Tuesday, January 4, 2022

Reading the Genetic Code

Imagine a software code of 0s and 1s in a long string, and imagine that if you read off each digit in sequence the string coded for a particular meaning, but if you only read off every third digit the string coded for a completely different meaning. Now imagine the improbability of such a code being produced by random combinations of 0s and 1s by completely mindless processes and forces.

If you do this little thought experiment, you get some idea of the complexity of the DNA code in the nuclei of every cell of our bodies, and why so many people not committed a priori to naturalistic materialism believe that the code had to be the product of an intelligent mind.

DNA is not quite like the preceding example, but it does have overlapping codes whose regulation is carried out by a complex of proteins which themselves couldn't have existed until the code for them existed. But the code couldn't have come about until the proteins were available to allow the code to be read.

An article by biologist Ann Gauger at Evolution News discusses this property of what biologists call "alternative reading frames." She uses this graphic to illustrate:


Gauger goes on to explain:
If you look at the figure ... you’ll see the sequence of DNA from a human mitochondrion: AAATGAACGAAA and so on. Above in red you see the nucleotides (ATCG) have been grouped in threes, and a letter assigned to each. Each group of three is a codon, and each unique codon specifies a particular amino acid, indicated by the red letters: K W T K I, etc. That is the protein sequence that the DNA specifies for that particular way of reading the DNA.

That way of reading the DNA, with that set of groups of three, is called a reading frame, because it establishes the frame for the way we read the information in the gene. In this case it encodes the protein ATP8.

If DNA were a human code, then it would be inconceivable to have a code that could be read in more than one frame at a time. By this I mean starting at one nucleotide and getting one sequence and starting at another nucleotide and getting another sequence with a different meaning.

But that is exactly what happens in this stretch of mitochondrial DNA. Look below the nucleotides to a different set of letters in blue. Notice that they are offset from the first reading frame by two nucleotides. This changes the way the nucleotides are read. The first codon is ATG, the second AAC, and so on. And the resulting protein, ATP6, has a very different sequence from that of the first, ATP8.
That's not all. DNA is double-stranded and when the strands separate in order to be read it's possible that both be read simultaneously, one forward and one backward, so that six different proteins can be coded for by a single segment of DNA.

This is an absolutely stupefying level of complex information. It's an incredibly ingenious solution to the problem of packing maximum information into the shortest possible code, and the notion that it could've come about in some primordial environment as a result of eons of blind, undirected chance requires herculean credulity.

The simplest and most plausible explanation for the complexity of the DNA code is that it was engineered by an intelligence, and the only way to avoid that conclusion is to eliminate any possibility of such an intelligence at the very outset, to decide that no such intelligence exists and that therefore the DNA code must have been generated by blind impersonal forces no matter how improbable that would be.

But why decide that? What reason can be adduced to rationally justify such a decision? Why assume that no such agent exists when the existence of such a being would explain so much, not just about DNA, but about the world and life generally?

The only reason anyone makes that assumption is, it seems, that they have a strong psychological or emotional preference that no such being exist and they allow that preference to shape everything else they believe.

The conclusion that an intelligent agent must've been involved in the development of the structure of the DNA code certainly seems warranted by the evidence. The big question, then, is what might be the nature of the intelligent agent that designed and created this code? Who or What might it be?

Wouldn't these questions be important to think about?