title: Population subdivision and the detection of recombination in non-typable Haemophilus influenzae.
abstract: The disparity in diversity between unencapsulated (non-typable; NT) and encapsulated, serotypable Haemophilus influenzae (Hi) has been recognized for some time. It has previously been suggested that the wider diversity evidenced within NTHi compared with typable lineages may be due to different rates of recombination within the encapsulated and NT populations. To examine whether there is evidence for different levels of recombination within typable and NT lineages of Hi, we performed a statistical genetic analysis of 819 distinct genotypes of Hi to explore the congruence of serotype with population genetic clustering, and to identify patterns of recombination within the Hi population. We find that a significantly larger proportion of NT isolates show evidence of recombination, compared with typable isolates, and also that when admixture is present, the total amount of recombination per strain is greater within NT isolates, compared with the typable population. Furthermore, we demonstrate significant heterogeneity in the number of admixed individuals between NT lineages themselves, while such variation was not observed in typable lineages. This variability suggests that factors other than the presence of capsule are important determinants of recombination rate in the Hi population.
authors.affiliation: Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London W2 1PG, UK.|Pathogen Genomics, Wellcome Trust Sanger Institute, Cambridge CB22 5EZ, UK.
authors.forename: Thomas Richard
authors.initials: TR
authors.lastname: Connor
authors.affiliation: Department of Mathematics and Statistics, PO Box 68, University of Helsinki, 00014, Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Corander
authors.affiliation: Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.|Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London W2 1PG, UK.
authors.forename: William Paul
authors.initials: WP
authors.lastname: Hanage
mesh_terms: D016000:Cluster Analysis; D014644:Genetic Variation; D005838:Genotype; D006193:Haemophilus influenzae / Q000145:classification* / Q000235:genetics*; D058885:Multilocus Sequence Typing; D011995:Recombination, Genetic; D012703:Serotyping