Revealing the Hyperdiverse Mite Fauna of Subarctic Canada through DNA Barcoding

Although mites are one of the most abundant and diverse groups of arthropods, they are rarely targeted for detailed biodiversity surveys due to taxonomic constraints. We address this gap through DNA barcoding, evaluating acarine diversity at Churchill, Manitoba, a site on the tundra-taiga transition. Barcode analysis of 6279 specimens revealed nearly 900 presumptive species of mites with high species turnover between substrates and between forested and non-forested sites. Accumulation curves have not reached an asymptote for any of the three mite orders investigated, and estimates suggest that more than 1200 species of Acari occur at this locality. The coupling of DNA barcode results with taxonomic assignments revealed that Trombidiformes compose 49% of the fauna, a larger fraction than expected based on prior studies. This investigation demonstrates the efficacy of DNA barcoding in facilitating biodiversity assessments of hyperdiverse taxa.     

植物DNA条形码技术

DNA条形码技术是利用标准的、具有足够变异的、易扩增且相对较短的DNA片段在物种内的特异性和种间的多样性而创建的一种新的生物身份识别系统, 从而实现对物种的快速自动鉴定。尽管这一技术在理论上和具体应用上仍存在很多争论, 但DNA条形码概念自2003年由加拿大分类学家Paul Hebert首次提出后就在世界范围内受到了广泛关注。在植物类群中条形码的研究和应用尚处于探索阶段, 稍落后于对动物类群的研究, 这主要表现在: (1) DNA条形码的选择及其评价仍没有统一的标准; (2) 对类群较全面的形态分类学修订和植物DNA条形码研究的结合十分缺乏; (3) 以往研究在取样上尺度较大, 而对具体类群的研究较少, 一个科或一个属只用有限的种类作为代表, 同一种内的取样个体数量也不足, 这样虽然表面上看来利用选定的DNA条形码可以较容易地把代表物种区分开, 但实际上目前建议的植物DNA条形码(例如由生命条形码咨询委员会植物工作组最近提出的rbcL和matK)由于其分子进化速率较慢, 在种级水平上, 特别是对于那些经历了适应辐射或快速进化的属来说, 分辨率较低。而DNA条形码的应用主要集中在属内物种水平的鉴别, 因此只有针对具体类群进行探索研究, 发现进化速率较快、分辨率高且通用性好的条形码, 才可能为建立完整的条形码数据库起到积极有效的作用。     

植物DNA条形码技术

DNA条形码技术是利用标准的、具有足够变异的、易扩增且相对较短的DNA片段在物种内的特异性和种间的多样性而创建的一种新的生物身份识别系统,从而实现对物种的快速自动鉴定。尽管这一技术在理论上和具体应用上仍存在很多争论。但DNA条形码概念自2003年由加拿大分类学家Paul Hebert首次提出后就在世界范围内受到了广泛关注。在植物类群中条形码的研究和应用尚处于探索阶段,稍落后于对动物类群的研究,这主要表现在：（1）DNA条形码的选择及其评价仍没有统一的标准：（2）对类群较全面的形态分类学修订和植物DNA条形码研究的结合十分缺乏：（3）以往研究在取样上尺度较大,而对具体类群的研究较少,一个科或一个属只用有限的种类作为代表,同一种内的取样个体数量也不足,这样虽然表面上看来利用选定的DNA条形码可以较容易地把代表物种区分开,但实际上目前建议的植物DNA条形码（例如由生命条形码咨询委员会植物工作组最近提出的rbcL和matK）由于其分子进化速率较慢,在种级水平上,特别是对于那些经历了适应辐射或快速进化的属来说,分辨率较低。而DNA条形码的应用主要集中在属内物种水平的鉴别,因此只有针对具体类群进行探索研究,发现进化速率较快、分辨率高且通用性好的条形码,才可能为建立完整的条形码数据库起到积极有效的作用。     

