http://humanistheritage.org.uk/articles/john-maynard-smith/ > > Recommended. Without going into the actual chemical structure > of proteins and bases he explains how the biological code works > and also puts forward a theory about how it could have evolved.-The following article discusses the comet theory of the origin of lilfe and how glycine, the simplest amino acid might have arrived. Note that it does not support the RNA-world approach:- http://arstechnica.com/science/news/2010/09/comet-impact-shockwave-may-have-planted-see...