Continuing the discussion from Swapping Iron For Magnesium in the Ribosome:
An interesting question about this comes to mind. We know that the genetic code can evolve in living systems, so why don’t see see more than one cluster? I wonder if there are two things opposing drift too far from the universal code.
- The larger a genome gets, the harder it is to evolve the code, because it becomes harder impossible to adapt codons quickly enough.
- There are costs to becoming incompatible with the universal code, as now horizontal gene transfer will no longer be viable, except with compatible organisms.
- Larger more complex organisms are subject to 1. Bacteria are more subject to 2.
With that in mind, viruses are an interesting case. Changing the code could confer resistance to viruses. Viruses themselves seem constrained of the code of their host.
Archea is another interesting case. It is a different domain of life, but has the same code as bacteria, perhaps the compatibility is selected for because it enables horizontal gene transfer?
@Art, @mercer, @cwhenderson, @glipsnort (and the other biologists) has anyone thought about this? I wonder how we could test it…or if someone else did already. Is there a way to test for the selective positives and negatives of having an altered genetic code in different contexts?