Figure 5From: Comparative genomics of prevaccination and modern Bordetella pertussis strainsTemporal trend in the frequency of a SNP located in the promoter region for the type III secretion system. The SNP involved an A/G transition and was located between the type III secretion toxin gene bteA and its chaperone btcA. The two genes are oriented back to back. The period 1949-2008 was investigated using 44 strains.Back to article page