title: Comparative genomics reveals multiple pathways to mutualism for tick-borne pathogens.
abstract: Multiple important human and livestock pathogens employ ticks as their primary host vectors. It is not currently known whether this means of infecting a host arose once or many times during evolution.
  
  
  
  In order to address this question, we conducted a comparative genomics analysis on a set of bacterial pathogens from seven genera - Borrelia, Rickettsia, Anaplasma, Ehrlichia, Francisella, Coxiella, and Bartonella, including species from three different host vectors - ticks, lice, and fleas. The final set of 102 genomes used in the study encoded a total of 120,046 protein sequences. We found that no genes or metabolic pathways were present in all tick-borne bacteria. However, we found some genes and pathways were present in subsets of tick-transmitted organisms while absent from bacteria transmitted by lice or fleas.
  
  
  
  Our analysis suggests that the ability of pathogens to be transmitted by ticks arose multiple times over the course of evolution. To our knowledge, this is the most comprehensive study of tick transmissibility to date.
authors.affiliation: School of Electrical Engineering and Computer Science, Washington State University, P.O. Box 642752, Pullman, USA.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Lockwood
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, P.O. Box 647040, Pullman, 99164-7040, USA.|Paul G. Allen School for Global Animal Health, Washington State University, PO Box 647090, Pullman, 99164-7090, USA.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Brayton
authors.affiliation: School of Electrical Engineering and Computer Science, Washington State University, P.O. Box 642752, Pullman, USA. shira@eecs.wsu.edu.|Department of Veterinary Microbiology and Pathology, Washington State University, P.O. Box 647040, Pullman, 99164-7040, USA. shira@eecs.wsu.edu.|Paul G. Allen School for Global Animal Health, Washington State University, PO Box 647090, Pullman, 99164-7090, USA. shira@eecs.wsu.edu.
authors.forename: Shira L
authors.initials: SL
authors.lastname: Broschat
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D016000:Cluster Analysis; D019295:Computational Biology / Q000379:methods; D006801:Humans; D053858:Metabolic Networks and Pathways; D054892:Metagenome; D056186:Metagenomics / Q000379:methods; D008003:Phthiraptera / Q000382:microbiology; D010802:Phylogeny; D005423:Siphonaptera / Q000382:microbiology; D017282:Tick-Borne Diseases / Q000382:microbiology* / Q000635:transmission
keywords: Comparative genomics; Phylogenomic network; Tick-borne pathogens