A Retrospective Study on Genetic Heterogeneity within Treponema Strains: Subpopulations Are Genetically Distinct in a Limited Number of Positions

Background: pathogenic uncultivable treponemes comprise human and animal pathogens including agents of syphilis,yaws,bejel,pinta,and venereal spirochetosis in rabbits and hares. a set of 10 treponemal genome sequences including those of 4 treponema pallidum ssp. pallidum (tpa) strains (nichols,dal-1,mexico a,ss14),4 t. p. ssp. pertenue (tpe) strains (cdc-2,gauthier,samoa d,fribourg-blanc),1 t. p. ssp. endemicum (ten) strain (bosnia a) and one strain (cuniculi a) of treponema paraluisleporidarum ecovar cuniculus (tplc) were examined with respect to the presence of nucleotide intrastrain heterogeneous sites. methodology/principal findings: the number of identified intrastrain heterogeneous sites in individual genomes ranged between 0 and 7. altogether,23 intrastrain heterogeneous sites (in 17 genes) were found in 5 out of 10 investigated treponemal genomes including tpa strains nichols (n = 5),dal-1 (n = 4),and ss14 (n = 7),tpe strain samoa d (n = 1),and ten strain bosnia a (n = 5). although only one heterogeneous site was identified among 4 tested tpe strains,16 such sites were identified among 4 tpa strains. heterogeneous sites were mostly strain-specific and were identified in four tpr genes (tprc,gi,i,k),in genes involved in bacterial motility and chemotaxis (flii,chec-fliy),in genes involved in cell structure (murc),translation (prfa),general and dna metabolism (putative sam dependent methyltransferase,topa),and in seven hypothetical genes. conclusions/significance: heterogeneous sites likely represent both the selection of adaptive changes during infection of the host as well as an ongoing diversifying evolutionary process. © 2015 čejková et al.