为了研究蛇源裂头蚴种系发育关系,本研究对大王蛇裂头蚴湖南株的核糖体DNA内转录间隔区(ITS)进行扩增与测序,并对其基因序列进行比对后绘制种系进化树,分析蛇源裂头蚴与其它带科绦虫的种群遗传关系.结果显示,12个蛇源裂头蚴分离株ITS基因序列长度差异较小,为1 386 bp～1 404 bp;各分离株之间ITS-1和ITS-2差异分别为0.2％～1.3％和0.4％～2.2％,与GenBank中登录的其它带科绦虫相比,同源性均分别低于66.3％和52.1％.表明蛇源裂头蚴ITS基因序列在种内相对保守,种间差异较大,可以作为蛇源裂头蚴的分子遗传标记.分离株系统进化树显示,所有分离株与欧猬迭宫绦虫位于同一大分支,与其他带科绦虫得到了很好的鉴别.本研究为蛇源裂头蚴的鉴别诊断、分子流行病学调查等方面的研究奠定基础.%To explore the phylogenetic relationship of snake Sparganum,the gene sequence of internal transcribed spacers (ITS) in ribosomal DNA of snake Sparganum isolated from Hunan was amplified and sequenced.Then,ITS gene sequences alignment,and phylogenetic tree analysis were performed.The results showed that the lengths of the amplicated ITS gene sequences from the 12 snake Sparganums isolated from Hunan were 1 386 bp-1 404 bp,and the differences among the isolates were small.The differences of the corresponding gene sequences among the isolates were 0.2％-1.3％ (ITS-1) and 0.4％-2.2％ (ITS-2),respectively.The nucleotide similarities of Hunan isolates with Taeniidae reference strains on GenBank were lower than 66.3％ (ITS-1) and 52.1％ (ITS-2),which indicated the ITS gene sequences of the snake Sparganum were relatively conservative in the species,but the differences between species were great,and could be used as a genetic marker for species genetic variation of snake Sparganum.The constructed phylogenetic trees based on the ITS gene sequences revealed that the Hunan isolates and the Spirometra erinacei-europaei available in GenBank were clustered in the same clade,which indicated the Hunan isolates all belonged to the Spirometra erinacei-europaei.This study provides reference basis for identification,diagnosis,and molecular epidemiology survey of snake Sparganum.
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