Department of Zoology, University of Dhaka, Dhaka 1000, Bangladesh.
Department of Genetic Engineering and Biotechnology, University of Dhaka, Dhaka 1000, Bangladesh.
Gene. 2019 Feb 5;684:53-57. doi: 10.1016/j.gene.2018.10.048. Epub 2018 Oct 22.
The mitochondrial DNA gene cytochrome oxidase subunit I (COI) has been adopted as a global bioidentification system for animals. This study represents the comprehensive molecular identification of small indigenous fish species (SIS) of Bangladesh assessed by DNA barcoding. DNA barcodes were generated from 81 SIS species belongs to the orders Clupeiformes, Cypriniforms, Siluriformes, Perciformes, Synbranchiformes, Beloniformes and Tetraodontiformes representing 55 genera and 24 families. For all the samples, %G were significantly lowered compared to other nucleotides and %GC compared to %AT. Also, a significantly lowered GC content was observed in second and third codon position compared to the first codon position in all samples. The average Kimura two-parameter (K2P) distances within genera, families, and orders were 15.83%, 19.14%, and 25.07%, respectively. The minimum and maximum K2P distance based genetic divergences were 0.19% and 57.14% respectively. Members of Cypriniformes, Siluriformes, and Perciformes were clustered separately in the neighbour-joining (NJ) tree. Nucleotide composition, GC distribution across codon positions, K2P distance, genetic divergence, and phylogenetic analyses reveal that these freshwater SIS fishes are genetically very diverse. Along with morphological data, we have confirmed the existence of seven new records of SIS fishes in Bangladesh using such barcode approach. These findings suggest that fishes can be discriminated using these barcode data without any confusion.
线粒体 DNA 基因细胞色素氧化酶亚基 I（COI）已被采用为动物的全球生物识别系统。本研究代表了通过 DNA 条形码评估的孟加拉国小型本地鱼类物种（SIS）的综合分子鉴定。DNA 条形码是从属于鲱形目、鲤形目、鲇形目、鲈形目、合鳃目、鳗鲡目和鲀形目的 81 个 SIS 物种产生的，代表 55 个属和 24 个科。对于所有样本，与其他核苷酸相比，%G 显著降低，与%AT 相比，%GC 降低。此外，与所有样本的第一密码子位置相比，第二和第三密码子位置的 GC 含量明显降低。属内、科内和目内的平均 Kimura 双参数（K2P）距离分别为 15.83%、19.14%和 25.07%。基于 K2P 距离的最小和最大遗传分歧分别为 0.19%和 57.14%。鲱形目、鲇形目和鲈形目的成员分别在邻接法（NJ）树中聚类。核苷酸组成、密码子位置的 GC 分布、K2P 距离、遗传分歧和系统发育分析表明，这些淡水 SIS 鱼类在遗传上非常多样化。结合形态学数据，我们使用这种条码方法在孟加拉国确认了 7 种新记录的 SIS 鱼类的存在。这些发现表明，可以使用这些条码数据而不会混淆地识别鱼类。
