Fig. 30. Comparison of average amino acid compositions of proteins obtained from M. tuberculosis genome data (average GC content = 65.6%) (A), and E. coli genome data (average GC content = 50.8%) (B), with those of hypothetical proteins encoded by simulated genes (average GC contents = 65.6% (A); and 50.5% (B)) derived from the GC-rich ancestral gene, as given in Fig. 29.