| Institution: | 1. Department of Zoology, University of Oxford, , Oxford, OX1 3PS UK;2. Institute of Life Science, College of Medicine, Swansea University, , Swansea, SA2 8PP UK;3. Department of Mathematics and Statistics, University of Helsinki, , FI‐00014 Helsinki, Finland;4. Department of Food Hygiene and Environmental Health, University of Helsinki, , FI‐00014 Helsinki, Finland;5. Department of Information and Computer Science, Helsinki Institute for Information Technology HIIT, Aalto University, , FI‐00076 Aalto, Finland;6. Department of Bacteriology and Food Safety, Animal Health and Veterinary Laboratories Agency (AHVLA), , New Haw, Addlestone, Surrey, KT15 3NB UK;7. Cardiff School of Biosciences, Cardiff University, , Cardiff, CF10 3AT UK;8. School of Medicine and Dentistry, University of Aberdeen, , Foresterhill, Aberdeen, AB25 2ZD UK;9. School of Biological Sciences, University of Aberdeen, , Foresterhill, Aberdeen, AB25 2ZD UK;10. Wellcome Trust Sanger Institute, , Hinxton, Cambridge, CB10 1SA UK;11. Department of Epidemiology, Harvard School of Public Health, , Boston, MA, 02115 USA |
| Abstract: | Homologous recombination between bacterial strains is theoretically capable of preventing the separation of daughter clusters, and producing cohesive clouds of genotypes in sequence space. However, numerous barriers to recombination are known. Barriers may be essential such as adaptive incompatibility, or ecological, which is associated with the opportunities for recombination in the natural habitat. Campylobacter jejuni is a gut colonizer of numerous animal species and a major human enteric pathogen. We demonstrate that the two major generalist lineages of C. jejuni do not show evidence of recombination with each other in nature, despite having a high degree of host niche overlap and recombining extensively with specialist lineages. However, transformation experiments show that the generalist lineages readily recombine with one another in vitro. This suggests ecological rather than essential barriers to recombination, caused by a cryptic niche structure within the hosts. |
