Podeu consultar el llibre complet a: http://hdl.handle.net/2445/46988

Although several approaches have been attempted, the estimation of recombination frequencies in natural populations of bacteria remains challenging. Previous studies have demonstrated a wide variety of situations among bacterial species, ranging from the clonal diversification of Salmonella or Escherichia coli, which are mainly due to mutation, to the frequent recombination found in Neisseria gonorrhoeae or Helicobacter pylori. Most of the population studies done with bacterial species suggest that recombination occurs in nature but that it is infrequent compared to mutation. Consequently, bacterial populations consist largely of independent clonal lineages. Our research suggests little or null influence of recombination in the genetic structure of "Aeromonas hydrophila Species Complex", despite the presence of some strains with recombinant gene fragments.