基于叶绿体微卫星研究鄂报春谱系遗传结构

鄂报春Primula obconica作为一种广泛栽培的园艺植物,其野生居群的遗传多样性及遗传结构的研究还少见报道。本文通过叶绿体微卫星分析了17个鄂报春野生居群(共278个个体),共发现4个多态性位点(16个等位基因),得到14个单倍型。结果表明鄂报春具有很高的总基因多样性(HT=0.971)和极低的居群内基因多样性(HS=0.028);分子方差分析(AMOVA)显示98%的变异存在于居群间。这些结果说明早期的生境片断化及有限的种子传播能力是造成当前遗传结构的重要原因。Nst值显著大于Gst值,表明关系相近的单倍型会出现在相同的地区内,同时最小生成树(MST)的分析结果证实了这样的结论。我们在最小生成树的两个组中推断出一些古老单倍型,并推测在冰期时湖北和我国的西南地区可能是该物种的避难所。     

湖北星斗山台湾杉居群的遗传多样性研究

采用随机扩增多态性DNA(RAPD)方法对孑遗植物台湾杉分布于湖北星斗山的野生和栽培居群共42个个体进行了遗传多样性分析。从60个随机引物中筛选出13个引物,共扩增出155条清晰谱带,多态位点百分率为72.9%。野生居群和栽培居群的多态位点百分率分别为65.81%和59.35%;Nei’s基因多样性分别为0.2001和0.1911;Shannon’s信息指数分别为0.3120和0.2946。野生居群的遗传多样性高于栽培居群,表明这些原生古树的后代出现了一定程度的遗传衰退。用UPGMA方法对42个单株聚类可知,来自野生群体的个体和来自栽培群体的个体明显地各聚为一类。尽管孑遗物种台湾杉在湖北仅有一个野生群体,且为零星分布,总个体数40多株,但仍保持较高的遗传多样性水平,这说明遗传多样性不是导致其种群濒危的主要原因,导致台湾杉种群濒危的原因可能与台湾杉自然种群及群落所处生境的直接破坏及其本身生物学和生态学特性所导致的自然更新不良有着密切的联系。     

水杉栽培居群的遗传多样性研究

利用RAPD技术,对9个水杉(Metasequoiaglyptostroboides)栽培居群的遗传多样性进行了初步研究。用10bp的随机引物16条,共扩增出103个位点,其中37个为多态位点,占35.92%。各居群的多态位点百分率在16.50%~33.01%之间。POPGENEversion1.31软件处理结果如下:居群的Shannon’s信息指数为0.1930。遗传距离在0.0130~0.0650之间,遗传一致度在0.9370~0.9871之间。AMOVA分析结果显示遗传变异主要存在于居群内,占89.05%,居群之间有一定的分化。上述结果表明水杉栽培居群的遗传多样性略低于自然居群,涵盖了自然居群近80%的遗传多样性。由此可以确认栽培水杉的种源是经过混合的,它们在相当程度上代表了自然居群的遗传多样性水平。采自潜江的9株丛枝水杉(Metasequoiaglyptostroboidesvar.caespitosa)没有扩增出特有位点,将其视为一个居群根据遗传一致度作UPGMA聚类分析时,该居群和湖北的3个居群及南京(NJ)、成都(CD)居群聚在一起;单株聚类时丛枝水杉也没有聚成独立的一支,而是比较分散,因此不支持将丛枝水杉作为水杉的一个变种的分类处理。从亲缘关系上看,丛枝水杉应当归属于湖北潜江蚌湖种子园(BH)和湖北潜江广华(GH)居群,这与其分布现状也是吻合的。     

Wild sunflower diversity in Argentina revealed by ISSR and SSR markers: an approach for conservation and breeding programmes