DNA条形码研究进展

DNA条形码是应用有足够变异的标准化短基因片段对物种进行快速、准确鉴定的新的生物身份识别系统.2003年,加拿大Guelph大学Hebert等首次正式提出了DNA条形码概念,2004年成立了生物条形码联盟,目前有来自50个国家的两百多个组织成为其成员,2007年5月加拿大Guelph大学组建了世界上第一个DNA barcoding鉴定中心,2009年1月正式启动"国际生命条形码计划",中国科学院代表中国与加拿大、美国和欧盟共同为iBOL 4个中心节点.线粒体细胞色素C氧化酶基因COⅠ具有引物通用性高和进化速率快等优点,是理想的动物DNA条形码,不过,COⅠ在植物中应用效果较差,因此,核糖体ITS序列和质体rbcL、matK和trnH-psbA等序列也相继被引入植物的DNA条形码研究.虽然DNA条形码研究还处于起步阶段,面临巨大挑战,但是,越来越多的研究表明DNA条形码可以广泛应用于生物的分类和鉴定,是一种简便、高效、准确的物种鉴定技术,已经在动物、植物和微生物等研究中取得了显著成果,是生命科学领域发展最快的学科前沿之一.本文从DNA条形码的开发、应用、国内相关文献研究现状、DNA条形码面临的挑战以及发展前景等进行了综合分析,以期推动我国DNA条形码和分类学研究的发展.     

应用DNA条形码对植物标本的核查

DNA条形码主要目的是物种鉴定和新物种或隐存种的发现,而DNA条形码参考数据库是物种快速鉴定的重要基础。目前中国维管植物DNA条形码参考数据库正在建设之中,借助于公共数据库（NCBI）和初步建立的中国植物DNA条形码参考数据库,运用DNA条形码数据开展了植物标本鉴定的核查工作：（1）比较DNA序列信息与标本鉴定信息,从科、属、种级水平查找鉴定错误的标本;（2）基于有较好研究基础的DNA条形码参考数据库,开展未知标本的鉴定;（3）通过对标本核查的总结,提出DNA条形码参考数据库建设过程中的几点建议。     

藻类DNA条形码研究进展

DNA barcode,又称为DNA条形码,是指利用短的标准DNA序列的核苷酸多样性进行物种的鉴定和快速识别.目前该方法在动物分类研究中应用广泛,其中线粒体的细胞色素c氧化酶亚基1(cytochrome c oxidase subunit 1,COI或cox 1)基因中的约700bp长度的一段被用来作为标准DNA片段.在陆地植物条形码研究中,生命-植物条形码联盟会(Consortium for the Barcode of Life-Plant Working Group,CBOL-Plant Working Group)近期推荐将植物叶绿体中的两个基因片段rbcL+ matK作为初步的陆生植物条形码,此组合能在70％的程度上进行植物物种的鉴别.在海藻的分类研究中,DNA条形码的应用较少,已有的研究主要集中在硅藻、红藻和褐藻,尚没有学者明确提出适合藻类的DNA条形码.总结了能够作为藻类DNA条形码的序列特点、应用流程及分析方法,综述了DNA条形码在藻类中的研究现状和存在的问题,展望了藻类DNA条形码的应用前景.     

DNA条形码及其在生物多样性研究中的应用

DNA条形码是利用生物体内标准的、有足够变异的、易扩增且相对较短的DNA片段对物种进行快速准确鉴定的技术。自2003年DNA条形码相关概念提出以来广受关注,国内外相继开展了DNA条形码及信息系统建设研究,为DNA条形码技术的发展提供了坚实的研究基础和生物信息学分析平台。DNA条形码技术弥补了传统分类学的不足,为生物多样性研究提供了新的思路和方法。本文介绍了DNA条形码的产生与发展过程,国内外DNA条形码技术与信息系统建设研究进展,重点阐述了DNA条形码技术在物种鉴定、濒危物种保护、隐存种发现、生物多样性评估等研究领域中的应用。最后结合DNA条形码技术目前存在的问题,对其在相关研究领域的应用前景进行了展望。     

菌物DNA条形码技术原理与操作

DNA条形码技术是通过对1个较短目的基因的DNA序列进行分析从而进行物种鉴定的方法,它通过对1个或多个相关基因进行大范围的扫描,进而鉴定未知物种或者发现新种。当传统的分类学受到阻碍时,这种技术可以发挥其优势。相对于其他生物,菌物的生活史独特而复杂,这就使得对其进行的形态学鉴定要受到菌物自身生长发育时期的限制。国内外科学家对寻找适合于大多数菌物的标准DNA条码进行过探索,但还没有找到满足全部特征的基因片段。文中对DNA条形码技术的概念、原理依据、操作步骤和优缺点方面进行了介绍,并对DNA条形码技术在我国菌物研究方面的应用前景进行了展望。     

