Schematic representation of the age classification of proteins. We classify the yeast proteins into 5 age classes based on the phylogenetic relationship of 138 species . Inner nodes on the evolutionary tree represent ancestral organisms and inner nodes on the path from root to S. cerevisiae indicate representative time points when the yeast proteins originated during evolution. The path that leads to S. cerevisiae is highlighted in bold and 5 age classes are labeled with different colors. The inset table shows the age class distribution of the yeast proteins in the PIN of DIP_YEAST_CORE. The inner nodes on the path from root to H. sapiens are also labeled. For the age classification of human proteins, please refer to Supplementary Methods and Results.
Liu et al. BMC Evolutionary Biology 2011 11:133 doi:10.1186/1471-2148-11-133