Wild sunflower Helianthus annuus originates from North America and has naturalised in Argentina where it is considered invasive. The present study attempts to assess the genetic diversity using two different molecular marker systems to study the wild genetic patterns and to provide data applicable to conservation and breeding uses. Ten natural populations sampled throughout the wild range and six inbred lines were studied using inter‐simple sequence repeat (ISSR) and simple sequence repeats (SSR) markers. A total of 64 ISSR bands and 29 SSR alleles were produced from 106 wild and cultivated plants. We found 9 ISSR private bands and 21 SSR private alleles in wild accessions, but no private bands/alleles were found in cultivated sunflowers. Molecular variability in wild populations was approximately 60% higher than in inbred lines. Local wild sunflowers kept considerable diversity levels in comparison with populations in the centre of origin (approximately 70%) and therefore they might possess a potential for adaptive evolutionary change. Analysis of molecular variance (AMOVA) indicated population structure with nearly 20% of genetic variability attributable to between‐population differentiation. Principal coordinate analyses (PCO) grouped wild populations from different geographic locations, and a Mantel test showed low congruence between genetic distance (GD) and geographic distances (GGD); hence, molecular data could not rule out multiple wild introduction events. Low correlations were found between ISSR and SSR GD at individual and population levels; thus, divergent evolutionary groups were not evident in local wild sunflowers. Several genetic diversity criteria were utilised to assign conservation value and certain wild populations emerged as interesting sites for more extensive sampling.     

鄂报春(Primula obconica Hance)亲缘地理学的初步研究

为了获得鄂报春（Primula obconica Hance）的种内亲缘地理学信息,对叶绿体基因组上非编码区trnL-trnF的序列变异进行了分析.获得的20个单倍型具有一定的地理分布结构.对这些单倍型进行系统发育分析,得到了三个主要分支：东部分支广泛分布于中国东南部、湖南、湖北、四川和云南;四川分支分布于四川西部;云南分支分布于云南西北部.东部分支分布面积较后两个分支大,并且在东部分支中可以发现一定的演化关系.结合古气候学和地质学信息,推测东部分支中现存的单倍型由冰期时气候变冷导致鄂报春快速迁移而形成,云南、四川分支中的单倍型可能是在各自的避难所中得以保存.同时本文也简要地探讨了鄂报春几个亚种之间的分类学关系.     

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.     

湖北中华蚊母ISSR遗传多样性分析及保护策略

利用ISSR分子标记技术,对湖北省三峡库区内中华蚊母的4个自然居群和1个迁地居群的遗传多样性和遗传结构进行了分析.结果表明,中华蚊母具有较高水平的遗传多样性,8个引物共得到47条带,其中多态性条带为44,多态性条带百分率(PPF)为94%;每个位点的等位基因数(A)为2,有效等位基因数(Ae)为1.37;总遗传多样性Nei s基因多样性指数(Hp)为0.237 9,Shannon信息多样性指数(I)为0.386 8,高于地方特有种平均水平.5个居群总的遗传变异Ht为0.238 7,居群内的遗传变异Hs为0.212 9,居群间的遗传分化系数Gst为0.108 0,表明在总的遗传变异中有89.2%的变异存在于居群内,仅10.80%存在于居群间;居群间的基因流Nm为4.130 6,表明居群间有较大程度的基因交流.UPGMA聚类分析和主成分分析显示中华蚊母在湖北境内主要分为两个居群组,在湖北境内的长江三峡沿岸沿渡河、香溪、乐天溪及三峡植物园居群聚为一大类,离长江沿岸较远的高家堰聚为另一大类.迁地保护居群三峡植物园的遗传多样性水平略高于中华蚊母自然居群的遗传多样性,说明三峡植物园对中华蚊母遗传多样性的迁地保护策略是基本成功的.     

