College of Fisheries, Ocean University of China, Qingdao 266003, China.
Mol Ecol Resour. 2011 Sep;11(5):820-30. doi: 10.1111/j.1755-0998.2011.03025.x. Epub 2011 May 19.
Oysters (family Ostreidae), with high levels of phenotypic plasticity and wide geographic distribution, are a challenging group for taxonomists and phylogenetics. As a useful tool for molecular species identification, DNA barcoding might offer significant potential for oyster identification and taxonomy. This study used two mitochondrial fragments, cytochrome c oxidase I (COI) and the large ribosomal subunit (16S rDNA), to assess whether oyster species could be identified by phylogeny and distance-based DNA barcoding techniques. Relationships among species were estimated by the phylogenetic analyses of both genes, and then pairwise inter- and intraspecific genetic divergences were assessed. Species forming well-differentiated clades in the molecular phylogenies were identical for both genes even when the closely related species were included. Intraspecific variability of 16S rDNA overlapped with interspecific divergence. However, average intra- and interspecific genetic divergences for COI were 0-1.4% (maximum 2.2%) and 2.6-32.2% (minimum 2.2%), respectively, indicating the existence of a barcoding gap. These results confirm the efficacy of species identification in oysters via DNA barcodes and phylogenetic analysis.
牡蛎（Ostreidae 科）具有高度的表型可塑性和广泛的地理分布，这对分类学家和系统发育学家来说是一个具有挑战性的群体。作为一种用于分子物种鉴定的有用工具，DNA 条形码可能为牡蛎的鉴定和分类提供巨大的潜力。本研究使用两个线粒体片段，细胞色素 c 氧化酶 I（COI）和大亚基核糖体（16S rDNA），评估基于系统发育和基于距离的 DNA 条形码技术是否可以鉴定牡蛎物种。通过对这两个基因的系统发育分析来估计物种之间的关系，然后评估种间和种内遗传差异。即使包括亲缘关系较近的物种，在分子系统发育中形成明显分化分支的物种在两个基因中都是相同的。16S rDNA 的种内变异性与种间差异重叠。然而，COI 的平均种内和种间遗传差异分别为 0-1.4%（最大值 2.2%）和 2.6-32.2%（最小值 2.2%），表明存在条形码间隙。这些结果证实了通过 DNA 条形码和系统发育分析进行牡蛎物种鉴定的有效性。
