Amino acid usage changes based on GC content of synonymous codons in ocean communities. (a,b) Charts include only those amino acids whose frequency significantly increased (blue) or decreased (red) in the RNA relative to the corresponding DNA reads (a) or in the expressed genes relative to the non-expressed genes in the DNA reads only (b). Significant increases/decreases are categorized based on the GC content (x-axis) of the amino acid, where GC content = (Number of GC bases among synonymous codons)/(Number of total bases among synonymous codons). Data from all 11 DNA/RNA ocean samples are pooled; these charts exclude the soil data, in which GC enrichment in the RNA was not observed.
Stewart et al. Genome Biology 2011 12:R26 doi:10.1186/gb-2011-12-3-r26