小菜蛾不同地理种群遗传多样性的ISSR标记研究

为阐明小菜蛾Plutella xylostella不同地理种群的遗传多样性, 应用ISSR技术对我国小菜蛾8个地理种群的遗传多样性进行了研究分析。15条引物扩增出395条ISSR条带, 其中多态性条带占89.11%, 全部个体显示了各自独特的ISSR图谱。ISSR标记的遗传多样性分析结果表明： 小菜蛾无论在物种水平上（P=89.11%, H=0.2706, I=0.4286）, 还是在种群水平上（P=88.80%, H=0.2759, I=0.4349）都表现出较高的遗传多样性。其中, 北京南口种群内遗传变异最大, 海南海口和甘肃兰州种群内遗传变异最小, 南方地区（云南、 湖北）小菜蛾种群遗传多样性明显高于北方地区（北京、 天津、 山东、 黑龙江、 甘肃）种群。据种群变异来源分析, 有5.66%的遗传变异来自种群间, 94.34%的变异来源于种群内（N_m=8.3399）, 不同地理种群间没有明显的遗传分化。本文有关小菜蛾不同地理种群基因流动和遗传变异的研究为小菜蛾抗药性的控制及田间种群的综合防治提供了有价值的分子生物学依据。     

喜马拉雅-横断山区钟花报春居群遗传多样性及遗传分化

应用简单序列重复区间(ISSR,Inter-simple sequence repeat)分子标记,对喜马拉雅．横断山区钟花报春(Primula sikkimensis)进行居群遗传分析。用10个ISSR引物对13个居群的254个个体进行扩增,共检出91条扩增片段,全部为多态带,总的多态位点百分率为100％。Shannon多样性指数(Ho)从0．2293到0．4016,居群水平上平均值(HPCP)为0．3211,物种水平上(Hsp)为0．5576。利用分子方差(AMOVA)软件分析,其结果为：在总的遗传变异中,有50．28％的遗传变异属于居群之间;用POPGENE计算出的遗传分化系数GST=0．4127,即居群间的分化变异占居群总遗传变异的41．27％,比AMOVA分析所得的结果偏低。居群间遗传距离变化范围从0．0780到0．4748,遗传一致度(I)的变化范围从0．6220到0．9250。居群间的基因流Nm=0．7114,相对低的基因流可能是维持钟花报春居群遗传分化的原因。这表明,喜马拉雅．横断山区钟花报春的13个居群具有很高的遗传多样性,并且居群间的分化也很大。     

7种川产淫羊藿属植物遗传多样性及亲缘关系的ISSR分析

利用ISSR分子标记对7种12居群的川产淫羊藿属植物进行遗传多样性及亲缘关系分析。结果发现23个ISSR随机引物共扩增194条清晰条带,其中169条具多态性,平均多态性位点比率为87.11%,有效等位基因数Ne=1.534 2,Nei基因多样性指数H=0.314 4,Shannon多样性指数I=0.469 7,表明物种间遗传多样性丰富。7种川产淫羊藿属植物间的遗传相似系数为0.653 2～0.748 9,聚类分析和主成分分析直观的显示出12份供试材料间的亲缘关系,并将其分为两类。表明ISSR分子标记技术可以用于川产淫羊藿属植物的遗传多样性和亲缘关系分析。     

A study of conservation genetics in Cupressus chengiana, an endangered endemic of China, using ISSR markers

ISSR markers were used to analyze the genetic diversity and genetic structure of eight natural populations of Cupressus chengiana in China. ISSR analysis using 10 primers was carried out on 92 different samples. At the species level, 136 polymorphic loci were detected. The percentage of polymorphic bands (PPB) was 99%. Genetic diversity (He) was 0.3120, effective number of alleles (Ae) was 1.5236, and Shannon's information index (I) was 0.4740. At the population level, PPB = 48%, Ae = 1.2774, He = 0.1631, and I = 0.2452. Genetic differentiation (Gst) detected by Nei's genetic diversity analysis suggested 48% occurred among populations. The partitioning of molecular variance by AMOVA analysis indicated significant genetic differentiation within populations (54%) and among populations (46%; P < 0.0003). The average number of individuals exchanged between populations per generation (Nm) was 0.5436. Samples from the same population clustered in the same population-specific cluster, and two groups of Sichuan and Gansu populations were distinguishable. A significantly positive correlation between genetic and geographic distance was detected (r = 0.6701). Human impacts were considered one of the main factors to cause the rarity of C. chengiana, and conservation strategies are suggested based on the genetic characters and field investigation, e.g., protection of wild populations, reestablishment of germplasm bank, and reintroduction of more genetic diversity.     

