Sequence variation of Ribosomal DNA Internal Transcribed Spacer 1 of Hyriopsis cumingii from the Five Freshwater Lakes of China

Abstract

对我国五大淡水湖:鄱阳湖、洞庭湖、太湖、巢湖、洪泽湖,鄱阳湖内包括进贤、余干、珠湖、都昌、湖口、永修,合计10个群体三角帆蚌78个个体核糖体DNA基因转录间隔子ITS-1进行PCR扩增、序列测定,获得78条长度为430 bp的同源序列.同源基因序列分析显示,五大淡水湖10个群体三角帆蚌78条ITS-1序列片段,G+C的含量都明显高于A+T的含量.鄱阳湖三角帆蚌的核苷酸多态性指数最高,而巢湖的核苷酸多样性指数最低.基于ITS-1序列片段的遗传距离表明,鄱阳湖内六个点群体间遗传距离很小,在0.0071到0.0092之间.五大湖间三角帆蚌群体遗传距离较远,在0.0752到0.1381之间,ITS-1序列片段构建系统树显示,鄱阳湖6个群体聚在了一起为单独一支,并与巢湖群体亲缘关系相近.洞庭湖群体和洪泽湖群体亲缘关系相近,单独为一支.太湖群体从鄱阳湖、巢湖群体分离开来,单独为一支.;The internal transcribed spacer 1 (ITS-1) was amplified from Hyriopsis cumingii in the five large lakes of China: LakePoyang, Lake Dongting, Lake Taihu, Lake Chaohu and Lake Hongze, and 430bp lengths of homological fragments of the ITS-1 wassequenced from 78 individuals of ten stocks. The homological fragment analysis showed that the average contents of G+C wereobviously higher than that of A+T. The nucleotide diversity of ITS of Lake Poyang was the highest, while that of Lake Chaohu wasthe lowest. The genetic distances among the six stocks from Lake Poyang were very near, which was from 0.0071 to 0.0092. Thegenetic distance among the five stocks from five large lakes were relatively far, which was from 0.0752 to 0.1381. The phylogenetictree of ITS-1 built with MEGA 3.1 showed that the six stocks from Lake Poyang clustered together independently, and had a relativecloser relationship with Lake Chaohu. The phylogenetic relationship between Lake Dongting and Lake Hongze was relatively closeand clustered independently. The stocks of Lake Taihu was an independent one, which diverged from those of Lake Pongyang andChaohu.