低,具有新品种选育的利用价值。     

白孔雀微卫星DNA遗传多样性及其分类地位

利用14对蓝孔雀(Pavo cristatus)和绿孔雀(P.muticus)的微卫星标记对白孔雀基因组DNA进行扩增,发现都能扩增出特异性条带,每对引物扩增的平均等位基因数为1.71,有7对引物具有较丰富的多态性,其中MCW0080和MCW0098标记期望杂合度分别为0.7207和0.7571,多态信息含量分别为0.658和0.695,表现出丰富的遗传多样性和较高的选择潜力。白孔雀×蓝孔雀和绿孔雀群体的遗传多样性分析结果表明,白孔雀、绿孔雀和蓝孔雀3个群体的杂合度和遗传多样性水平都很低,期望杂合度分别为0.2579、0.2482和0.2744,群体间的遗传分化系数为9.7%,群体间分化极显著(P<0.001),白孔雀与蓝孔雀的亲缘关系最近,Reynolds'遗传距离和基因流分别为0.0295和8.6112,表明白孔雀不是蓝孔雀一个亚种。     

泰国产方斑东风螺养殖群体遗传多样性的RAPD分析

用随机扩增多态性DNA(RAPD)技术对泰国产方斑东风螺养殖群体的遗传多样性进行检测,从100个随机引物中筛选出21个引物对方斑东风螺的DNA进行扩增,结果表明:21个引物共检测到222条清晰且重复性好的条带,每个引物可扩增出4~16条带,分子量在200~2200bp之间,其中多态位点为156个,占70.27%;群体的Shannon多样性指数为0.2818,Nei基因多样性指数为0.2491;个体间最大遗传距离为0.291,最小遗传距离为0.066。通过与其他贝类遗传多样性的研究结果比较,可初步判断泰国产方斑东风螺养殖群体的遗传多样性比较丰富。     

窄冠型杨树杂交子代SRAP鉴定及其遗传变异研究

为鉴定杨树杂交子代真实性及阐明子代群体的遗传关系,本研究以窄冠型杨树的7个杂交子代群体和亲本为试验材料,并采用SRAP分子标记技术对其进行子代真实性鉴定及遗传变异研究。从110对引物中筛选出了8对多态性高,主条带清晰且稳定的引物,对7个杂交子代群体扩增,共产生126条谱带,其中多态性带为118条,多态带比例(PPB)达93.65%;基于Pop Gen 32软件对7个杂交组合的遗传多样性分析表明,派内杂交时,黑杨派内杂交子代的遗传多样性水平低于白杨派内的遗传多样性水平;派间杂交时,白杨做母本的子代遗传多样性比黑杨做母本的遗传多样性丰富。对其中4个杂交组合的当年杂种苗的生长量、形质指标与其亲本间遗传距离进行相关性分析,结果表明,亲本间遗传距离与苗木的地径、苗高成正相关,与其分枝角度成负相关。70个杂交子代均具有父本特征带,且经鉴定全部为真杂种,本试验结果为杨树杂交亲本的筛选及杂交子代早期鉴定提供了一定的理论依据和技术参考。     

紫茎泽兰群体遗传多样性及遗传结构的AFLP分析

紫茎泽兰是我国最为严重的入侵物种之一。本研究以中国境内的紫茎泽兰为材料，用AFLP方法研究了其群体遗传多样性及遗传分化。用筛选出的3对荧光引物，对5个地区62个群体进行AFLP分析，共扩增出490条带，其中多态性带328条，群体的遗传多样性较高(P = 66.9%，H = 0.171，I = 0.268)，主要存在于群体内，群体间的遗传分化系数Fst为0.287。AMOVA分析表明，在地区水平紫茎泽兰的遗传分化主要存地区内，群体内遗传分化占 70.25%，群体间遗传分化占21.71%，地区间的遗传分化仅占8.04%。UPGMA聚类分析结果表明，62个地理群体主要分为四大类群，并且有明显的地缘关系。Sigmaplot分析表明海拔是影响紫茎泽兰遗传多样性主要地理因子。Mantel检验表明遗传距离与地理距离成正相关(r = 0.34)，但也有例外。由此推断风媒传播可能是紫茎泽兰的主要传播方式，水媒传播可能是紫茎泽兰的另一主要传播途径；随着紫茎泽向东、向北扩散，新入侵地区的遗传多样性逐步降低。     

