The Number of ORFs in Each Genome vs. Genome Size for the Three Extant Domains of Life on Earth.

<p>The points are data from 1128 genomes available on the GOLD database <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036624#pone.0036624-The1" target="_blank">[3]</a> in early 2010. In this log-log plot, the <i>x</i>-axis represents the genome size (<i>G</i>) in kilobasepairs. For each genome we plot on the <i>y</i>-axis the number of ORFs quoted for the genome in the above database. In order to facilitate comparisons, we have drawn a red diagonal line on a vertical/horizontal scale where 1 vertical axis unit corresponds to 1 kbp on the horizontal axis. The Prokaryotic genomes cluster around this (slope = 1) line. The fit to the Prokaryotes given by Eqn. (6) is represented here as a cyan line. The dashed line represents the best fit to the Eukaryotic ORFs and corresponds to a Benford distribution, Eqn. (11), if we neglect the statistically insignificant contribution from the combination of the first two terms, . Note the wide range of genome sizes that the fit accommodates. See the Discussion Section regarding the right-hand axis.