The concept of developmental reprogramming and the quest for an inclusive theory of evolutionary mechanisms.

Evolutionary developmental biology has already made a major contribution to our understanding of evolutionary patterns, notably homology. However, while it has the potential to make an equally important contribution to our understanding of evolutionary mechanisms, and indeed to the integration of mechanism and pattern, it has not yet done so. This paper explores how this potential may be realized. In particular, I focus on the limitations of present-day neo-Darwinian theory, and indicate how a combination of the neo-Darwinian and "evo-devo" approaches provides a more inclusive view of evolutionary mechanisms with greater explanatory power. There is a particular focus on developmental reprogramming, which lies logically between mutation and selection, yet has been neglected in mainstream evolutionary theory. The inclusion of developmental reprogramming in the list of evolutionary mechanisms leads to a view that the direction of evolutionary change is determined by a combination of internal and external factors, rather than being controlled entirely by the environment.