共查询到20条相似文献，搜索用时 15 毫秒
1.
锦鸡儿属植物的遗传多样性及其种间关系 总被引：10，自引：3，他引：7
利用RAPD技术,对甘肃省自然分布的11种锦鸡儿属(CaraganaFabr.)植物的遗传多样性及其种间关系进行了研究。从34个10碱基随机引物中筛选出能产生稳定多态性标记的引物11个,共扩增出128个位点,主要集中在200~2000bp之间,其中104个表现出多态性,多态性比率高达81.25%;根据POPGENE32软件计算的Shannon多样性指数与Nei指数也较高,分别为0.3889和0.2517。说明锦鸡儿属植物具有丰富的遗传多样性,对环境变化的适应能力较强。应用UPGMA法进行聚类分析,结果表明,RAPD分析所反映的种间遗传关系与传统的形态学分类结果基本一致,但也有个别种的从属地位稍有变化。这说明还需要将分子标记的研究结果与形态学和其他方法结合起来进一步进行研究。 相似文献
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3.
耐旱苔藓植物DNA提取及优化RAPD、 ISSR反应体系的建立 总被引：1，自引：0，他引：1
耐旱苔藓植物常常单个个体矮小、生物量低,如何从细小的单个个体中有效提取总DNA是进一步开展居群遗传多样性研究的关键。本研究以古尔班通古特沙漠广泛分布的刺叶墙藓（Tortula desertorum）为对象,使用快速提取法、2×CTAB法及DNeasy plant mini kit试剂盒提取法等3种方法对刺叶墙藓单个个体的总DNA进行提取。结果表明,2×CTAB法提取的DNA纯度高,凝胶电泳显示无明显降解现象,适宜作为PCR扩增的模板。利用所提取的单个个体DNA为模板,建立了优化的RAPD、ISSR反应体系。 相似文献
4.
沙冬青根瘤菌结瘤基因nodA PCR-RFLP分析 总被引：2，自引：2，他引：0
利用结瘤基因nodA PCR-RFLP和nodA PCR产物序列分析技术,对36株分离自沙冬青根瘤菌菌株的共同结瘤基因nodA进行了遗传类型和系统发育关系分析。试验结果表明,36株根瘤菌nodA PCR-RFLP分析显示在80%的相似水平上聚为两个类群5个亚群;选取不同基因型代表菌株的nodA进行序列测定和系统发育关系分析表明,测试菌株CCNWNX0117、CCNWNX0068、CCNWNX0083、CCNWNX0062、CCNWNX0058与中慢生根瘤菌聚在一起,系统发育地位相近;测试菌株CCNWNX0089、CCNWNX0081、CCNWNX0064与中华根瘤菌聚在一起,有较高的序列相似性。本研究中nodA基因所揭示的沙冬青根瘤菌遗传多样性和系统发育关系说明沙冬青根瘤菌nodA基因遗传多样性较高,宿主结瘤范围较宽。 相似文献
5.
《湿地科学》2015,(5)
Chinese medaka(Oryzias sinensis),widely distributed in the plateau lakes,Yunnan Province,which was the indicative specie for the habitat quality of riparian zone in the wetland ecosystems and also was the key specie in the lake ecosystems,and also was one of the fishes who suffered the severe invasion of alien species.There,we investigated that the genetic diversity and population structure of the wild Chinese medaka by using inter-simple sequence repeat(ISSR)analysis.The samples(20 individuals in total)of Chinese medaka in three populations in the drainage area of Dian Lake were obtained.The 7 ISSR primers were picked out to assess the genetic diversity.The ISSR primers combinations revealed 82.69%polymorphism,among 52 genetic loci amplified.The sum of effective number of alleles and observed number of alleles were 1.492 4 and 1.826 9,respectively.The Shannon genetic diversity and Nei genetic diversity indexes of all the populations were 0.434 5 and 0.289 7,respectively.The gene differentiation(GST)was 0.198 9,and the gene flow(NM)was 2.013 2.The AMOVA demonstrated that only 6.65%of genetic variance came from inter-population,and 93.35%of genetic variance came from intra-population.Phylogenetic tree showed that 20 individuals from 3 populations were clustering mixed each other.Also,the principal coordinate analysis(PCA)supported the cluster analysis results.These results indicated that the genetic diversity of Oryzias sinensis was at the middle level,and there was no obvious genetic differentiation among the three populations of Oryzias sinensis. 相似文献
6.
