Figure 3

Hybridizations of S. enterica serovar Typhimurium and S. bongori, each to a serovar Typhimurium reference on a Typhimurium LT2 array. (a) Distribution of log ratios for serovar Typhimurium and S. bongori. Serovar Typhimurium is expected to hybridize to all spots, whereas S. bongori is expected to have divergent genes. Note the left tail in the S. bongori distribution, which is absent in the serovar Typhimurium distribution (skewness = 0.322 for Typhimurium; skewness = -2.094 for Bongori). (b) Magnification of the region between -2.0 and 0.5. The circles represent the transition regions, where the main peak meets the left tail for each distribution. The arrow represents the constant cutoff which previous publications have used to distinguish present and divergent genes.