Ribosomal DNA sequences of Glugea anomala, G. stephani, G. americanus and Spraguea lophii (Microsporidia): phylogenetic reconstruction.

The microsporidian species Glugea anomala, G. stephani, G. americanus and Spraguea lophii were compared by using sequence data derived from their small subunit rDNA genes which were amplified by polymerase chain reaction and directly sequenced. These sequence data and published data of G. atherinae were analyzed and were used to infer a phylogenetic tree. The 5 microsporidian fish parasites appeared to be closely related. The higher sequence similarities demonstrated among G. anomala, G. stephani and G. atherinae suggest that these 3 parasites are in fact only 1 species of Glugea. Moreover, the higher sequence similarities between S. lophii and G. americanus support the transfer of the latter Glugea species into the genus Spraguea.