College of Life Sciences, Capital Normal University Beijing, 100048, China.
School of Forestry, Experiment Center, Northeast Forestry University Haerbin, 150040, China.
Ecol Evol. 2014 Jun;4(12):2472-87. doi: 10.1002/ece3.1110. Epub 2014 May 20.
DNA barcoding has become a promising means for the identification of organisms of all life-history stages. Currently, distance-based and tree-based methods are most widely used to define species boundaries and uncover cryptic species. However, there is no universal threshold of genetic distance values that can be used to distinguish taxonomic groups. Alternatively, DNA barcoding can deploy a "character-based" method, whereby species are identified through the discrete nucleotide substitutions. Our research focuses on the delimitation of moth species using DNA-barcoding methods. We analyzed 393 Lepidopteran specimens belonging to 80 morphologically recognized species with a standard cytochrome c oxidase subunit I (COI) sequencing approach, and deployed tree-based, distance-based, and diagnostic character-based methods to identify the taxa. The tree-based method divided the 393 specimens into 79 taxa (species), and the distance-based method divided them into 84 taxa (species). Although the diagnostic character-based method found only 39 so-identifiable species in the 80 species, with a reduction in sample size the accuracy rate substantially improved. For example, in the Arctiidae subset, all 12 species had diagnostics characteristics. Compared with traditional morphological method, molecular taxonomy performed well. All three methods enable the rapid delimitation of species, although they have different characteristics and different strengths. The tree-based and distance-based methods can be used for accurate species identification and biodiversity studies in large data sets, while the character-based method performs well in small data sets and can also be used as the foundation of species-specific biochips.
DNA 条形码已成为鉴定所有生活史阶段生物的一种很有前途的手段。目前，基于距离和基于树的方法最广泛用于定义物种边界和揭示隐种。然而，没有普遍的遗传距离值阈值可用于区分分类群。或者，DNA 条形码可以采用“基于特征”的方法，通过离散的核苷酸替换来识别物种。我们的研究重点是使用 DNA 条形码方法来划分飞蛾物种。我们分析了 393 个属于 80 种形态学上可识别物种的鳞翅目标本，采用标准细胞色素 c 氧化酶亚基 I（COI）测序方法，并采用基于树、基于距离和基于诊断特征的方法来识别分类群。基于树的方法将 393 个标本分为 79 个分类群（物种），基于距离的方法将它们分为 84 个分类群（物种）。虽然基于诊断特征的方法在 80 个物种中仅发现了 39 个可识别的物种，但随着样本量的减少，准确率大大提高。例如，在天蛾科亚科中，所有 12 个物种都有诊断特征。与传统形态学方法相比，分子分类学表现良好。所有三种方法都可以快速划分物种，尽管它们具有不同的特征和不同的优势。基于树和基于距离的方法可用于在大数据集中进行准确的物种鉴定和生物多样性研究，而基于特征的方法在小数据集上表现良好，也可作为物种特异性生物芯片的基础。
