Randomly amplified polymorphic DNA analysis confirms the biotyping scheme of Porphyromonas gingivalis

The application of the arbitrarily primed PCR (AP-PCR) procedure to generate randomly amplified polymorphic DNA (RAPD) fingerprints for the study of the taxon Porphyromonas gingivalis was investigated. Nine human strains and seven animal strains of P. gingivalis as well as eighteen strains other than P. gingivalis were analysed. Four nanomer primers of random sequence were evaluated for their ability to distinguish genetic diversity. Three primers generated RAPD fingerprints that allowed the sixteen strains to be differentiated; two of the primers yielded species-specific markers, and two of the primers permitted biotype distinction. Cluster analysis of the RAPD fingerprints revealed two major phenetic groups that matched the human and animal biotypes. Our results indicate that AP-PCR (i) can generate strain-specific fingerprints, (ii) confirms genetic heterogeneity and the biotype grouping of the P. gingivalis taxon, and (iii) enables identification of potential genetic markers at the species, biotype and subtype levels and is thus a promising tool for bacterial systematics. Our results also underline the potential of AP-PCR for epidemiological studies of periodontal pathogens.