Figure 2
From: Homopolymeric tracts represent a general regulatory mechanism in prokaryotes
Histograms showing the frequency of HTs in 20 windows each representing 5% of the length of the coding genes. (i.e., the first bar represents the frequency of HTs in the first 5% of the coding genes) for (A) all 81 bacterial genomes and (B) all 18 archaeal genomes. The data shown represent the frequencies among all bacterial or archaeal genomes (i.e., data for all genomes were pooled and not analyzed separately for each organism). Statistical analyses indicate that longer poly(A) and poly(T) HTs are located significantly closer to the 5'end of coding genes relative to shorter tracts (P-values from one-sided Wilcoxon tests are shown above graphs, e.g., P < 1 × 10-4 indicates that A6 tracts are located significantly closer to at the 5' ends of genes as compared to A5 tracts [for bacterial genomes]); AAA and TTT codons were also located significantly (P < 1 × 10-15) closer to the 5' as compared to AAG and TTC, respectively.