基于线粒体COI和12S rDNA基因构建珠江河口鱼类DNA宏条形码数据库

Construction of DNA meta-barcode database of fish in Pearl River Estuary based on mitochondrial cytochrome COI and 12S rDNA gene

为建立珠江河口鱼类本底DNA条形码数据库,为珠江河口鱼类种类识别和多样性研究提供信息化基础,于2020—2021年在珠江河口采集鱼类样本251尾,测定了6目10科41属99种鱼类的219条线粒体COI基因5'端的652 bp序列和247条线粒体12S rDNA基因5'端的163~185 bp序列。同时,从GenBank数据库下载珠江河口鱼类COI序列165条和12S rDNA序列128条,共获得172种鱼类的384条COI序列与375条12S rDNA序列,初步构建了珠江河口鱼类条形码数据库。研究发现:COI序列种内平均遗传距离为0.20%,种间平均遗传距离为25.54%;12S rDNA序列种内平均遗传距离为0.12%,种间平均遗传距离为34.39%。基于COI基因的DNA条形码可形成明显的条形码间隙;而基于12S rDNA基因的DNA条形码不能形成明显的条形码间隙,11个物种(占总种类的6.4%)存在区分困难的情况。珠江河口鱼类DNA条形码数据库的建立,有利于推进该河口鱼类生态系统的环境DNA分析,并为珠江河口鱼类生物多样性的保护和种群动态监测提供可靠的技术支持。

In order to establish a DNA barcode background database of fish in the Pearl River Estuary and provide information basis for fish species identification and diversity research,we had collected 251 samples from the Pearl River Estuary from 2020 to 2021,and determined 652 bp fragments of mitochondrial cytochrome oxidase subunit I(COI)of 219 individuals and 163−185 bp fragments of mitochondrial 12s rDNA of 247 individuals of 99 species,10 families,41 genera,6 orders.Besides,we downloaded 165 COI sequences and 12812S rDNA sequences from GenBank database,and had obtained 384 COI sequences and 37512S rDNA sequences of 172 species of fish.The results show that the average intraspecific genetic distance of COI se-quence was 0.20%,and the average interspecific genetic distance was 25.54%.The average intraspecific genetic distance of 12S rDNA sequence was 0.12%,and the average interspecific genetic distance was 34.39%.The DNA barcode of COI gene could form an obvious barcode gap,but the DNA barcode based on 12s rDNA gene could not,and it was difficult to distinguish the 11 species(6.4%of the total species).The establishment of the DNA barcode database of fish in the Pearl River Estuary is conduc-tive to the environmental DNA analysis of the fish ecosystem in that area,providing reliable technical support for the protection of fish biodiversity and the monitoring of population dynamics in the Pearl River Estuary.