Fig. 6. Clusters of Orthologous Groups (COG) functional categories that showed no correlation with genome size. These categories showed no correlation with genome size (at a P value threshold of 0.01) for one or both of the sets of species tested (i.e., all solid squares and solid squares with > 2,000 ORFs). Only datapoints representing bacterial genomes are shown, because Archaea had significantly different genomic fractions in many of the categories shown.