基于DNA条形码技术的珠江口春季鱼卵和仔稚鱼种类组成和分布特征的研究

采用线粒体COⅠ和12S rRNA基因片段作为DNA条形码，分析珠江口春季鱼卵和仔稚鱼种类组成和分布特征，并探究两种条形码在鱼卵和仔稚鱼种类鉴定中的适用性。研究共扩增样本391个，成功鉴定的鱼卵和仔稚鱼共7目25科42属60种（2种未鉴定到种）。其中，以鲈形目（Perciformes）种类和数量最多，种类数占比为51.6%，数量占比为47.91%；其次为鲱形目（Clupeiformes），种类数占比为25%，数量占比为34.56%。优势种10种，其中凤鲚（Coilia mystus）优势度最高，为0.071；棘头梅童鱼（Collichthys lucidus）最低，为0.014。COⅠ和12S rRNA基因片段扩增结果显示，鱼卵和仔稚鱼12S rRNA基因片段扩增成功率（95.60%）明显高于COⅠ基因（43.22%）。遗传距离和ABGD分析显示，COⅠ基因种内遗传距离为0～0.005（平均0.003），种间遗传距离为0.061～0.376（平均0.253），两者间存在明显的“条形码间隙”，ABGD划分结果与数据库比对结果一致；12S r RNA基因种内遗传距离为0～0.011（平均0...

Species composition and distribution characteristic of fish eggs and larvae based on DNA barcoding technology of the Zhujiang River Estuary in spring

In order to improve the success rate and accuracy of species identification of fish eggs and larvae, fish eggs and larvae samples collected from the Zhujiang River Estuary in spring were identified by DNA barcoding technology based on the mitochondrial COⅠand 12S rRNA genes. A total of 391 samples were amplified and 60 species in 7 orders, 25 families, 42 genera were successfully identified (2 species were not identified). Among them, Perciformes had the most species and quantity accounting for 51.6% and 47.91% respectively, followed by Clupeiformes with 25% and 34.56% respectively. There were 10 dominant species, among which Coilia mystus had the highest dominance of 0.071, Collichthys lucidus had the lowest dominance of 0.014. The amplification results of COⅠand 12S rRNA gene fragments showed that the success rate of 12S rRNA gene amplification in eggs and larvae (95.60%) was significantly higher than that of COⅠgene (43.22%). Genetic distance and ABGD analysis showed that the intraspecies genetic distance of COⅠ gene was 0?0.005 (average was 0.003), and the interspecific genetic distance was 0.061?0.376 (average was 0.253), and there was an obvious “barcode gap” between them. The intraspecific genetic distance of 12S rRNA gene was 0?0.011 (average was 0.007), and the interspecific genetic distance was 0.007?0.487(average was 0.283). which do not form a “barcode gap” between the interspecific and intraspecies genetic distances. The Bayesian phylogenetic tree based on COⅠ and 12S rRNA genes showed that all species could be clustered into independent branches and can be effectively distinguished. The above results show that both COⅠ gene and 12S rRNA gene can be used for the identification of most fish eggs and larvae, but the success rate of COⅠ gene amplification is low, and it is difficult to distinguish some closely related species of 12S rRNA gene. The combined use of the two genes can improve the success rate and accuracy of species identification of fish eggs and larvae.