16S ribosomal DNA sequence identities of beta-proteobacterial endosymbionts in three Crithidia species.

The 16S ribosomal DNA sequences of endosymbionts from the trypanosomatid protozoa (Crithidia spp.) are most homologous to that of Bordetella spp. This finding extends the polyphyletic origin of endosymbionts for the first time to the beta Proteobacteria. Biased base transitions and compensatory mutations of the symbionts' sequences that may contribute to their identity in the three Crithidia spp. are noted.