Specie identification from single amphistome eggs by PCR-RFLP based on ribosomal DNA ITS-2 marker

本研究的目的是首先描述3种端口类寄生虫（Calciforon calciforum，Orthocococophorus streptocococophorum和Homalogaster palpalpium）的ITS 2序列差异程度，其次评估PCR-RFLP方法用于单卵寄生虫的种鉴定。C. ITS 2序列长284 bp。calcohoronm和O.链球菌属（Streptocococcus）285 bp;苍白3种虫的ITS 2序列共有19个变异位点，包括1个gap，种间序列差异为4.2- 5.3%。构建了这三个物种ITS 2序列的限制性内切酶图谱。虽然存在一些常见的限制性内切酶的几个位点，但可以通过Acc II，Mfl I和Hha I的位置将这三种端口动物彼此区分开。结果表明，ITS 2序列可作为PCR-RFLP技术鉴定这3个种的单卵的DNA标记。

The purpose of this study is first to describe the extent of ITS2 sequence difference among 3 species of amphistomes, namely Calicophoron calicophorum, Orthocoelium streptocoelium and Homalogaster paloniae, and secondly to assess PCR-RFLP method for the species identification of single eggs of the parasites. The length of ITS2 sequence was 284bp in C. calicophoronm and O. streptocoelium, and 285bp in H. paloniae. The ITS2 sequences of the three species contained 19variable sites including one gap and sequence difference between species was 4.2-5.3%. Restriction maps were constructed for ITS2 sequences of the three species. Although several sites existed for a number of common restriction endonucleases, the three species of amphistomes could be distinguished from each other by the position of Acc II, Mfl I and Hha I. These results suggest that ITS2 sequence should be useful as DNA marker for species identification of single eggs of the three species using PCR-RFLP technique.