title: ospC diversity in Borrelia burgdorferi: different hosts are different niches.
abstract: The outer surface protein C (ospC) locus of the Lyme disease bacterium, Borrelia burgdorferi, is at least an order of magnitude more variable than other genes in the species. This variation is classified into 22 ospC major groups, 15 of which are found in the northeastern United States. The frequency distributions of ospC within populations suggest that this locus is under balancing selection. In multiple-niche polymorphism, a type of balancing selection, diversity within a population can be maintained when the environment is heterogeneous and no one genotype has the highest fitness in all environments. Genetically different individuals within vertebrate species and different vertebrate species constitute diverse environments for B. burgdorferi. We examined four important host species of B. burgdorferi and found that the strains that infected each species had different sets of ospC major groups. We found no variation among conspecific hosts in the ospC major groups of their infecting strains. These results suggest multiple niches create balancing selection at the ospC locus.
authors.affiliation: Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York 11794-5245, USA. brisson@life.bio.sunysb.edu
authors.forename: Dustin
authors.initials: D
authors.lastname: Brisson
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Dykhuizen
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D025065:Borrelia burgdorferi / Q000235:genetics* / Q000472:pathogenicity; D005787:Gene Frequency; D014644:Genetic Variation; D006790:Host-Parasite Interactions / Q000235:genetics*; D008074:Lipoproteins / Q000235:genetics; D008193:Lyme Disease / Q000635:transmission*; D010542:Peromyscus / Q000469:parasitology; D012589:Sciuridae / Q000469:parasitology; D012641:Selection, Genetic; D012788:Shrews / Q000469:parasitology
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D008074:Lipoproteins; C079616:OspC protein