title: Mitochondrial DNA sequence variation in ixodes pacificus (Acari: ixodidae).
abstract: The western black-legged tick, Ixodes pacificus, is a primary vector of the spirochaete, Borrelia burgdorferi, that causes Lyme disease. We used variation in a 355-bp DNA portion of the mitochondrial cytochrome oxidase III gene to assess the population structure of the tick across its range from British Columbia to southern California and east to Utah. Ixodes pacificus showed considerable haplotype diversity despite low nucleotide diversity. Maximum parsimony and isolation-by-distance analyses revealed little genetic structure except between a geographically isolated Utah locality and all other localities. Loss of mtDNA polymorphism in Utah ticks is consistent with a post-Pleistocene founder event. The pattern of genetic differentiation in the continuous part of the range of Ixodes pacificus reinforces recent recognition of the difficulties involved in using genetic frequency data to infer gene flow and migration.
authors.affiliation: Department of Environmental Science, Division of Insect Biology, University of California at Berkeley, Berkeley, CA 94720, USA. dkain@agnesscott.edu
authors.forename: D E
authors.initials: DE
authors.lastname: Kain
authors.forename: F A
authors.initials: FA
authors.lastname: Sperling
authors.forename: H V
authors.initials: HV
authors.lastname: Daly
authors.forename: R S
authors.initials: RS
authors.lastname: Lane
mesh_terms: D000818:Animals; D002170:Canada; D004272:DNA, Mitochondrial / Q000032:analysis / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000032:analysis / Q000235:genetics; D014644:Genetic Variation; D006239:Haplotypes / Q000235:genetics; D018884:Ixodes / Q000235:genetics*; D010802:Phylogeny; D014481:United States
chemical_list: D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV