Distribution of genes on the basis of purine content at (a) nonsynonymous codon positions (R1+2); (b) synonymous codon positions (R3S) for seven mesophiles (Green line), seven hyperthermophiles (Red line), and N. equitans (Pink line). (c) Relationship between optimal growth temperature (OGT) and average Purine-pyrimidine ratio (RY ratio) of protein coding sequences. (d) Relationship between optimal growth temperature (OGT) and average GC-content of structural RNA sequences. The green, red and pink colors represent mesophiles, hyperthermophiles and N. equitans respectively. The filled circles for tRNAs and the filled triangles for rRNAs.
Das et al. BMC Genomics 2006 7:186 doi:10.1186/1471-2164-7-186