Protein length distribution by age and origin. The box plots summarize the distribution of sequence lengths (in amino acids) of the proteins with interactions found in each age/origin group. Young proteins are shorter than older proteins, and young novel proteins are significantly shorter than all other groups, including young proteins created by duplication.
Capra et al. Genome Biology 2010 11:R127 doi:10.1186/gb-2010-11-12-r127