Pentinsaari Mikko, Hebert Paul D N, Mutanen Marko
Department of Biology, University of Oulu, Oulu, Finland.
Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada.
PLoS One. 2014 Sep 25;9(9):e108651. doi: 10.1371/journal.pone.0108651. eCollection 2014.
With 400 K described species, beetles (Insecta: Coleoptera) represent the most diverse order in the animal kingdom. Although the study of their diversity currently represents a major challenge, DNA barcodes may provide a functional, standardized tool for their identification. To evaluate this possibility, we performed the first comprehensive test of the effectiveness of DNA barcodes as a tool for beetle identification by sequencing the COI barcode region from 1872 North European species. We examined intraspecific divergences, identification success and the effects of sample size on variation observed within and between species. A high proportion (98.3%) of these species possessed distinctive barcode sequence arrays. Moreover, the sequence divergences between nearest neighbor species were considerably higher than those reported for the only other insect order, Lepidoptera, which has seen intensive analysis (11.99% vs up to 5.80% mean NN divergence). Although maximum intraspecific divergence increased and average divergence between nearest neighbors decreased with increasing sampling effort, these trends rarely hampered identification by DNA barcodes due to deep sequence divergences between most species. The Barcode Index Number system in BOLD coincided strongly with known species boundaries with perfect matches between species and BINs in 92.1% of all cases. In addition, DNA barcode analysis revealed the likely occurrence of about 20 overlooked species. The current results indicate that DNA barcodes distinguish species of beetles remarkably well, establishing their potential to provide an effective identification tool for this order and to accelerate the discovery of new beetle species.
甲虫（昆虫纲：鞘翅目）有40万种已知物种，是动物界中最多样化的目。尽管目前对其多样性的研究是一项重大挑战，但DNA条形码可能为其鉴定提供一种实用的标准化工具。为评估这种可能性，我们通过对1872种北欧物种的细胞色素氧化酶亚基I（COI）条形码区域进行测序，首次全面测试了DNA条形码作为甲虫鉴定工具的有效性。我们研究了种内差异、鉴定成功率以及样本量对物种内和物种间观察到的变异的影响。这些物种中有很大比例（98.3%）拥有独特的条形码序列阵列。此外，近缘物种之间的序列差异明显高于另一个经过深入分析的昆虫目——鳞翅目（平均近缘差异为11.99%，而鳞翅目最高为5.80%）。尽管随着采样量的增加，最大种内差异增加，近缘物种之间的平均差异减小，但由于大多数物种之间的序列差异较大，这些趋势很少妨碍通过DNA条形码进行鉴定。生物条形码数据系统（BOLD）中的条形码索引号系统与已知的物种界限高度吻合，在所有案例中，92.1%的物种与BINs（生物条形码索引号）完全匹配。此外，DNA条形码分析揭示了大约20种可能被忽视的物种的存在。目前的结果表明，DNA条形码能够很好地区分甲虫物种，证明了其有潜力为该目提供一种有效的鉴定工具，并加速新甲虫物种的发现。