内蒙古中西部草原区五种针茅的遗传多样性研究 总被引：1，自引：0，他引：1
利用RAPD（Random Amplified Polymorphism DNA, RAPD）分子标记技术,对内蒙古中西部草原区16个不同地理种群的五种针茅的遗传多样性及其种间关系进行了研究。从102个10碱基随机引物中筛选出28个有效引物,共扩增出389条带,多态性条带345条,占88.69%,说明针茅属植物具有丰富的遗传多样性,对环境的适应能力较强,PCA分析表明水热成为其地理分布的决定性因素。依据五种针茅的Jaccard相似系数所做的UPGMA聚类分析表明,大针茅和克氏针茅之间的遗传距离比较小聚为一类,它们与本氏针茅、短花针茅和小针茅间的遗传距离都比较大。 相似文献
7.
Diversity and genetic differentiation in Artemia species and populations detected by AFLP markers 总被引：1，自引：0，他引：1
Yi Sun Wen-Qin Song Yi-Cheng Zhong Run-Sheng Zhang Theodore J. Abatzopoulos Rui-Yang Chen 《International Journal of Salt Lake Research》1999,8(4):341-350
Amplified Fragment Length Polymorphism (AFLP) markers were successfully employed to analyze 15Artemia species and strains for genetic diversity. AFLP markers are extremely sensitive to even a small sequence variation. They
are stable and more polymorphic than RAPD. Twelve pairs of primer combinations were used to detect AFLP bands, of which 384
were polymorphic, and DNA fingerprintings were obtained by using silver staining. The polymorphism analysis leads us to the
following conclusions: 1.Artemia tibetiana seems to differentiate fromA. sinica. 2. The parthenogenetic populations from inland salt lakes could follow an evolutionary path that is different from that
of the coastal parthenogenetic populations. 相似文献
8.
霸王基因组RAPD优化条件的建立 总被引：9，自引：4，他引：5
实验以霸王20 d龄无菌籽苗为材料,使用CTAB法提取其基因组DNA,进行RAPD条件优化分析。通过单因子实验分别研究了Mg2+浓度、dNTPS浓度、Taq酶的浓度、引物浓度和模板DNA浓度对RAPD反应的影响,即在25 μL总反应体系中,Mg2+的适宜浓度为1.5~2.5 mmol\5L-1、dNTPs的适宜浓度为0.2~0.3 mmol\5L-1、随机引物的浓度以1.2 μmol\5L-1为宜、Taq酶的用量以2.0 U为佳、模板DNA的最适用量为50 ng。本研究的PCR扩增程序为94℃预变性8 min, 94℃变性1 min, 37℃退火1 min, 72℃延伸2 min,设40个循环,最后72℃保温6 min。 相似文献
9.
近年来,以对天然荒漠进行开垦和耕作为标志的人类活动加速了中国西北干旱荒漠区的绿洲化进程,但这种土地利用方式的改变对干旱荒漠土壤微生物群落特征的影响及其机理尚不清楚。本研究利用qPCR和Illumina Miseq高通量扩增子测序技术对新疆阿拉尔绿洲开垦5年的棉花田（FS）和毗邻的天然荒漠（ND）的土壤细菌、古菌和真菌群落的生物量、多样性和群落结构进行了对比研究,揭示了驱动荒漠土壤微生物群落结构演变的主要因子。结果表明：（1）荒漠开垦为农田后,土壤细菌和真菌群落的生物量显著增加,而古菌群落生物量显著降低;细菌群落多样性明显提高,古菌群落的Shannon多样性指数显著降低,而真菌群落多样性没有显著变化。（2）盐渍化荒漠具有不同于其他干旱荒漠的土壤微生物群落结构,开垦显著改变了其土壤细菌、古菌和真菌的群落结构。其中,放线菌门、绿弯菌门、酸杆菌门、螺旋体菌门和浮霉菌门细菌、乌斯古菌门和芽枝霉门真菌的相对丰度显著增加,而盐纳古菌门的相对丰度则显著降低。（3）土壤电导率（EC）、总有机碳（TOC）、全氮（TN）、全磷（TP）是影响细菌群落结构的关键因子;古菌群落结构的主要影响因子为植被盖度、地上生物量和丰富度、TP和AP;EC是影响真菌群落结构的关键因子。综上所述,盐渍化荒漠开垦后由于其原生植被群落、化学肥料的使用和土壤属性（EC、TP和AP）的改变不同程度地改变了荒漠土壤微生物群落特征。相对而言,细菌群落对土地利用方式的改变响应最为敏感,而古菌和真菌群落的多样性和结构则保持相对稳定。 相似文献
10.
