Genetic details, optimization and phage life histories.

Optimality models assume that phenotypes evolve by natural selection largely independently of underlying genetic mechanisms. This neglect of genetic mechanisms is considered an advantage by some evolutionary biologists but a fatal flaw by others. The controversy has gone unresolved, in part, from a lack of complex phenotypes that meet optimality criteria and for which the underlying genetic mechanisms are known. Here, we look at both perspectives for lysis time in bacteriophages. We find that the basic assumptions of the optimality model are compatible with the genetic details, but the optimality model is limited in its ability to accommodate lysis time plasticity because the mechanistic underpinnings of plasticity are poorly known.