Bovine Mycoplasmas: Genome Size and Base Composition of DNA

SUMMARY: Within the order Mycoplasmatales guanine plus cytosine contents and genome sizes have been determined for 17 strains representing 15 bovine and two ovine species, subspecies or serogroups. The guanine plus cytosine contents were found to vary between 24.4 and 32.9%. The genome sizes were 4.0 to 5.6 × 108 daltons for 14 sterol-requiring strains and 0.99 to 1.1 × 109 daltons for three non-sterol-requiring strains. These results support earlier findings that members of the genus Acholeplasma (family Acholeplasmataceae) have genome sizes about twice those of the genus Mycoplasma (family Mycoplasmataceae).