In “Arrival of the Fittest” Wagner goes to great lengths to take the reader, in a much better way than I can reproduce here, through his ideas about how nature is set up to supercharge evolution. The authors premise is that of a ‘Universal Library’ where every conceivable combination of something can exist. In such a library a single item, be it a DNA code, the sequence of amino acids in a protein or a metabolic pathway, is connected via single changes (in any one of its parts) to other items in the library. Some, in fact probably many of these versions in the library, are useless/defunct in the sense that they would not work in the real world and so any organism that possess them would not survive. However, many of these versions are perfectly viable and so an organism would be able to survive if it had that copy.
Using large computer models in these libraries it is possible to move through them by making single changes that do not disrupt the function of the thing you are interested in (be it DNA, protein or metabolism). Following the logic laid down as you go through the book it becomes clear that there are clear pathways through DNA to protein to metabolic pathways. There are even multiple pathways from any one point in the library to any other point (that still gives the same end result) but when the start and end points are compared on their nucleotide/amino acid/enzyme combination level they are completely different. In effect there are many ways to solve the same problem and they are connected in many ways via simple, singular step changes.
Not only can the same processes easily be conserved with this logic but new processes are easily made, as these Universal Libraries contain every conceivable combination. Wagner shows that new metabolic pathways can easily be made, allowing for the exploitation of new food stuffs, without loss of function occurring. The amazing thing is that there are huge numbers of these pathways that criss-cross these libraries.
These theories show that life processes are robust and that it creates genotype networks which, in Wagner’s words “enable innovation, the very kind that allow life to cope with environmental change, increase its complexity, and so on, in an ascending spiral of ever-increasing innovability.”.
I have probably done a very bad job of trying to convey the ideas in this book, but hopefully I have peaked your interest enough to go out an read it, which I definitely recommend (there is a reason that Wagner has been paid to write a book and I haven’t!).
This book has genuinely made me look at evolution from a novel perspective, and these revolutionary ideas show how the power of modern computing can be incorporated into evolutionary biology with breath-taking results.