One way of developing these ideas is to focus on the evolved functions of the genetic machinery as a whole (Godfrey-Smith 1999). Carl Bergstrom and Martin Rosvall take this approach, emphasising the adapted, impressively engineered features of intergenerational gene flow in developing their “transmission sense of information”. Bergstron and Rosvall point out that intergeneration gene flow is structured so as to make possible the transmission of arbitrary sequences (so the message is relatively unconstrained by the medium); that information is stored compactly and stably; that the bandwidth is large and indefinitely extendable. DNA sequences are reliably replicable with very high fidelity, so transmission is accurate, yet the mapping between DNA and amino acid sequence seems optimised to reduce the impact of those errors that do occur. Many point mutations are mapped onto the same or a chemically similar amino acid. Bergstrom and Rosvall conclude both that DNA replication is an exquisitely designed information channel, and that we can tell this from the characteristics of the DNA-amino acid system itself. We do not need to know what signals from the parental generation say to the offspring generation, in order to know that the characteristics of DNA replication are explained by its information-carrying capacities (Bergstrom and Rosvall 2011).