Emergence in molecular biology

A key framework for molecular biophysics is that structure determines property which in turn determines function. But `function’ is not a reducible concept (something Michael Polanyi emphasized).
John Hopfield is a Professor of Molecular Biology at Princeton University and also was recently President of the American Physical Society. In a helpful piece in Nature about physicists working in molecular biology Hopfield states, ``The word `function’ does not exist in physics, but physicists need to learn about it, otherwise they will be in a sandbox playing by themselves.’’

In molecular biology, a dramatic, puzzling, and fascinating manifestation of emergence is how differences in a string of letters (the nucleotides A,G,T, and C) encoded at the molecular level in DNA lead to different cell types, different acquired characteristics, and even different species.