About the interrelation of evolutionary rate and protein age.

Evolutionary rate and gene age are interrelated when the age of a gene is assessed by the taxonomic distribution in the gene family. This is because homology detection by sequence comparison is depending on sequence similarity. We estimate family specific rates of protein evolution for orthologous families with representatives from man, fugu, fly, and worm. In fact, we observe that younger proteins tend to evolve faster than older ones. We estimate time points of duplication events that gave rise to novel protein functions and show that younger proteins were duplicated more recently than older ones.