The DNA Code and Evolution
The DNA code is used in cells to translate a sequence of nucleotides into a sequence of amino acids, which then make up a protein. In the past fifty years we have learned four important things about the code:
1. The DNA code is universal. There are minor variations scattered about, but the same canonical code is found across the species.
2. The DNA code is special. The DNA is not just some random, off the shelf, code. It has unique properties, for example that make the translation process more robust to mutations. The code has been called “one in a million,” but it probably is even more special than that. For instance, one study found that the code optimizes “a combination of several different functions simultaneously.”
3. Some of the special properties of the DNA code only rarely confer benefit. Many of the code’s special properties deal with rare mutation events. If such properties could arise via random mutation in an individual organism, their benefit would not be common.
4. The DNA code’s fitness landscape has dependencies on the DNA coding sequences and so favors stasis. Changes in the DNA code may well wreak havoc as the DNA coding sequences are suddenly not interpreted correctly. So the fitness landscape, at any given location in the code design space, is not only rugged but often is a local minimum, thus freezing evolution at that code.
Observation #1 above, according to evolutionary theory, means that the code is the ultimate homology and must have been present in the last universal common ancestor (LUCA). There was essentially zero evolution of the code allowed over the course of billions of years.
This code stasis can be understood, from an evolutionary perspective, using Observation #4. Given the many dependencies on the DNA coding sequences, the code can be understood to be at a local minimum and so impossible to evolve.
Hence Francis Crick’s characterization, and subsequent promotion by later evolutionists, of the code as a “frozen accident.” Somehow the code arose, but was then strongly maintained and unevolvable.
But then there is Observation #2.
The code has been found not to be mundane, but special. This falsified the “frozen accident” characterization, as the code is clearly not an accident. It also caused a monumental problem. While evolutionists could understand Observation #1, the universality of the code, as a consequence of the code being at a fitness local minimum, Observation #2 tells us that the code would not have just luckily been constructed at its present design.
If evolution somehow created a code to begin with, it would be at some random starting point. Evolution would have no a priori knowledge of the fitness landscape. There is a large number of possible codes, so it would be incredibly lucky for evolution’s starting point to be anywhere near the special, canonical code we observe today. There would be an enormous evolutionary distance to travel between an initial random starting point, and the code we observe.
And yet there is not even so much as a trace of such a monumental evolutionary process. This would be an incredible convergence. In biology, when we see convergence, we usually also see variety. The mammalian and cephalopod eyes are considered to be convergent, but they also have fundamental differences. And in other species, there are all kinds of different vision systems. The idea that the universal DNA code is the result of convergence would be very suspect. Why are there no other canonical codes found? Why are there not more variants of the code? To have that much evolutionary distance covered, and converge with that level of precision would very strange.
And of course, in addition to this strange absence of any evidence of such a monumental evolutionary process, there is the problem described above with evolving the code to begin with. The code’s fitness landscape is rugged and loaded with many local minima. Making much progress at all in evolving the code would be difficult.
But then there is Observation #3.
Not only do we not see traces of the required monumental process of evolving the code across a great distance, and not only would this process be almost immediately halted by the many local minima in the fitness landscape, but what fitness improvements could actually be realized would not likely be selected for because said improvements rarely actually confer there benefit.
While these problems obviously are daunting, we have so far taken yet another tremendous problem for granted: the creation of the initial code, as a starting point.
We have discussed above the many problems with evolving today’s canonical code from some starting point, all the while allowing for such a starting point simply to magically appear. But that, alone, is a big problem for evolution. The evolution of any code, even a simple code, from no code, is a tremendous problem.
Finally, a possible explanation for these several and significant problems to the evolution of the DNA code is the hypothesis that the code did not actually evolve so much as construct. Just as the right sequence of amino acids will inevitably fold into a functional protein, so too perhaps the DNA code simply is the consequence of biochemical interactions and reactions. In this sense the code would not evolve from random mutations, but rather would be inevitable. In that case, there would be no lengthy evolutionary pathway to traverse.
Now I don’t want to give the impression that this hypothesis is mature or fleshed out. It is extremely speculative.
But there is another, more significant, problem with this hypothesis: It is not evolution.
If true this hypothesis would confirm design. In other words, a chemically determined pathway, which as such is written into the very fabric of matter and nature’s laws, would not only be profound but teleological. The DNA code would be built into biochemistry.
And given Observation #2, it is a very special, unique, detailed, code that would be built into biochemistry. It would not merely be a mundane code that happened to be enabled or determined by biochemistry, but essentially an optimized code.
Long live Aristotle.
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