Small subunit rDNA phylogeny of Bacillidium sp (Microspora, Mrazekiidae) infecting oligochaets

Small subunit (SSU) rDNA has been sequenced from a microsporidium, identifi ed as a member of the genus Bacillidium obtained from an oligochaete. The l ength of the amplified PCR product was 1386 bp which is currently the longe st microsporidium SSU sequence known. Phylogenetic analysis using 28 micros poridia SSU sequences, using 3 different tree-building methods indicated th at Bacillidium sp. may be one of the earliest branches on the microsporidia tree. However, bootstrapping failed to give a high score (more than 50%) f or the position of Bacillidium sp. The branch leading to Bacillidium sp. wa s long, indicating that this species is not closely related to any of the o ther microsporidia so far studied by means of rDNA.