Evolution of duplicated genes

Gene duplication has been recognized as a major process in the evolution of new protein functions. I study the evolution of duplicated genes to shed light on what happens after a promiscuous gene with two traits has been duplicated. Will the two copies stay multifunctional; specialize for the same function or subfunctionalize for different functions? For this purpose, I am using laboratory evolution experiments in E. coli, where the conditions can be well controlled and different scenarios can be tested. Specifically, the E. coli cells will carry a plasmid containing a duplicated promiscuous gene coding for a dual-color-emitting fluorescent protein (coGFP). By applying tools from synthetic biology, I can control and vary gene copy numbers, selection pressures, mutation rates and the expression levels. The outcomes of the different experiments can be compared to each other and to theoretical predictions to improve our understanding of how duplicated genes evolve.