This paper describes an efficient approach for computing the frequency response of seismic waves propagating in 2- and 3-D earth models within which the magnitude and phase are required at many locations. The approach consists of running an explicit finite difference time domain (TD) code with a time harmonic source out to steady-state. The magnitudes and phases at locations in the model are computed using phase sensitive detection (PSD). PSD does not require storage of time-series (unlike a fast Fourier transform), reducing its memory requirements. Additionally, the response from multiple sources can be obtained from a single finite difference run by encoding each source with a different frequency. For 2-D models with many sources, this time domain phase sensitive detection (TD–PSD) approach has a higher arithmetic complexity than direct solution of the finite difference frequency domain (FD) equations using nested dissection re-ordering (FD–ND). The storage requirements for 2-D finite difference TD–PSD are lower than FD–ND. For 3-D finite difference models, TD–PSD has significantly lower arithmetic complexity and storage requirements than FD–ND, and therefore, may prove useful for computing the frequency response of large 3-D earth models. 相似文献
11.
Kathleen R. Stoof-Leichsenring Nadine Bernhardt Luidmila A. Pestryakova Laura S. Epp Ulrike Herzschuh Ralph Tiedemann 《Journal of Paleolimnology》2014,52(1-2):77-93
Diatom diversity in lakes of northwest Yakutia (Siberia) was investigated by microscopic and genetic analysis of surface and cored lake sediments, to evaluate the use of sedimentary DNA for paleolimnological diatom studies and to identify obscure genetic diversity that cannot be detected by microscopic methods. Two short (76 and 73 bp) and one longer (577 bp) fragments of the ribulose 1,5-bisphosphate carboxylase/oxygenase (rbcL) gene, encoding the large subunit of the rbcL, were used as genetic markers. Diverse morphological assemblages of diatoms, dominated by small benthic fragilarioid taxa, were retrieved from the sediments of each lake. These minute fragilarioid taxa were examined by scanning electron microscopy, revealing diverse morphotypes in Staurosira and Staurosirella from the different lakes. Genetic analyses indicated a dominance of haplotypes that were assigned to fragilarioid taxa and less genetic diversity in other diatom taxa. The long rbcL_577 amplicon identified considerable diversification among haplotypes clustering within the Staurosira/Staurosirella genera, revealing 19 different haplotypes whose spatial distribution appears to be primarily related to the latitude of the lakes, which corresponds to a vegetation and climate gradient. Our rbcL markers are valuable tools for tracking differences between diatom lineages that are not visible in their morphologies. These markers revealed putatively high genetic diversity within the Staurosira/Staurosirella species complex, at a finer scale than is possible to resolve by microscopic determination. The rbcL markers may provide additional reliable information on the diversity of barely distinguishable minute benthic fragilarioids. Environmental sequencing may thus allow the tracking of spatial and temporal diversification in Siberian lakes, especially in the context of diatom responses to recent environmental changes, which remains a matter of controversy. 相似文献
12.
