Fig 1. Overview of the proteins assigned to the four age groups: (a) the fraction of proteins belonging to each age group, (b) the average length, in amino acids, (c) the average GC content of the genes, (d) intrinsic disorder predicted by IUpred (long), (e) percentage of transmembrane residues, (f) percentage of residues in low-complexity regions, percentage of residues predicted to be in (g) a coil, (h) a β-sheet and (i) in a helix.

The difference between orphans and ancient is statistically significant for all the considered properties: the p-value of a rank-sum test is always <10⁻¹⁴¹.