By showing the implausibility of the co-option model of protein evolution and the need for multiple coordinated mutations in order to generate multisite features in proteins, Axe and Gauger confirmed that genes and proteins themselves represent complex adaptations—entities that depend upon the coordinated interaction of multiple subunits that must arise as a group to confer any functional advantage. The need for coordinated mutations means that evolutionary biologists cannot just assume that mutations will readily generate new genes and traits, as neo-Darwinists have long presupposed.
