EVIDENCE FOR LATERAL TRANSFER AND RECOMBINATION IN OSPC VARIATION IN LYME-DISEASE BORRELIA

The ospC gene was amplified by the polymerase chain reaction from each of 76 Lyme disease Borrelia strains. Restriction fragment length poly morphism (RFLP) analysis demonstrated 33 distinct RFLP types; two addi tional RFLP types were identified from published ospC sequences. For e ach RFLP type, at least one ospC gene was sequenced and the degree of sequence relatedness examined by construction of an ospC gene tree. Th e genes were extremely diverse, with sequence identity ranging from 74 .4% to 99.0%; the majority of changes are localized within the central portion of the molecule. A comparison of ospC sequences suggests that recombination occurs frequently between ospC alleles; this genetic ex change is proposed to be mediated by lateral transfer of ospC sequence s. Evidence indicates that recombination occurs between ospC genes fro m the same Borrelia species (i.e. B. afzelii and B. garinii) as well a s between different Borrelia species (i.e. B. afzelii and B. garinii, B. burgdorferi and genogroup DN127).