Figure 1
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.