Fig. 3: A metabolic scaling law emerges as plasmids approach chromosome length scales.
Comparison of scaling between chromosomes and plasmids on a log-log plot. Plasmids are shown in blue, megaplasmids (plasmids > 500,000 bp in length) are shown in red, and chromosomes are shown in green. The linear regression between log10(metabolic genes) and log10(length) for chromosomes is shown in black. The gray line indicates the average length of plasmids containing n metabolic genes, where n is an arbitrary integer. As n increases, the scaling between plasmid length and the number of metabolic genes n (shown in gray) approaches the scaling for chromosome length and number of metabolic genes n (shown in black). Source data are provided as a Source Data file. A Plasmids can vary in size by orders of magnitude but still carry similar numbers of metabolic genes—but as plasmids reach megaplasmid scales (>500,000 bp in length), their metabolic gene content begins to scale like chromosomes. B The emergent metabolic scaling law holds for microbes sampled across diverse environments. The ecological provenance of each replicon was annotated per the method described in Maddamsetti et al.3 (Methods).
