Yu Yu-He
; Chinese Acad Sci, Inst Hydrobiol, Lab Taxonomy and Ecol Protozoa, State Key Lab Freshwater Ecol and Biotechnol, Wuhan 430072, Peoples R China
In this study, ISSR (inter simple sequence repeat) molecular markers Were used to clarify genetic relationships of five peritrichous ciliates: Carchesium. Polypinum., Epistylis chrysemydis, E. plicatilis, E. urceolata and Vorticella canilmada. From 34 primers, 13 polymorphic primers were selected and tested. The genetic distance values going from 0. 6667 to 1. 0000 among the Five species show the ISSR-PGR method has a high resolution. In the phylogenetic tree constructed with the unweighted pair group method using arithmetic averages (UPGMA), V. campanula was separated from other species firstly; C. polypinum and E. chrysemydis were closely related; in the group of Epistylis species, E. plicatilis and E. urceolata were first clustered together and then grouped with E. chrysemydis. These results were compared with the phylogenetic tree from the complete small subunit ribosomal RNA (SSrRNA) gene sequences. We found that: 1) TSSR primers can give the informative profiles in peritrichous ciliates; 2) C. polypinum. has a nearer relation with Epistylis than V. campanula. The colonial or solitary status might be a more important phylogenetic character within peritrichs than the characters of stalk and the myoneme; 3) E. urceolata shared closer relationship with E. plicatilis than E. claysemydis. The hollow nature of the stalk is a useful phylogenetic and taxonomic character in the genus Epistylis. This study demonstrated that ISSR-PGR method was a new useful method to reveal the relationships among related or similar species in ciliates.
