““The third cardinal feature of gene regulation, Monod and Jacob discovered, was that every gene had specific regulatory DNA sequences appended to it that acted like recognition tags. Once a sugar sensing-protein had detected sugar in the environment, it would recognize one such tag and turn the target genes on or off. That was a gene's signal to make more RNA messages and thereby generate the relevant enzyme to digest the sugar. A gene, in short, possessed not just information to encode a protein, but also information about when and where to make that protein. All that data was encrypted in DNA, typically appended to the front of every gene (although regulatory sequences) an also be appended to the ends and middle of genes). The combination of regulatory sequences and the protein-encoding sequence defined a gene.””
