Genetic relationships within the genus Prevotella analyzed by multilocus enzyme electrophoresis and DNA-DNA hybridization

The genetic diversity and relationships within the genus Prevotella were st udied by analyzing twenty-five strains by multilocus enzyme electrophoresis (MLEE) at nine metabolic enzyme loci and DNA-DNA hybridization. MLEE revea led a high genetic diversity with 25 electrophoretic types (ETs) for the 25 strains studied, a mean number of alleles per enzyme locus of 6.8 and a me an generic diversity per locus of 0.786. The index of association described by MAYNARD SMITH et al. (1933) revealed a clonal structure within the genu s Prevotella. A dendrogram generated by cluster analysis of a matrix of FTs showed that species like P. bivia, P. buccae, P. oris, P. oralis. P, nigre scens, and P. denticola form clusters that are consistent with DNA homologi es. However, strains identified as P. melaninogenica or P. loescheii by DNA -DNA hybridization did not constitute distinct subpopulations in MLEE. MLEE analysis demonstrated its high power in differentiating closely related st rains. It provides an alternative to 16S rRNA analysis for the study of phy logenetic relationships within the genus Prevotella, especially fur differe ntiating strains with high DNA homology or high rRNA homology.