SEQUENCES OF THE 16S RIBOSOMAL-RNA GENES AND PHYLOGENY OF THE GOAT MYCOPLASMAS MYCOPLASMA-ADLERI, MYCOPLASMA-AURIS, MYCOPLASMA-COTTEWII ANDMYCOPLASMA-YEATSII

The nucleotide sequences of the 16S rRNA genes from the type strains o f four goat mycoplasmas, Mycoplasma adleri, Mycoplasma auris, Mycoplas ma cottewii and Mycoplasma yeatsii, were determined by direct solid-ph ase DNA sequencing, Polymorphisms were found in two of the 16S rRNA ge ne sequences, showing the existence of two different rRNA operons. Thr ee polymorphisms were found in M. adleri, and one was found in M. yeat sii. The sequence information was used for the construction of phyloge netic trees. M. adleri was included in the Mycoplasma lipophilum clust er within the hominis group. M. auris was comprised in the Mycoplasma hominis cluster of the hominis group, M. cottewii and M. yeatsii were found to be very closely related with only four nucleotide differences , and they grouped with Mycoplasma putrefaciens in the Mycoplasma myco ides cluster within the spiroplasma group, Sequencing of two field iso lates of M. cottewii and M. yeatsii, geographically distant from the t ype strains, showed that the 16S rRNA gene from the field isolate of M . cottewii was identical to the one from the type strain. The field is olate of M. yeatsii had only two nucleotide differences to the type st rain and these were present in only one of the two rRNA operons. Seque ncing of the 16S rRNA genes from two unidentified mycoplasma isolates from Nepal indicated that they should both be regarded as M. auris str ains.