Katharina Dulias Kathleen R. Stoof-Leichsenring Luidmila A. Pestryakova Ulrike Herzschuh 《Journal of Paleolimnology》2017,57(1):51-66
The Arctic treeline ecotone is characterised by a steep vegetation gradient from arctic tundra to northern taiga forests, which is thought to influence the water chemistry of thermokarst lakes in this region. Environmentally sensitive diatoms respond to such ecological changes in terms of variation in diatom diversity and richness, which so far has only been documented by microscopic surveys. We applied next-generation sequencing to analyse the diatom composition of lake sediment DNA extracted from 32 lakes across the treeline in the Khatanga region, Siberia, using a short fragment of the rbcL chloroplast gene as a genetic barcode. We compared diatom richness and diversity obtained from the genetic approach with diatom counts from traditional microscopic analysis. Both datasets were employed to investigate diversity and relationships with environmental variables, using ordination methods. After effective filtering of the raw data, the two methods gave similar results for diatom richness and composition at the genus level (DNA 12 taxa; morphology 19 taxa), even though there was a much higher absolute number of sequences obtained per genetic sample (median 50,278), compared with microscopic counts (median 426). Dissolved organic carbon explained the highest percentage of variance in both datasets (14.2 % DNA; 18.7 % morphology), reflecting the compositional turnover of diatom assemblages along the tundra-taiga transition. Differences between the two approaches are mostly a consequence of the filtering process of genetic data and limitations of genetic references in the database, which restricted the determination of genetically identified sequence types to the genus level. The morphological approach, however, allowed identifications mostly to species level, which permits better ecological interpretation of the diatom data. Nevertheless, because of a rapidly increasing reference database, the genetic approach with sediment DNA will, in the future, enable reliable investigations of diatom composition from lake sediments that will have potential applications in both paleoecology and environmental monitoring. 相似文献
13.
传统村落景观基因信息链与自动识别模型构建——以陕西省为例 总被引：2，自引：0，他引：2
传统村落作为活的文化遗产,承载了大量历史记忆,是地域文化景观基因识别与模型构建研究的重要切入点。以陕西省71个国家级传统村落为例,基于景观基因理论建立陕西省传统村落景观基因识别体系,识别出陕西省传统村落景观基因特征;运用类型学原理和N级编码理论对景观基因进行编码,构建陕西省传统村落景观基因信息链并生成基因谱系;借鉴生物学中“胞-链-形”DNA碱基序列模型,提取出环境基因、建筑基因、农耕文化基因和宗族文化基因四个公共基因作为景观基因元（胞）,以村内道路系统作为基因链,构建传统村落景观基因DNA模型与自动识别模型,以此对传统村落的区位、类型、特征和文化基因进行自动识别。为传统村落景观基因信息有效传承与存储,以及乡村建设动态发展提供理论借鉴。 相似文献
14.
Food security in cold and arid regions in the world is threatened by stressful and unpredictable environments.The sus-tainable and economically viable solution for increasing stability of food productivity in cold and arid regions is genetic improvement of crops towards high resistance to abiotic stresses,mainly cold and drought resistance.It is often empha-sized that crop genetic improvement lies in exploiting the gene pools of the wild relatives of the crop plant.Wild barley,H.spontaneum,the progenitor of cultivated barley,is a selfing annual grass of predominantly Mediterranean and Irano-Turanian distribution that penetrates into desert environments where it maintains stable populations.Wild barley is also found in cold regions,such as in Tibet.The adaptation of wild barley to the arid region in Israel and Jordan,and the cold region in Tibet has accumulated rich genetic diversities for drought,salt,and cold resistances in wild barley,which is the genetic resource for barley and other crop improvement in arid and cold regions.These genetic diversities are revealed by allozymes,DNA-based molecular markers,and morphological and physiological traits of wild barley plants.Quantita-tive trait loci(QTLs) related to drought resistance were identified in wild barley via the QTL mapping approach.Drought resistance genes such as dehydrins,hsdr4,and eibi1 were identified in wild barley based on the candidate gene approach,gene differential expression approach,and molecular genetic approach,respectively.Genetics and genomics of wild bar-ley cold resistance have not been exploited yet,remaining a huge treasure for future crop improvement of cold resistance.Advanced backcross QTL analysis,the introgression libraries based on wild barley as donors,a QTL approach based on wide crosses using wild barley,and positional cloning of natural QTLs will play prevailing roles to help us understand the molecular control of cold and drought tolerance.Integration of QTL information into a breeding pipeline aimed at im-proving tolerance t 相似文献
15.
