Figure 5

Determination of thresholds for absent and conserved genes. We calculated the proportion of genes belonging to each of four PTI categories at 0.2 LR intervals in order to determine LR thresholds that could be used to predict absent and conserved genes with a high degree of certainty. Below a LR of -3.0, the false positive rate for conserved genes is less than 1%; similarly, the false positive rate for absent genes above LRs of -0.8 is also less than 1%. In the LR interval between -3.0 and -0.8, particularly approaching the -0.8 boundary, there are significant number of genes from more than one PTI category and thus there is significant risk of misclassification.