“…It would also account for an inherent mechanism of self-recognition, which would facilitate preferential, but not exclusive, DNA exchange within a Genus species. The pan-genome of S. enterica subspecies 1 has a mosaic structure between serotypes, with frequent inversions, deletions, and insertions occurring between serotypes; however, the chromosomal arrangement of many Salmonella lineages is comparatively stable [25,32,38,39]. AT 8+mers being important to the processes of DNA replication, repair and acquisition by repair mechanisms and homologous recombination would account for i) the stability of some serotypes with conserved genome features that are persistent, e. g. serovar Typhimurium [1], ii) the occasional emergence of a new serotype that happens to undergo clonal expansion in an environment favorable for growth, e. g. serovar Tennessee in peanut butter [40,41], iii) the rare emergence of a hybrid strain following a major recombination event that results in rapid proliferation of a serotype with new biological properties, e. g. serovar Enteritidis and its ability to contaminate and survive in the internal contents of eggs [42], and iv) the periodic emergence and disappearance of serotypes that are not optimized for the survival in the environment in which they are generated.…”