鳜原种群体和养殖群体遗传多样性的微卫星分析

本研究利用20对微卫星引物对鳜（Sinipelrca chuatsi）原种群体和养殖群体进行遗传多样性分析。结果表明,在鳜原种群体中检测到多态性位点14个,养殖群体11个。在两个群体中共检测到等位基因数96个,其中原种群体检测到等位基因数53个,每个位点的等位基因数在1～7之间,平均有效等位基因数为2．7390;养殖群体检测到等位基因数43个,每个位点的等位基因数在1-6之间,平均有效等位基因数为2．1284。原种群体的平均观察杂合度0．5708,Nei氏期望杂合度0．5295,平均多态信息含量PIC0．5353;养殖群体的平均观察杂合度0．3839,Nei氏期望杂合度0．4011,平均多态信息含量PIC0．5043。因此,与养殖群体相比,鳜原种群体仍有丰富的遗传多样性。本研究可为鳜种质资源的保护、监测和遗传育种提供分子水平上的数据。     

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。     

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。     

Genetic Structure of Wild and Domesticated Populations of Capsicum annuum (Solanaceae) from Northwestern Mexico Analyzed by RAPDs

Levels of genetic variation and genetic structure of 15 wild populations and three domesticated populations of Capsicum annuum were studied by RAPD markers. A total of 166 bands (all of them polymorphic) and 126 bands (125 of them polymorphic) were amplified in wild and domesticated populations, respectively. Mean percentage of polymorphism was 34.2% in wild populations and 34.7% in domesticated populations. Mean and total genetic diversity were 0.069 and 0.165 for wild populations and 0.081 and 0.131 for domesticated populations. Parameters of genetic diversity estimated from 54 bands with frequencies ≥1 − (3/n) (n = sample size) showed that 56.7% of the total variation was within and 43.3% among wild populations, whereas 67.8% of the variation was within and 32.2% among domesticated populations. AMOVA indicated that total genetic diversity was equally distributed within (48.9 and 50.0%) and among (50.0 and 51.1%) populations in both wild and domesticated samples. Wild and domesticated populations were clearly resolved in a UPGMA dendrogram constructed from Jaccard’s distances (average GD = 0.197), as well as by AMOVA (17.2% of variance among populations types, p = 0.001) and by multidimensional scaling analysis. Such differentiation can be associated with domestication as well as different origin of gene pools of the wild (Northwestern Mexico) and cultivated (more probably Central Mexico) samples analyzed. The considerable genetic distances among cultivars (average GD = 0.254) as well as the high number of diagnostic bands per cultivar (33 out of 126 bands), suggest that genetic changes associated with domestication could have resulted from artificial selection intervening in different directions, but the inclusion of more domesticated samples might clarify the nature of distinctions detected here.     

Genetic diversity analysis of hulless barley from Shangri-la region revealed by SSR and AFLP markers

For adding the hulless barley resources of Shangri-la region to the global barley resource library, a basic work was done by us to assess their genetic diversity of this region. The genetic diversity of 60 hulless barley samples collected from three counties in Shangri-la region of Yunnan Province, were studied using SSR (simple sequence repeats) and AFLP (amplified fragment length polymorphism) markers. A total of 70 alleles were detected for 19 pairs of SSR primers, and 525 band containing 464 polymorphic bands were revealed for 5 pairs of AFLP primers. The value of polymorphism information content (PIC) ranged from 0.03 to 0.86 for SSR primers. The total numbers of alleles were 51, 55, 43 in three populations and the polymorphic bands were 188, 205 and 141. The genetic distances and genetic identity among the three populations showed their close relationship. The gene diversity among populations relative to the total population diversity (Gst) was 0.13 for SSR markers and 0.02 for AFLP markers and indicated that just 13 and 2% variations were among populations, respectively. The UPGMA cluster analysis revealed that all of the samples grouped randomly rather than clustered into distinct groups corresponding to their populations, row types and spring/fall types. We concluded that there was high genetic diversity in the population of Shangri-la region and the formation of diversity was related to complex environment and inhabitants’ traditional practices.     

三个野生种群马氏珠母贝遗传多样性的RAPD分析

摘要：为了解野生种群马氏珠母贝（Pimctada martensii (Dunker.)）的遗传结构背景和开展遗传改良育种,运用RAPD技术分析了海南三亚（SW）、广东大亚湾（DW）和广西北海（BW）3个野生种群的遗传多样性。采用了18个10碱基的随机引物对3个野生种群进行分析,其中6个引物能扩增出清晰的多态带谱,扩增的DNA片段大小在含0.2~3.0 kb之间。SW、DW和BW 3个种群内的遗传相似性指数分别为0.642、0.672和0.688,Shannon多样性值分别为0.266、0.211和0.174。马氏珠母贝3个野生种群的遗传相似性依次为SW< DW < BW,而遗传多样性依次是SW > DW> BW。DW和SW相对遗传距离为0.104;DW和BW相对遗传距离为0.094;SW和BW相对遗传距离为0.212。讨论了马氏珠母贝野生种群遗传多样性差异的可能原因、种群间杂交子代的杂交优势预测及人工养殖对野生种群遗传结构的可能影响。     

Exploration of intra- and inter-population genetic diversity in <Emphasis Type="Italic">Hedysarum coronarium</Emphasis> L. by AFLP markers

