The low sequence identity between Por and PorB, the low levels of genetic exchange, as indicated by the FST results, together with the relatively weak positive selection pressures acting on the N. lactamica porin and the lack of immunological cross-reactivity with meningococcal PorB (Finney et al., 2007; Kim et al., 1989), suggest that this protein may not be important in the induction of any cross-protective immune responses that might protect against meningococcal disease. This evidence concerns the gene POR and meningococcal infection.