Figure 1.

Percent GC-content versus length of intergenic regions (IGRs) in 'Cand. P. ubique'. Transfer and ribosomal RNAs are as annotated by Rfam [24] and RefSeq (RefSeq accession NC_007205.1). Other structured RNAs include known riboswitches, 4.5S RNA (SRP RNA), RNase P RNA and tmRNA.