Department of Biology, Gendron Hall, Room 160, 30 Marie Curie, University of Ottawa, Ottawa, ON, K1N 6N5, Canada Canadian Museum of Nature, PO Box 3443 Stn "D", Ottawa, ON, Canada K1P 6P4.
Mol Ecol Resour. 2010 Jan;10(1):69-91. doi: 10.1111/j.1755-0998.2009.02725.x. Epub 2009 Jun 22.
Previous research on barcoding sedges (Carex) suggested that basic searches within a global barcoding database would probably not resolve more than 60% of the world's some 2000 species. In this study, we take an alternative approach and explore the performance of plant DNA barcoding in the Carex lineage from an explicitly regional perspective. We characterize the utility of a subset of the proposed protein-coding and noncoding plastid barcoding regions (matK, rpoB, rpoC1, rbcL, atpF-atpH, psbK-psbI) for distinguishing species of Carex and Kobresia in the Canadian Arctic Archipelago, a clearly defined eco-geographical region representing 1% of the Earth's landmass. Our results show that matK resolves the greatest number of species of any single-locus (95%), and when combined in a two-locus barcode, it provides 100% species resolution in all but one combination (matK + atpFH) during unweighted pair-group method with arithmetic mean averages (UPGMA) analyses. Noncoding regions were equally or more variable than matK, but as single markers they resolve substantially fewer taxa than matK alone. When difficulties with sequencing and alignment due to microstructural variation in noncoding regions are also considered, our results support other studies in suggesting that protein-coding regions are more practical as barcoding markers. Plastid DNA barcodes are an effective identification tool for species of Carex and Kobresia in the Canadian Arctic Archipelago, a region where the number of co-existing closely related species is limited. We suggest that if a regional approach to plant DNA barcoding was applied on a global scale, it could provide a solution to the generally poor species resolution seen in previous barcoding studies.
先前有关莎草科植物（Carex）条形码的研究表明，在全球条形码数据库中进行基本搜索，可能无法解决全球约 2000 种物种中的 60%以上。在这项研究中，我们采取了一种替代方法，从明确的区域角度探讨植物 DNA 条形码在莎草科植物谱系中的表现。我们从加拿大北极群岛这个明确界定的生态地理区域中，对部分提议的蛋白质编码和非编码质体条形码区域（matK、rpoB、rpoC1、rbcL、atpF-atpH、psbK-psbI）的功能进行了描述，以区分加拿大北极群岛的莎草属和薹草属物种。这一区域代表了地球陆地面积的 1%。我们的研究结果表明，matK 可以解决最多数量的物种（任何单一位点的物种分辨率达到 95%），当与 rbcL 联合使用时，在 UPGMA 分析中，除了一种组合（matK + atpFH）之外，所有组合都能达到 100%的物种分辨率。非编码区与 matK 一样具有变异性，或者比 matK 更具有变异性，但作为单一位点，它们的分类单元数量明显少于 matK 单独使用时的数量。当考虑到非编码区微观结构变异导致测序和比对困难时，我们的研究结果支持其他研究结果，即蛋白质编码区作为条形码标记更实用。在加拿大北极群岛，质体 DNA 条形码是鉴定莎草属和薹草属物种的有效工具，因为该地区共存的密切相关物种数量有限。我们建议，如果在全球范围内采用区域方法进行植物 DNA 条形码研究，可能会解决先前条形码研究中普遍存在的物种分辨率差的问题。
