Crick's operational definition of genetic information was "the determination of a sequence of units" either in a nucleic acid (DNA or RNA) or in the amino acid chain of a protein. A separate part of Crick's argument was the sequence hypothesis - the idea that the three dimensional structure of protein is in some way inherent in the sequence and emerges s the amino acid chain is assembled. He hypothesized that there is no separate genetic code for protein conformation. By comparing a novel DNA sequence with known amino acid sequences and three-dimensional protein structures, it is possible to make predications about the three-dimensional conformation of the protein that could be produced by the DNA. However, despite our deep understanding of the physicochemical rules underlying the shape that proteins take, there is as yet no way of predicting with absolute certainty the three-dimensional structure of a protein from a DNA sequence.