3种典型荒漠灌木内生固氮菌及固氮酶基因nifH多样性分析 总被引：1，自引：0，他引：1
具有特殊生境的内生固氮菌,对改善植物营养、增强植物抗逆性及群落稳定性具有重要作用,是一类潜力巨大、尚待开发的微生物资源。以新疆3种典型荒漠灌木多枝柽柳（Tamarix ramosissima）、黑果枸杞（Lycium ruthenicum）、盐穗木（Halostachys caspica）为材料,从根和枝条组织中分离筛选获得137个内生固氮菌菌株,采用16S rDNA PCR-RFLP、16S rDNA序列测定、BOXAIR-PCR指纹图谱、nifH PCR-RFLP等方法分析其遗传多样性及系统发育关系。结果表明：分离菌株经16SrDNA PCR-RFLP酶切图谱聚类划分为9个遗传类型。序列测定和系统发育分析显示,代表菌株分属于拉恩氏菌属（Rahnella）、假单胞菌属（Pseudomonas）、泛菌属（Pantoea）、芽孢杆菌属（Bacillus）、寡养单胞菌属（Stenotrophomonas）和申氏杆菌属（Shinella）,其中Rahnella为优势种群。一个测定菌株的16SrDNA序列同源性低于97%,提示可能为一个潜在的新种。BOXAIR-PCR分析优势种群的基因组结构特征,获得12种指纹图谱类型,显示出该种群具有丰富的基因组多样性。nifH PCR-RFLP分析分离内生固氮菌菌株固氮酶基因nifH的分子多态性,将其划分为3种基因型,体现了nifH具有高度保守性,同时在不同固氮微生物种群和菌株间也存在一定的多样性。研究结果丰富了固氮微生物物种资源库和基因库,对于内生固氮菌资源的保护和利用奠定了科学基础。 相似文献
16.
水松［Glyptostrobus pensilis（Stanunt.）K. Koch］为我国 I级重点保护野生植物之一,曾于珠江三角洲地区普遍生长。但由于近 50 a 来人类活动的强烈干扰,其野生种群和个体数量骤减,世界自然保护联盟（IUCN）已将水松评估为“极危”状态。文章以实测法进行野外调查,结果表明：广州市野生水松古树在近 5 a 间快速消亡,现仅存 8 个种群共 14 株个体,且半数处于生长不良或濒死状态;种群个体数量少,仅包括 1~4 株水松,无法进行自然更新;这些水松长期未得到科学合理的保护,如不采取有效保育措施,残酷的生存压力可能导致大部分种群的快速死亡。因此,在广州地区开展水松的就地和迁地保护、扩大种群的个体数量、开展水松的保护遗传学和监测人工林种群的遗传结构变化情况等研究,应成为目前保护和拯救本地区水松种群及其遗传多样性的必要策略。 相似文献
17.
正负地形可通过源汇过程对水、土资源进行再分配,影响山区的人口分布。获取正负地形数据,运用6个指标和多元逐步回归法,分析贵州高原山区正负地形特征及其对人口分布的影响。研究表明：①贵州高原山区的正负地形结构异质性明显。蚕食度、深切度、平均粗糙度比、形状指标、匀度指数、破碎度的平均值分别为1.07、371m、1.01、3.40、325和3.34,表明正地形被负地形蚕食明显、切入深度大,正、负地形的粗糙度基本相当,正负地形景观斑块呈现形状不规则、面积不均匀的破碎状态。6个正负地形指标中,匀度指数的变异性最大,变异系数为90.43%;平均粗糙度比的变异性最小,变异系数为1.06%;②贵州高原山区的人口分布不均匀性突出。人口累积达到40%时,累积面积百分比为14%;人口累积达到80%时,累积面积百分比约为50%;③6个正负地形指标中,蚕食度和深切度是影响人口分布的主要因素。蚕食度与人口密度呈正相关关系,深切度与人口密度呈负相关关系。研究成果为研究地形条件的人口影响提供补充,并为贵州高原山区人-地关系协调和土地可持续管理提供参考。 相似文献
18.