Close genetic relationship between cultivated and natural populations of common buckwheat in the Sanjiang area is not due to recent gene flow between them-An analysis using microsatellite markers

Natural populations of wild common buckwheat have been found growing adjacent to cultivated populations of common buckwheat. Gene flow between the cultivated and natural populations would be expected in such cases. To evaluate the amount of gene flow, two sets composed of a cultivated buckwheat population and an adjacent natural population of wild common buckwheat were chosen, one from Yanjing village in the Sanjiang area, which is presumed to be the original birthplace of common buckwheat, and one from Jinhe village, Yanyuan district of Sichuan province in China. The genotypes of 45 individuals from each population were examined at eight microsatellite marker loci to estimate the magnitude of gene flow between the cultivated and wild common buckwheat populations. The Bayesian method with a Markov chain Monte Carlo approach estimated that the magnitude of gene flow between the populations in the Sanjiang area at 0.002-0.008 was not significantly different from that found in Yanyuan district at 0.002-0.008. The gene flow between cultivated populations was higher, usually at 0.002-0.044 (exceptionally high at 0.255 between cultivated populations of Yanjing and Jinhe), than that found between a cultivated population and a natural population (0.002-0.008) or between two natural populations (0.002-0.003). Therefore, the genetic similarity found between the cultivated populations and natural populations observed in the Sanjiang area (Konishi et al., 2005) was not due to recent gene flow between them. This in turn suggests that the close genetic relationship found in the Sanjiang area may be due to the common ancestry of the natural populations and cultivated common buckwheat.     

特有珍稀濒危植物景东报春遗传多样性的ISSR分析(英文)

景东报春(Primula interjacens Chen)是一分布在中国云南中南部的稀有的、分布区狭窄的特有种。该种含2个变种:原变种景东报春(P.interjacens Chen var.interjacens),现存一个居群;和光叶景东报春(P.interjacens Chen var.epilosa C.M.Hu),有2个居群。本文用ISSR分子标记对景东报春现存的3个居群进行了遗传多样性分析。和我们最初的预计相反,尽管居群小、分布区狭窄,景东报春的遗传多样性却很高(在居群水平的多态位点率P=59.75％,基因多样性H_E=0.2368,Hpop=0.3459:在种的水平的多态位点率P=75.47％,遗传多样性H_T=0.3205,总的遗传多样性Hsp=0.4618)。推测异型花和杂交可能是维持高的遗传多样性的原因。Nei的遗传多样性水平(26.13％)和Shannon多样性指数(25.09％)显示居群间存在中度分化。尽管景东报春原变种和变种在形态上有区别,但用非加权配对算数平均法(UPGMA)聚类分析的结果表明,两者并没有明显的遗传分化,可处理为一个单一的分类单元。基于观察到的居群遗传信息,建议采取就地保护和迁地保护的保护措施。     

Genetic diversity of endangered Manglietia patungensis assessed by inter simple sequence repeat and sequence-related amplified polymorphism markers

