Identification of a repetitive genomic sequence that is distributed among a select group of mycoplasmas.

Homologous DNA sequences common to different Mycoplasma species were identified and isolated using interspecies DNA hybridization. Specific homologies were found in three species of porcine mycoplasmas that were not detected in species from other animal hosts. Restriction fragments bearing these common sequences were isolated from genomic libraries of M. hyorhinis and M. hyopneumoniae, and DNA sequence analysis confirmed the sequence conservation predicted from hybridization studies. Multiple homology signals were detected by probing M. hyorhinis genomic digests with the isolated restriction fragments, suggesting that these common sequences are present in many copies in that species. The repetition of this sequence is, however, more limited in the other porcine mycoplasma chromosomes.