DNA条形编码技术在动物分类中的研究进展

DNA条形编码(DNA Barcoding)技术是一种新的生物分类方法,它是分子生物学和生物信息学相结合的产物。这一概念认为,就像在商店里扫描仪读取条形码那样,对地球上每一种生物也能通过快速分析其DNA中的一小段(线粒体细胞色素C氧化酶Ⅰ亚基,mt COI)加以识别。在最近3年里,该技术已成为生物分类学中研究的热点。理论上,DNA条形编码在生物分类鉴定中具有重要作用,但目前国际上对其的争论也不少。综述了DNA条形编码技术的产生、发展概况、原理与操作及其在动物分类中的应用,突出了该技术在寄生虫分类中应用的意义与可行性,并讨论了DNA条形编码在生物分类应用中可能存在的问题。     

Reassessment of Species Diversity of the Subfamily Denticollinae (Coleoptera: Elateridae) through DNA Barcoding

The subfamily Denticollinae is a taxonomically diverse group in the family Elateridae. Denticollinae includes many morphologically similar species and crop pests, as well as many undescribed species at each local fauna. To construct a rapid and reliable identification system for this subfamily, the effectiveness of molecular species identification was assessed based on 421 cytochrome c oxidase subunit I (COI) sequences of 84 morphologically identified species. Among the 84 morphospecies, molecular species identification of 60 species (71.4%) was consistent with their morphological identifications. Six cryptic and/or pseudocryptic species with large genetic divergence (>5%) were confirmed by their sympatric or allopatric distributions. However, 18 species, including a subspecies, had ambiguous genetic distances and shared overlapping intra- and interspecific genetic distances (range: 2.12%–3.67%) suggesting incomplete lineage sorting, introgression of mitochondrial genome, or affection by endosymbionts, such as Wolbachia infection, between species and simple genetic variation within species. In this study, we propose a conservative threshold of 3.6% for convenient molecular operational taxonomic unit (MOTU) identification in the subfamily Denticollinae based on the results of pairwise genetic distances analyses using neighbor-joining, mothur, Automatic Barcode Gap Discovery analysis, and tree-based species delimitation by Poisson Tree Processes analysis. Using the 3.6% threshold, we identified 87 MOTUs and found 8 MOTUs in the interval between 2.5% to 3.5%. Evaluation of MOTUs identified in this range requires integrative species delimitation, including review of morphological and ecological differences as well as sensitive genetic markers. From this study, we confirmed that COI sequence is useful for reassessing species diversity for polymorphic and polytypic species occurring in sympatric and allopatric distributions, and for a single species having an extensively large habitat.     

DNA条形码技术应用于人参鉴定

人参(Panax ginsengC.A.Meyer),被人们称为“百草之王”,是国内外常用的珍稀名贵中草药和高级滋补品,濒临灭绝,是急需进行资源保护的珍贵物种.随着中草药市场的国际化,由于利益的驱动,市场上伪混品屡见不鲜,对其正确鉴定就成为进行资源保护的首要条件.国内外学者对人参等药用植物资源的鉴定和可持续利用进行了广泛研究.DNA条形码(DNA barcoding)技术是分子鉴定的最新发展,即通过比较一段或几段通用DNA片段,对物种进行快速、准确的识别和鉴定,是近年来生物分类和鉴定的研究热点,在物种鉴定方面显示了广阔的应用前景.在分析传统的鉴定方法在适用范围和局限性的基础上,着重介绍了新兴的DNA条形码技术及其分析方法在人参鉴定上的特点及应用.     

鸡爪槭种下分类群的DNA条形码筛选

槭属鸡爪槭(Acer palmatum Thunb.)是北温带广泛分布的一类园艺观赏树种,由于频繁的种内杂交渐渗导致其种下分类群的形态性状特征趋同,致使传统的形态学分类难以准确鉴定,新兴的DNA条形码技术为快速、准确的鉴定鸡爪槭种下分类群提供了新的思路。本研究采用5个叶绿体DNA片段(rpl16、psbA-trnH、trnL-trnF、rbcL、matK)和核基因组ITS片段,运用PWG-distance和Tree-Building两种方法对鸡爪槭的8个分类群共32个个体进行DNA条形码分析。结果显示,单个叶绿体基因组片段(分辨率为0%~25%)或核rDNA ITS片段(12.5%)的分辨率较低,不同组合的叶绿体DNA片段(0%~62.5%)、叶绿体片段与核rDNA ITS片段(12.5%~50%)的分辨率则相对较高。其中,rpl16+psbA-trnH+trnL-trnF片段组合的分辨率最高(62.5%),较为符合DNA条形码快速、准确鉴定的要求,因此建议将其作为鸡爪槭种下分类群鉴定的DNA条形码。     

DNA条形码技术及其在保护生物学中的应用

物质文明及生活水平的提升为人类带来诸多好处的同时,也使人们越来越清晰地意识到保护生物多样性及生态系统稳定性的重大意义.DNA条形码技术作为现今生物分类学中重要的分子技术,可以快速准确地鉴定物种.多国科学家都在致力于对DNA条形码的研究,以便能共同组建数据库.将现有物种正确分类并期望用于发现新种,为生物的保护及生态系统的维护作出巨大贡献.细胞色素C氧化酶亚单位I(COI)是现在动物种类鉴定中最常用的基因之一.综述DNA条形编码技术的产生、原理、发展概况与操作及其在保护动物分类中的应用.阐明该技术在保护生物学中应用的意义与可行性,并讨论DNA条形编码在生物分类应用中可能存在的问题.     