Manglietia patungensis Hu is an endangered plant native to China. Knowledge of its genetic diversity and structure would aid its conservation. This study assessed nine natural populations of M. patungensis using two methods: inter simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) markers. Using 10 ISSR primer pairs, 334 bands were generated, and 10 SRAP primer pairs generated 276 bands. The percent of polymorphic bands (91.32% and 93.48%), Nei's genetic diversity (0.3448 and 0.3323), and Shannon's information index (0.5075 and 0.4935) revealed a high level of genetic diversity at the species level. Total heterozygosity was 0.3439 by ISSR and 0.3281 by SRAP. The mean heterozygosity was 0.2323 by ISSR and 0.2521 by SRAP. The coefficient of genetic differentiation among natural populations was 0.3245 by ISSR and 0.2316 by SRAP. These data indicated higher levels of genetic diversity of M. patungensis within, rather than among, populations. Estimates of gene flow among natural populations were 1.0411 and 1.0589, which implied a certain amount of gene exchange among populations. A Mantel test revealed no significant correlation between genetic and geographic distance. ISSR and SRAP markers are both effective for genetic diversity research in M. Patungensis. Based on these results, conservation of M. patungensis should be performed both in situ and ex situ.     

Highly differentiated populations of the narrow endemic and endangered species Primula cicutariifolia in China,revealed by ISSR and SSR

The perennial herb Primula cicutariifolia Pax is an endangered and endemic species with narrow distribution in eastern Anhui and Zhejiang provinces of China. In this study, the levels of genetic variation and the pattern of genetic structure in five natural populations of P. cicutariifolia were assessed by inter-simple sequence repeats (ISSR) and simple sequence repeat (SSR) markers. Both markers revealed that there was remarkably low genetic variation within populations (e.g., H_e = 0.19 and 0.18, for ISSR and SSR respectively) and high differentiation among populations (G_ST = 0.714 and 0.611; Φ_ST = 0.698 and 0.599, for ISSR and SSR respectively). The level of population genetic diversity was correlated to population size only detected by ISSR markers. The genetic structure of P. cicutariifolia may be explained by limited gene flow that was caused by habitat fragmentation and limited seeds and pollen dispersal ability, self breeding system and biennial life form. To protect and avoid disappearance of P. cicutariifolia, much more attentions should be paid to protect all the remnant populations and their habitats, and three management units, i.e. Tianmushan, Damodao, and Panan units, were proposed.     

基于ISSR数据探讨卷叶凤尾藓(Fissidens dubius P.Beauv.)遗传多样性

卷叶凤尾藓(Fissidens dubius P.Beauv.)是凤尾藓科凤尾藓属植物,该种分布广泛,形态变异强烈。为了解其遗传多样性及种群遗传结构特点,本研究利用ISSR分子标记对采集于浙江、福建、广西、四川、辽宁5个省区的卷叶凤尾藓14个自然种群的遗传多样性进行了评价。结果显示:筛选出的12对引物共扩增出259条清晰、重复性高的条带,其中多态性位点有248个,多态位点百分率为95.75%;种群总的Nei's基因多样性指数为0.2327,Shannon's信息指数为0.3701,说明卷叶凤尾藓遗传多样性水平较高;14个种群的遗传分化系数(Gst)为0.7078,种群间的基因流(Nm)为0.1864,表明大部分遗传变异(72.01%)存在于种群间,27.99%的遗传变异存在于种群内,即卷叶凤尾藓种群间遗传分化明显。基于ISSR数据的聚类分析表明,在遗传距离50为分组阈值处,14个种群可被分为6组(G1~G6):G1为来自于浙江省不同采集地点的8个种群(JHBS除外);G2由浙江金华北山种群(JHBS)组成;G3包括福建武夷山(WYS)和天宝岩种群(TBY);G4、G5、G6分别由广西龙胜县花坪种群(GX)、四川龙池种群(LC)、辽宁白石砬子保护区种群(BSLZ)组成,表明卷叶凤尾藓种群间的遗传分化主要由地理距离造成,种群内的遗传分化可能与其生境的异质性有关。     

Genetic diversity within and among populations of the endangered and endemic species Primula merrilliana in China

