两种毛首线虫核糖体DNA内转录间隔Ⅱ(rDNA ITS2)序列研究  

A taxonomic study on the sequence of the ribosomal second internal transcribed spacer of two Trichuris species

作　　者：斯健[1] 童新华[2] 

机构地区：[1]广州医学院第二附属医院广州510260 [2]重庆医科大学

出　　处：《中国人兽共患病学报》2009年第8期779-783,共5页Chinese Journal of Zoonoses

摘　　要：目的利用形态学鉴定方法结合rDNAITS2序列分析对取自重庆市动物园阿拉伯狒狒和松鼠猴的两种毛首线虫成虫进行分类学研究,分析其分类地位,并探讨毛首线虫属和其分子生物学分类体系可行性。方法先用形态学分类方法对两种毛首线虫定种,再提取其DNA扩增ITS2片段,通过测序确认两种毛首线虫ITS2序列,结合其它6种已知毛首线虫ITS2序列信息计算8种毛首线虫同一性和同源性并构建毛首线虫属同源树及分子种系发生树,探讨构建毛首线虫属分子生物学分类体系的可行性。结果形态学鉴定表明两种毛首线虫分别为T.cynocephalus皮翼毛首线虫和T.rhinopiptherox-ella sp.nov川金丝猴新种毛首线虫,二者形态学差异明显。获取两种ITS2序列连同6种已知ITS2做同一性分析,显示差异均在48.2%～62.7%之间,分属不同虫种;8种毛首线虫中T.leporis和T.skrjabini同源性最高,为91%;T.arvicolae和T.muris次之,为87%;提自松鼠猴的毛首线虫和T.suis为61%。T.ovis与T.leporis和T.skrjabini组同源性为65%,而提自阿拉伯狒狒的毛首线虫与提自松鼠猴的毛首线虫和T.suis组,为39%;构建同源树及分子种系发生树。结论本研究表明ITS2同一性分析能够对8个虫种进行有效甄别,作为辅助手段有望解决形态学分类中的同种异名问题。ITS2作为单一基因序列能部分反映8种毛首线虫同源性及分子进化中的关系,有助于探讨毛首线虫属的分子生物学分类体系的构建。A taxonomic study on the sequence of the ribosomal second internal transcribed spacer （rDNAITS2） of two Trichuris spp lollected from Papio hamadryas and Saimiri sciureus in zoological garden of Chongqing was made and their position in classification was analyzed in order to explore the possibility to construct a new taxonomic system with molecular biology for Trichuris species. Both the morphological identification and rDNAITS2 sequence analysis were carried out. In these ways, two Trichuris species, T. cynocephalus and T. rhinopiptheroccella sp. nov were identified by morphological method and their respective rDNAITS2 sequence were obtained. Afterwards, these two sequences were compared with the ITS2 sequences of other Turchuris species collected in GenBank database. It was found that obvious differences in morphology existed among these species. The homologous difference among these species was also apparent and appeared to be 48.2 % to 62.7 %. The homology between T. leporis and T. skrjabini was the highest one （91. % ） ; that between T. arvicolae and T. muris to be the next （87%） and that of the Trichuris species from S. sciureus and T. suis was 61%. In addition, the homology among T. ovis, T. leporis and T. skrjabini was 65 %, while that of Trichuris from P. hamadryas and S. sciureus and T. suis was 39 % respectively. After that the phylogenetic tree and the molecular development system were established which could be served as the evidence for the possibility to build a new taxonomic system of Trichuris species. From these observation it is evident that ITS2 sequence of Trichuris is a good candidate of genetic marker for the taxonomic study of Trichuris and it can be used to construct a new taxonomic system to reveal the realities of taxonomic relations of Trichuris.

关 键 词：毛首线虫属 分类学 同源性 内转录间隔区Ⅱ 

分 类 号：R383[医药卫生—医学寄生虫学]