Partial nucleotide sequence similarity within species of Mycoplasma and Acholeplasma

The nucleotide sequence relationships between 18 species of Mycoplasma and 3 species of Acholeplasma were examined by solution DNA hybridization. Radiolabeled DNAs from strains representing 13 Mycoplasma and 2 Acholeplasma species were used as hybridization probes. The mycoplasmas were heterogeneous but displayed a low degree of conserved information of the order of 3 to 5% of the genome. However, several species within each genus showed 13 to 15% homology. There was no detectable homology between species from the two genera, and M. pneumoniae and M. neurolyticum appeared to be unrelated to any of the other Mycoplasma species or to each other. These results suggest that it may be possible to isolate genes common to most, if not all, Mycoplasma and Acholeplasma species.