A PHYLOGENETIC ANALYSIS OF BORRELIA-BURGDORFERI SENSU-LATO BASED ON SEQUENCE INFORMATION FROM THE HBB GENE, CODING FOR A HISTONE-LIKE PROTEIN

We describe a phylogenetic investigation of Borrelia burgdorferi sensu late, the causative agent of Lyme disease, based on a DNA sequence an alysis of the hbb gene, which encodes protein HBb, a member of the fam ily of histone-like proteins, Because of their intimate contact with t he DNA molecule, these proteins are believed to be fairly conserved th rough evolution. In this study we proved that the hbb gene is suitable for phylogenetic inference in the genus Borrelia, The hbb gene, which is 327 bp long and encodes 108 amino acids, was sequenced for 39 stra ins, including 37 strains of B. burgdorferi sensu late, 1 strain of Bo rrelia turicatae, and 1 strain of Borrelia parkeri. Genetic variabilit y was determined at the sequence level by computational analysis, Brie fly, 81 substitutions were scored at the DNA level, Only 25 of these s ubstitutions were responsible for amino acid substitutions at the tran slational level. The signature region for bacterial histone-like prote ins was found in hbb, Although variable at the nucleotide level, it wa s highly conserved at the deduced amino acid level, A phylogenetic tre e for the genus Borrelia that was generated from multiple sequence ali gnments was consistent with previously published data derived from DNA -DNA hybridization and multilocus enzyme electrophoresis analyses, The subdivision of B. burgdorferi sensu late into five species (B. burgdo rferi sensu stricto, Borrelia garinii, Borrelia afzelii, Borrelia japo nica, and ''Borrelia andersonii'') and at least four genomic groups (g roups PotiB2, VS116, CA2, and DN127) was confirmed.