Facilitated variation: a new paradigm emerges in biology

Facilitated variation is the first comprehensive theory of how life works at the molecular level, published in 2005 by systems biologists Marc Kirschner and John Gerhart in their book The Plausibility of Life: Resolving Darwin’s Dilemma. It is a very powerful theory, is supported by a great deal of evidence, and the authors have made it easy to understand. It identifies two basic components of heredity: (a) conserved core processes of cellular structure, function and body plan organization; and (b) modular regulatory mechanisms that are built in special ways that allow them to be easily rearranged (like ®Lego blocks) into new combinations to generate variable offspring. Evolvability is thus built-in, and the pre-existing molecular machinery facilitates the incorporation of new DNA sequence changes that occur via recombinations and mutations. The question of origin becomes especially acute under this new theory because the conserved core processes and the modular regulatory mechanisms have to already be in place before any evolution can occur. The new molecular evidence shows virtually all the main components of neo-Darwinian theory are wrong...