Wagner plans to investigate this hypothesis in the context of the yeast Saccharomyces cerevisiae. An important fact about RNA folding is that many sequences do not change their shape when certain positions are mutated. An evolving population can drift on such a neutral network until a more advantageous shape comes within mutational reach. This enables evolutionary change to occur that otherwise would have been impossible. In this way neutrality is seen to be both a buffer against change and an enabler of change.
Thermal fluctuations cause a molecule to equilibrate among alternative low-energy shapes.
References Cadigan K.M., U. Grossniklaus, and W. J. Gehring. Dun, R.B. and A.S. Fraser. Dykhuizen et al. Selective neutrality of 6pgd allozymes in escherichia-coli and the effects of genetic background. Fell, D. Understanding the control of metabolism .