A phylogenomic and molecular marker based proposal

Authors: Mobolaji Adeolu Radhey S Gupta

Publish Date: 2014/04/18

Volume: 105, Issue: 6, Pages: 1049-1072

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Abstract

The genus Borrelia contains two groups of organisms the causative agents of Lyme disease and their relatives and the causative agents of relapsing fever and their relatives These two groups are morphologically indistinguishable and are difficult to distinguish biochemically In this work we have carried out detailed comparative genomic analyses on protein sequences from 38 Borrelia genomes to identify molecular markers in the forms of conserved signature inserts/deletions CSIs that are specifically found in the Borrelia homologues and conserved signature proteins CSPs which are uniquely present in Borrelia species Our analyses have identified 31 CSIs and 82 CSPs that are uniquely shared by all sequenced Borrelia species providing molecular markers for this group of organisms In addition our work has identified 7 CSIs and 21 CSPs which are uniquely found in the Lyme disease Borrelia species and eight CSIs and four CSPs that are specific for members of the relapsing fever Borrelia group Additionally 38 other CSIs in proteins which are uniquely found in Borrelia species also distinguish these two groups of Borrelia The identified CSIs and CSPs provide novel and highly specific molecular markers for identification and distinguishing between the Lyme disease Borrelia and the relapsing fever Borrelia species We also report the results of average nucleotide identity ANI analysis on Borrelia genomes and phylogenetic analysis for these species based upon 16S rRNA sequences and concatenated sequences for 25 conserved proteins These analyses also support the distinctness of the two Borrelia clades On the basis of the identified molecular markers the results from ANI and phylogenetic studies and the distinct pathogenicity profiles and arthropod vectors used by different Borrelia spp for their transmission we are proposing a division of the genus Borrelia into two separate genera an emended genus Borrelia containing the causative agents of relapsing fever and a novel genus Borreliella gen nov containing the causative agents of Lyme disease

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