My broad objective is to understand how recombination impacts upon the biology of Neisseria gonorrhoeae with special emphasis towards elucidating the molecular mechanism underlying pilin antigenic variation. The neisseria as a genus show a remarkable propensity for undergoing homologous recombination both within a species and between closely related members of the genus. Such promiscuity allows the dissemination of chromosomal genetic elements throughout a population within nature, leading to a large repertoire of variant subtypes. Consequently, the presence of large variant populations makes therapeutic intervention more difficult and impairs the efficacy of many vaccine candidates.