强壮粗体虫的线粒体基因组及棘头虫的系统发育研究

THE CLONING OF THE MITOCHONDRIAL GENOME OF HEBESOMA VIOLENTUM(ACANTHOCEPHALA) AND THE PHYLOGENETIC ANALYSIS OF ACANTHOCEPHALANS

通过长距离PCR方法,克隆了鳜(Siniperca chuatsi Basilewsky)肠道内寄生虫——强壮粗体虫(Hebesoma violentum Van Cleave)线粒体基因组全长序列,共13393 bp(GenBank登录号:KC415004),有36个基因,其中蛋白编码基因12个,核糖体基因2个,tRNA22个。所有基因均由线粒体基因组同一条链按同一个方向转录。利用该线粒体基因组和已经报道的一些轮虫纲种类的线粒体基因组序列,构建了棘头虫和轮虫的系统发育树。系统发育研究表明:包括强壮粗体虫、隐藏新棘虫Pallisentis celatus(Van Cleave)和Paratenuisentis ambiguous(Van Cleave)在内的始新棘头虫纲(Eoacanthocephala)与古棘头虫纲(Palaeacanthocephala)亲缘关系较近,聚为一枝后再与原棘头虫纲(Archiacanthocephala)聚在一起;棘头虫与双巢类轮虫(Bdelloid)亲缘关系最近,聚为一枝,然后再与单巢类轮虫(Monogonont)聚在一起,表明棘头虫和轮虫具有较近的亲缘关系。

The acanthocephalan Hebesoma violentum Van Cleave was collected from the intestine of Siniperca chuatsi Basilewsky, which were captured in the Liangzi Lake of Hubei Province, China. Using long PCR we cloned the entire mitochondrial （mt） genome sequence of H. violentum（13,393 bp） （GenBank accession No. KC415004）. The genome consists of 36 genes including 12 protein-coding genes, 22 transfer RNAs （tRNAs） and 2 ribosomal RNAs （rRNAs）, which was consistent with previous reports about mt genomes of other acanthocephalan species. All genes in the mt genome were encoded on one strand and transcribed in the same direction. The phylogenetic analysis of the mt genomes of acanthocephalans, rotifers and others indicated that the class Eoacanthocephala, containing Pallisentis celatus Van Cleave, Hebesoma violentum Van Cleave and Paratenuisentis ambiguus Van Cleave, was closely related to Palaeacan-thocephala which was then correlated with the class Archiacanthocephala. It is obvious that acanthocephalans are closely related to a clade containing bdelloids which were then correlated with the clade containing monogononts. Fur-ther phylogenetic analysis of rotifers in the Seisonidea and acanthocephalans in the Polyacanthocephala will provide insights into the phylogenetic relationship between the major taxa of rotifers and/or acanthocephalans, as well as be-tween these two groups.