Classification of the F38 group of caprine Mycoplasma strains by DNA hybridization

Representatives of groups of mycoplasmas which have antigens in common with Mycoplasma mycoides (as demonstrated by different serological tests) were compared by nucleic acid hybridization. Determinations of DNA homology were performed by filter hybridization as well as hybridization in solution; no differences were revealed between the two methods. Genetic relatedness was not demonstrated between M. primatum and strain F38. The antigenic similarities between strain F38 and the type strain of M. primatum (HRC292) may be due to common epitopes. DNA from strain F38 hybridized with DNA from M. capricolum (California kid) to 80%, but only to about 40% with the two M. mycoides subspecies, a result which can justify the classification of the F38 group as a variant of M. capricolum. The representative strain of bovine serogroup 7 of Leach was equally distant from F38, M. capricolum and the two subspecies of M. mycoides (approximately 60% hybridization).