利用文山新一代天气雷达回波资料及PUP提供的雷达产品对2008年4月12日下午发生在文山州东北部的强对流降雹过程进行分析。结果表明：此次强对流风暴表现为一带状单体强降雹回波分裂为2条EN-W S向带状强对流回波带。在两条带状回波沿雷达径向的伸展方向又有多个强对流回波单体的生成发展。在强对流发展旺盛阶段一直有风向辐合和逆风区伴随。最大回波强度达61.2 dB z,≥50 dB z的强回波高度,最高≥10 km,回波垂直伸展高度大于13 km,最高≥16 km。在强对流风暴发展旺盛阶段,相应的垂直液态水含量和密度分别超过50kg/m2和10 kg/m2,最大达55 kg/m2。强降雹过程具有非常典型的冰雹云回波特征：＂V＂型缺口、回波悬垂结构、回波墙及有界弱回波区非常明显。 相似文献
19.
In order to provide a theoretical basis for the protection and development of T. ciliata germplasm resources, we studied the genetic diversity of T. ciliata by using SSR (Simple Sequence Repeat) primers to evaluate the genetic diversity of 192 T. ciliata germplasm samples from 24 populations of 5 provinces. DataFormater, Popgene, NTSYS, TFPGA and other software were used for genetic data conversion, genetic parameter estimation, dendrogram construction and genetic variation analysis. The results showed that: 1) a total of 17 alleles (Na) were detected in seven pairs of primers, with an average of 2.260 for each primer. Among them, the highest numbers of alleles (4) were detected in primers S11 and S422.The mean value of Nei’s genetic diversity index (H) was 0.4909, the mean value of Shannon information index (I) was 0.7321, and the mean value of polymorphic information content (PIC) was 0.5182. The mean expected heterozygosity (He) and observed heterozygosity (Ho) were 0.1055 and 0.4956, respectively. The Nei°s genetic distances of the populations ranged between 0.0002 and 2.6346, and the mean was 0.5477. The average genetic diversity level (H=0.1044) of the 24 populations was lower than that of the species (H=0.4909). 2) The genetic differentiation coefficients (Fst) varied from 0.2374 to 0.9148, with an average value of 0.7727. The mean of population gene flow (Nm) was 0.0735, indicating a low level of genetic exchange between populations, and suggesting that the genetic variation mainly came from within populations. 3) With the UPGMA method, the 24 populations were clustered into 3 groups at Nei’s genetic identity (0.99): the populations from Guizhou Province and Guangxi Zhuang Autonomous Region were clustered into one group, the populations from Hunan Province were in another group, and the populations from Hubei Province were in the third group. The Mantel test analysis showed a significant correlation between Nei’s genetic distance and geographic distance (r=0.6318, P=0.009?0.05). The genetic diversity of the 24 populations of T. ciliata was at a low level. Geographic isolation was the main reason for genetic differentiation among T. ciliata provenances. In the protection of germplasm resources of T. ciliata, emphasis should be placed on breeding genetic resources from the populations with higher genetic diversity (P14, for example). As for the populations with low genetic diversity, an ex-situ protection strategy as well as ecological and timber objectives, should be taken into account to maximize the conservation and utilization of the diversity of T. ciliata. 相似文献
20.
Agave cupreata and Agave potatorum are semelparous species distributed on dry tropical forests in south Mexico. Extraction of reproductive individuals for spirits production has caused a decline of wild populations and has raised concerns about their long-term conservation. We assess the degree of genetic erosion of exploited populations and provide population genetics baseline data for developing sustainable use strategies of these species. ISSRs (Inter Simple Sequence Repeats, dominant nuclear markers associated to microsatellites) were used to analyze five populations of each species throughout their distribution range. We found high levels of variation (P > 80%; H > 0.30) and moderate to high differentiation (A. potatorum θ = 0.120; A. cupreata θ = 0.172). Isolation by distance was significant in A. cupreata. Our data indicate that these species are not genetically eroded in general, and that they retain their historical patterns of diversity inside populations. Three genetically distinct populations are identified where conservation efforts should be a priority. Our results are discussed in relation to the in situ reinforcement of populations based on seeds propagation, in contrast to micropropagation practices that may threaten the genetic diversity of the species studied considering previous reports on genetic bottlenecks and inbreeding depression in Agave. 相似文献