TY - JOUR AU - Hossain, Zarif AU - Sanzida, Nusrat Jahan AU - Akhand, Md Anwarul Azim AU - Ahmed, Md Sagir PY - 2021/06/29 Y2 - 2024/03/29 TI - DNA barcoding of threatened fishes of Bangladesh: DNA barcoding of threatened fishes of Bangladesh JF - Bioresearch Communications JA - Bioresearch Communications VL - 7 IS - 2 SE - Original Article DO - 10.3329/brc.v7i2.54373 UR - https://www.banglajol.info/index.php/BRC/article/view/54373 SP - 990-998 AB - <p>The ichthyofaunal diversity of Bangladesh is declining dramatically due to various anthropogenic factors. For authentic identification at species level, approximately 655 bp of the mitochondrial cytochrome c oxidase subunit I (COI) gene of 29 threatened fish species were amplified and a barcode dataset was generated. Among these species, 7% were categorized as Critically Endangered (CR), whereas 55% and 38% were categorized as Endangered (EN) and Vulnerable (VU), respectively. K2P genetic distances were evaluated and found to be increasing with higher taxonomic rank—1.01% to 13.09% within species and 17.42% to 41.57% between species with a DNA barcode gap of 4.33%. The average %GC content of the fish species was 44.7 ± 0.49. On the other hand, the %GC values for the 6 orders—Cypriniformes, Siluriformes, Synbranchiformes, Syngnathiformes, Perciformes and Osteoglossiformes were 44.8 ± 0.81, 45.6 ± 0.61, 44.8 ± 0.85, 47 ± 0.99, 46.3 ± 0.89, 47 ± 0.90, respectively. The %GC content was highest in the first codon followed by the second and third codons for both the individual species and the Orders (1<sup>st</sup>&gt;2<sup>nd</sup>&gt;3<sup>rd</sup>). It was also observed that the most synonymous mutations occur at the 3<sup>rd</sup> codon position followed by the 1st and the 2<sup>nd</sup> codons. Finally, genetic variations were identified in <em>Raiamas bola </em>(at position 101), <em>Ompok bimaculatus </em>(at position 396) and C<em>irrhinus reba </em>(at positions 108, 273, 310, 345, 420, 462, 495, 540 and 591) including 3 incidents of transversion (A instead of C). Thus, two different groups of <em>C. reba </em>emerged in the phylogram. This study, for the first time, focuses on COI based molecular characterization of the threatened fish species of Bangladesh and therefore, might work as a referral study for their authentic identification and <em>in-situ </em>conservation.</p><p>Bioresearch Commu. 7(2): 990-998, 2021 (June)</p> ER -