Is the Genetic Code Well-Designed?

[swamidass (S. Joshua Swamidass)]

I think the “perfection” of the genetic code is a myth, and so is the argument that it’s perfection is a convincing argument for design. Likewise, I find the “bad design” arguments to be unconvincing too. They assume we know the design goals, and also imply that if they system evolved it was not designed. Maybe God designed with evolution, right?

@vjtorley

I submit that if the standard genetic code were situated on a local peak, it would at least be a choiceworthy code for a designer to produce. But when it’s halfway from an average random code to the summit of the local peak, I have to ask myself: why would a designer pick a code like that?

My counter argument is three fold.

1. Maybe the code is optimizing a different design goal. Perhaps error tolerance is important, but other things are too. We cannot know Perhaps we do not want too much error tolerance, because we want some errors, so things can evolve. In this case, evolution itself might be the design goal, which might benefit from a trade off between error and accuracy.

2. Perhaps what we see is not so important to optimize regardless, and just records the history of what happened here, and perhaps the path required to arrive at a genetic code. It could be a “frozen accident”, though the more neutral terminology would be a random dice. Or it could be…#3.

3. This might even be the only viable (or vastly most likely) code possible given the constraints of chemistry if we require a stepwise path to get from a simplified code to a complex one. In this case, it would not even be properly called a code (!). Several constraints (which we cannot even know for sure) might be it has to be able to encode useful proteins with a limited (and easy to find) set of amino and nucleic acids. Perhaps there is only a very small number of codes capable of doing this, which constrains the starting point dramatically. Then, we can add a few aa at a time and so on.

I’m not sure which of these is correct, but who could know this anyways? There are just too many unknowns. We know that the genetic code works well enough, but neither “good design” nor “bad design” appears to be clear from the evidence. In context, @vjtorley is disputing the mythology of “perfection in the Genetic Code is evidence it was designed de novo, without an incremental process”; so I do ultimately agree with @vjtorley’s argument, but I would resist taking it too far.