Molecular taxonomy and phylogeny of entomopathogenic nematode species (Rhabditida: Steinernematidae) by RFLP analysis of the ITS region of the ribosomal DNA repeat unit

The ITS region of 19 isolates of the genus Steinernema Travassos, 1927 belonging to 17 species was PCR amplified. The resulting products were then digested with 17 different restriction endonucleases and the fragments generated were separated by agarose gel electrophoresis. Some enzymes yielded patterns which were highly diagnostic (e.g. Alu I, Dde I, Hha I and Hinf I) while others showed similar RFLP patterns for the majority of species (e.g. Hpa II). All of the species could be unequivocally identified using this method. A tree was constructed based on band sharing which resulted in clusters of species which exhibited similar morphological features.