Gene duplication is one of the major ways of evolving genes with novel functions. There are two models on how gene duplications lead to new functions: 1) The NEO-F Model (Neo-functionalization) & 2) EAC (Escape of Adaptive Conflict) Model. In NEO-F model, new function is achieved after the event of duplication. On the contrary, in relatively unexplored EAC model genes acquire novel function which maintains its ancestral function also. This gene is constrained from improving either novel or ancestral function because of detrimental pleiotropic effects on the other function. But upon duplication, any of the copies can be selected for enhancement of the novel function. In a recent paper accepted in Nature Marias et al. explores the evolution of Anthocyanin pathway gene dihydroflavonol-4-reductases (DFR, EC number 1.1.1.219) in Eudicots with respect to both of these models. Their study suggests EAC as mode of evolutionary change of this gene. Besides they also conclude EAC may be far common mode of evolution than previously thought. One interesting conclusion of their study is that the evolution of novel function may sometimes be a byproduct of the evolution in enhanced ancestral activity.
Ref: Marais et al (2008). Escape from adaptive conflict after duplication in an anthocyanin pathway gene. doi:10.1038/nature07092.