Amplified fragment length polymorphism (AFLP) markers were used to characterize the genetic diversity within and among natural populations and cultivars of Hedysarum coronarium. Twelve populations within Tunisia were evaluated with three AFLP primer combinations. A total of 207 reproducible bands was detected of which 178 (86%) were polymorphic. The great discriminative power of AFLP markers and their ability to represent genetic relationships among Hedysarum plants was demonstrated. Genetic diversity within and among populations was assessed through Principal Component Analysis (PCA) and cluster analysis by using the Neighbor-joining clustering algorithm. AFLP technology has provided evidence of a high degree of intra- and inter-population genetic diversity in H. coronarium. AFLP banding patterns provided molecular markers correlated with the plants’ geotropism. In addition, AFLP markers can differentiate wild accessions from cultivars. Moreover, geographical origins did not correspond to population clustering.     

ISSR analysis shows low genetic diversity versus high genetic differentiation for giant bamboo, Dendrocalamus giganteus (Poaceae: Bambusoideae), in China populations

Dendrocalamus giganteus Munro is a high-value woody bamboo widely grown in Southeast Asia and China’s Yunnan Province. We investigated its genetic diversity in Yunnan as a prelude to considering effective breeding programs and the protection of germplasm resources. Inter-simple sequence repeat (ISSR) markers were used to assess the genetic structure and differentiation of seven populations. Seven ISSR primers generated 140 bands, of which 124 were polymorphic (88.57%). Genetic diversity within populations was relatively low, averaging 11.33% polymorphic bands (PPB), while diversity was considerably higher among populations, with PPB = 88.57%. Greater genetic differentiation was detected among populations (G _ST = 0.8474). We grouped these seven populations into two clusters within an UPGMA dendrogram—one comprised the Xinping and Shiping populations from central Yunnan, the other included the remaining five populations. Mantel tests indicated no significant correlation between genetic and geographic distances among populations. Breeding system characteristics, genetic drift, and limited gene flow (N _m = 0.0901) might be important factors for explaining this differentiation. Based on the overall high genetic diversity and differentiation among D. giganteus populations in Yunnan, we suggest the implementation of in situ conservation measures for all populations and sufficient sampling for ex situ conservation collections.     

Assessment of genetic diversity and relationships among <Emphasis Type="Italic">Triticum urartu</Emphasis> and <Emphasis Type="Italic">Triticum boeoticum</Emphasis> populations from Iran using IRAP and REMAP markers

Einkorn wheat is known as the donor of ‘A’ genome to cultivated wheat and source of many important genes. Therefore, genetic erosion in cultivated wheat provides a good reason to investigate genetic diversity in these species. In the present study, genetic diversity of 14 populations of Triticum urartu and Triticum boeoticum collected from west and north-west of Iran was examined by IRAP and REMAP markers. In total, 26 out of 36 IRAP and 41 out of 88 REMAP combinations amplified polymorphic and scorable banding patterns. IRAP and REMAP combinations produced 6.53 and 5.21 polymorphic bands per assay, respectively. Mean of polymorphism information content for IRAPs and REMAPs were 0.38 and 0.40 and marker index values for them were 2.60 and 2.09, respectively. Analysis of molecular variance based on IRAP and REMAP data revealed significant within and among population variances, although within population variance was higher than that of among population. Primer combinations based on Sukkula and Nikita retrotransposons produced the highest number of markers in the whole population. Cluster and principal coordinate analyses using REMAP data grouped the populations based on the species and geographical origin, but grouping based on IRAP could not separate the two species. However, based on both marker systems considerable diversity was observed among and within the studied populations.     

Genetic diversity of a newly established population of golden eagles on the Channel Islands,California

Gene flow can have profound effects on the genetic diversity of a founding population depending on the number and relationship among colonizers and the duration of the colonization event. Here we used data from nuclear microsatellite and mitochondrial DNA control region loci to assess genetic diversity in golden eagles of the recently colonized Channel Islands, California. Genetic diversity in the Channel Island population was low, similar to signatures observed for other recent colonizing island populations. Differences in levels of genetic diversity and structure observed between mainland California and the islands suggests that few individuals were involved in the initial founding event, and may have comprised a family group. The spatial genetic structure observed between Channel Island and mainland California golden eagle populations across marker types, and genetic signature of population decline observed for the Channel Island population, suggest a single or relatively quick colonization event. Polarity in gene flow estimates based on mtDNA confirm an initial colonization of the Channel Islands by mainland golden eagles, but estimates from microsatellite data suggest that golden eagles on the islands were dispersing more recently to the mainland, possibly after reaching the carrying capacity of the island system. These results illustrate the strength of founding events on the genetic diversity of a population, and confirm that changes to genetic diversity can occur within just a few generations.