Fig 3.

Genomic signature for endosporulation. (A) The signature is defined as those genes present in 90% of endosporulating bacteria and in no more than 5% (inner circle) or 10% (outer circle) of the remaining bacterial species. Note that the first gene of the spoIIIA operon is only found at the 10% cutoff. Genes with an established function in sporulation, genes coding for the RNA polymerase σ factors that control gene expression during sporulation and genes encoding global transcriptional regulators are shown, as is one gene, tepA, with a predicted function in protein secretion but which has not yet been implicated in sporulation. Also shown are genes with no assigned function. The positions of the genes are shown in degrees in the B. subtilis 168 chromosome. (B) Percentage of the minimal core in genomes, showing that endosporulating organisms all have a high proportion of this signature, and that all mycobacteria and exosporulating organisms have less than 20% of this signature. Those organisms not known to sporulate but that show a proportion of the signature comparable to the known endosporulators are predicted to be able to form endospores.