动物DNA条形码之分析方法研究进展

DNA条形码是一段可用于物种鉴定的DNA序列。本文综述了近年来多种基于DNA条形码的分析方法及其在物种鉴定和隐存种发现中的应用,主要包括遗传距离法、进化树法、相似性比对法、诊断法和统计分类法等,旨在为这一技术的广泛应用提供参考。     

DNA Barcoding in Endangered Mesoamerican Groups of Plants

Among the applications of DNA barcoding for plant conservation is the identification of illegally traded endangered species from small samples or vegetative specimens. DNA barcoding offers an important tool for the phytosanitary authorities to identify species belonging to groups such as the bamboos and orchids, which command high prices in the horticultural trade. In this study we created a DNA barcode library for 20 endangered Orchidaceae species and 36 species of bamboo (Bambusoideae, Poaceae) distributed in Mexico. We applied several metrics to evaluate the efficiency of the barcodes matK and rbcL and, for bamboos, that of the plastid spacer psbI-K. Our results coincide with those of previous barcoding projects in which alone matK allowed for the identification of the most orchid species. For bamboos, the psbI-K spacer retrieved more polymorphic sites and in combination with matK we were able to identify bamboos to at least the generic level.     

A Retrospective Approach to Testing the DNA Barcoding Method

A decade ago, DNA barcoding was proposed as a standardised method for identifying existing species and speeding the discovery of new species. Yet, despite its numerous successes across a range of taxa, its frequent failures have brought into question its accuracy as a short-cut taxonomic method. We use a retrospective approach, applying the method to the classification of New Zealand skinks as it stood in 1977 (primarily based upon morphological characters), and compare it to the current taxonomy reached using both morphological and molecular approaches. For the 1977 dataset, DNA barcoding had moderate-high success in identifying specimens (78-98%), and correctly flagging specimens that have since been confirmed as distinct taxa (77-100%). But most matching methods failed to detect the species complexes that were present in 1977. For the current dataset, there was moderate-high success in identifying specimens (53-99%). For both datasets, the capacity to discover new species was dependent on the methodological approach used. Species delimitation in New Zealand skinks was hindered by the absence of either a local or global barcoding gap, a result of recent speciation events and hybridisation. Whilst DNA barcoding is potentially useful for specimen identification and species discovery in New Zealand skinks, its error rate could hinder the progress of documenting biodiversity in this group. We suggest that integrated taxonomic approaches are more effective at discovering and describing biodiversity.     

DNA Barcoding for Identification of Sugarcane Borers in China

Sugarcane borers are economically damaging insects with species that vary in distribution patterns both geographically and temporally, and vary based on ecological niche. Currently, identification of sugarcane borers is mostly based on morphological characters. However, morphological identification requires taxonomic expertise. An alternative method to identify sugarcane borers is the use of molecular data. DNA barcoding based on partial cytochrome c oxidase subunit 1 (COI) sequences has proven to be a useful tool for rapid and accurate species determination in many insect taxa. This study was conducted to test the effectiveness of DNA barcodes to discriminate among sugarcane borer species in China. Partial sequences of the COI gene (709 bp) were obtained from six species collected from different geographic areas. Results showed that the pairwise intraspecies genetic distance was < 0.02, whereas the interspecies genetic distance ranged from 0.117 to 0.182. Results from a neighbor-joining tree showed that the six sugarcane borer species were certainly separated. These results suggested that the partial COI sequences had high barcoding resolution in discriminating among sugarcane borer species. Our study emphasized the use of DNA barcodes for identification of the analyzed sugarcane borer species and represents an important step for building a comprehensive barcode library for sugarcane borers in China.     

Using DNA Barcoding to Study Hedgehog Community in Egypt

Russian Journal of Genetics - This is the first study of analyzing and identifying the hedgehog community in Egypt using a molecular marker especially it includes the Four-toed Hedgehog which is...