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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。
OBJECTIVE: To study the taxonomic status of two species of T. gondii from the baboon and squirrel monkeys in the zoo of Chongqing Municipality using morphological identification and rDNAITS2 sequence analysis, and to analyze the taxonomic status of the two species and their molecular taxonomic classification System feasibility. METHODS: Two species of Trichinella were identified by morphological classification. ITS2 fragments were amplified by DNA. ITS2 sequences of two species of T. gondii were identified by sequencing. Based on the ITS2 sequence information of other 6 species of Trichinella, The homology and homology of T. gondii and the construction of homology trees and molecular phylogenetic trees of T. gondii were discussed in order to explore the feasibility of constructing the molecular biology classification system of T. gondii. Results Morphological identification showed that the two species of T. gondii were T.cynocephalus and T. rhinopiptherox-ella sp. Nov, respectively. The morphological differences between the two species were obvious. The identities of two ITS2 sequences and six known ITS2s were obtained, showing that the differences were between 48.2% and 62.7%, belonging to different species. The homology between T.leporis and T.skrjabini Highest at 91%; T.arvicolae and T. muris at 87%, 61% at T. trichocarpus and T. suis. The homology of T. ovis with T. leporis and T. skrjabini was 65% whereas that of T. trichocalyptus and T. suis populations from Arabidopsis monkey was 39%; construction of homologous Tree and molecular phylogenetic tree. Conclusions This study shows that ITS2 identity analysis can effectively discriminate eight species of insects, and as an auxiliary means it is expected to solve the problem of homonymy in morphological classification. ITS2, as a single gene sequence, can partially reflect the homology and molecular evolution of the eight species of T. gondii, which is helpful for the construction of the molecular biology classification system of T. gondii.