Primula merrilliana Schltr. is an endangered and narrowly-distributed endemic species of southern Anhui Province in China. In this study, the level of genetic variation and the pattern of genetic structure in six natural populations of P. merrilliana were assessed by using ISSR (inter-simple sequence repeats) markers. Based on ten primers, 137 clear and reproducible DNA fragments were generated, of which 109 were polymorphic. The statistical results indicated that there was a relatively low genetic diversity within populations, and a high genetic differentiation among populations (G_ST = 0.53, Φ_ST = 0.49). The level of population genetic diversity was correlated to habitat type and the gene flow (N_m) was low with only 0.45. The unexpected genetic structure of P. merrilliana may be explained by limited gene flow that was caused by habitat fragmentation and limited seeds and pollen dispersal ability, self-compatible breeding system and biennial life form.     

特有珍稀濒危植物景东报春遗传多样性的ISSR分析

景东报春(Primula interjacens Chen)是一分布在中国云南中南部的稀有的、分布区狭窄的特有种.该种含2个变种:原变种景东报春(P.interjacens Chen var.interjacens),现存一个居群;和光叶景东报春(P.interjacens Chen var.epilosa C.M.Hu),有2个居群.本文用ISSR分子标记对景东报春现存的3个居群进行了遗传多样性分析.和我们最初的预计相反,尽管居群小、分布区狭窄,景东报春的遗传多样性却很高(在居群水平的多态位点率P=59.75%,基因多样性HE=0.236 8,Hpop=0.345 9;在种的水平的多态位点率P=75.47%,遗传多样性HT=0.320 5,总的遗传多样性Hsp=0.4618).推测异型花和杂交可能是维持高的遗传多样性的原因.Nei的遗传多样性水平(26.13%)和Shannon多样性指数(25.09%)显示居群间存在中度分化.尽管景东报春原变种和变种在形态上有区别,但用非加权配对算数平均法(UPGMA)聚类分析的结果表明,两者并没有明显的遗传分化,可处理为一个单一的分类单元.基于观察到的居群遗传信息,建议采取就地保护和迁地保护的保护措施.     

Genetic variation within the endangered quillwort Isoëtes hypsophila (Isoetaceae) in China as evidenced by ISSR analysis

The genetic diversity of 56 individuals of Isoëtes hypsophila Hand.-Mazz. from China was investigated by ISSR. Twelve primers were screened from 65 primers, and a total of 119 DNA fragments were scored, of these, 82% were polymorphic bands, which indicated that high levels of genetic variation existed in the natural populations. Genetic diversity varied greatly among populations with the percentage of polymorphic band (PPB) values ranging from 8 to 35%. An analysis of molecular variance (AMOVA) was used to apportion the variation between regions, among populations within regions, and within populations. Results indicated that most of the variance (85%) occurred between Yunnan and Sichuan. The variances among populations within regions and within populations, however, were only 5 and 10%, respectively. In the among-population analysis, the larger part of genetic variation (77%) resided among populations, and less (23%) presented differences within populations. UPGMA cluster analysis showed that there was no distinct genetic differentiation between populations from Sichuan province. A number of causes including limited gene flow, genetic drift and inbreeding might have led to these observed genetic profiles of I. hypsophila.     

Original birthplace of cultivated common buckwheat inferred from genetic relationships among cultivated populations and natural populations of wild common buckwheat revealed by AFLP analysis

The genetic relationships among seven cultivated populations and eight natural populations of wild common buckwheat were analyzed using amplified fragment length polymorphism (AFLP). The genetic distance was estimated for each pair of the 15 populations based on the AFLP data, and a phylogenetic tree was constructed using the neighbor-joining (NJ) method based on the genetic distance. All the cultivated populations were grouped in a cluster. The natural populations were grouped into two clusters composed of (1) the Sanjiang group (three populations from eastern Tibet and one population from Adong village of Yunnan province) and (2) two populations from Yunnan province and two populations from Sichuan province. The Sanjiang group is more closely related to cultivated populations. These results indicate that the direct ancestor of common buckwheat was natural populations of wild common buckwheat from the Sanjiang area.