Origin and Design of the Genetic Code: A One-Two Punch for Creation
True confession: I am a sports talk junkie. It has gotten so bad that sometimes I would rather listen to people talk about the big game than actually watch it on TV.
So, in the spirit of the endless debates that take place on sports talk radio, I ask: What duo is the greatest one-two punch in NBA history? Is it:
- Kareem and Magic?
- Kobe and Shaq?
- Michael and Scottie?
Another confession: I am a science-faith junkie. I never tire when it comes to engaging in discussions about the interplay between science and the Christian faith. From my perspective, the most interesting facet of this conversation centers around the scientific evidence for God’s existence.
So, toward this end, I ask: What is the most compelling biochemical evidence for God’s existence? Is it:
- The complexity of biochemical systems?
- The eerie similarity between biomolecular motors and machines designed by human engineers?
- The information found in DNA?
Without hesitation I would say it is actually another feature: the origin and design of the genetic code.
The genetic code is a biochemical code that consists of a set of rules defining the information stored in DNA. These rules specify the sequence of amino acids used by the cell’s machinery to synthesize proteins. The genetic code makes it possible for the biochemical apparatus in the cell to convert the information formatted as nucleotide sequences in DNA into information formatted as amino acid sequences in proteins.
Figure: A Depiction of the Genetic Code. Image credit: Shutterstock
In previous articles (see the Resources section), I discussed the code’s most salient feature that I think points to a Creator’s handiwork: it’s multidimensional optimization. That optimization is so extensive that evolutionary biologists struggle to account for it’s origin, as illustrated by the work of biologist Steven Massey1.
Both the optimization of the genetic code and the failure of evolutionary processes to account for its design form a potent one-two punch, evincing the work of a Creator. Optimization is a marker of design, and if it can’t be accounted for through evolutionary processes, the design must be authentic—the product of a Mind.
Can Evolutionary Processes Generate the Genetic Code?
For biochemists working to understand the origin of the genetic code, its extreme optimization means that it is not the “frozen accident” that Francis Crick proposed in a classic paper titled “On the Origin of the Genetic Code.”2
Many investigators now think that natural selection shaped the genetic code, producing its optimal properties. However, I question if natural selection could evolve a genetic code with the degree of optimality displayed in nature. In the Cell’s Design (published in 2008), I cite the work of the late biophysicist Hubert Yockey in support of my claim.3 Yockey determined that natural selection would have to explore 1.40 x 1070 different genetic codes to discover the universal genetic code found in nature. Yockey estimated 6.3 x 1015 seconds (200 million years) is the maximum time available for the code to originate. Natural selection would have to evaluate roughly 1055 codes per second to find the universal genetic code. And even if the search time was extended for the entire duration of the universe’s existence, it still would require searching through 1052 codes per second to find nature’s genetic code. Put simply, natural selection lacks the time to find the universal genetic code.
Researchers from Germany raised the same difficulty for evolution recently. Because of the genetic code’s multidimensional optimality, they concluded that “the optimality of the SGC [standard genetic code] is a robust feature and cannot be explained by any simple evolutionary hypothesis proposed so far. . . . the probability of finding the standard genetic code by chance is very low. Selection is not an omnipotent force, so this raises the question of whether a selection process could have found the SGC in the case of extreme code optimalities.”4
Two More Evolutionary Mechanisms Considered
Life scientist Massey reached a similar conclusion through a detailed analysis of two possible evolutionary mechanisms, both based on natural selection.9
If the genetic code evolved, then alternate genetic codes would have to have been generated and evaluated until the optimal genetic code found in nature was discovered. This process would require that coding assignments change. Biochemists have identified two mechanisms that could contribute to coding reassignments: (1) codon capture and (2) an ambiguous intermediate mechanism. Massey tested both mechanisms.
Massey discovered that neither mechanism can evolve the optimal genetic code. When he ran computer simulations of the evolutionary process using codon capture as a mechanism, they all ended in failure, unable to find a highly optimized genetic code. When Massey ran simulations with the ambiguous intermediate mechanism, he could evolve an optimized genetic code. But he didn’t view this result as success. He learned that it takes between 20 to 30 codon reassignments to produce a genetic code with the same degree of optimization as the genetic code found in nature.
The problem with this evolutionary mechanism is that the number of coding reassignments observed in nature is scarce based on the few deviants of the genetic code thought to have evolved since the origin of the last common ancestor. On top of this problem, the structure of the optimized codes that evolved via the ambiguous intermediate mechanism is different from the structure of the genetic code found in nature. In short, the result obtained via the ambiguous intermediate mechanism is unrealistic.
As Massey points out, “The evolution of the SGC remains to be deciphered, and constitutes one of the greatest challenges in the field of molecular evolution.”10
Making Sense of Explanatory Models
In the face of these discouraging results for the evolutionary paradigm, Massey concludes that perhaps another evolutionary force apart from natural selection shaped the genetic code. One idea Massey thinks has merit is the Coevolution Theory proposed by J. T. Wong. Wong argued that the genetic code evolved in conjunction with the evolution of biosynthetic pathways that produce amino acids. Yet, Wong’s theory doesn’t account for the extreme optimization of the genetic code in nature. And, in fact, the relationships between coding assignments and amino acid biosynthesis appear to result from a statistical artifact, and nothing more.11 In other words, Wong’s ideas don’t work.
That brings us back to the question of how to account for the genetic code’s optimization and design.
As I see it, in the same way that two NBA superstars work together to help produce a championship-caliber team, the genetic code’s optimization and the failure of every evolutionary model to account for it form a potent one-two punch that makes a case for a Creator.
And that is worth talking about.
- The Cell’s Design: How Chemistry Reveals the Creator’s Artistry by Fazale Rana (book)
- “FYI: ID in DNA” by Fazale Rana (article)
- “The Genetic Code: Simply the Best” by Fazale Rana (article)
- “The Optimal Design of the Genetic Code” by Fazale Rana (article)
- New Insights into Genetic Code Optimization Signal Creator’s Handiwork by Fazale Rana
- “Mitochondria’s Deviant Genetic Code: Evolution or Creation?” by Fazale Rana (article)
- “Biochemical Synonyms Optimized, Part 1” by Fazale Rana (article)
- “Biochemical Synonyms Optimized, Part 2” by Fazale Rana (article)
- Steven E. Massey, “Searching of Code Space for an Error-Minimized Genetic Code via Codon Capture Leads to Failure, or Requires at Least 20 Improving Codon Reassignments via the Ambiguous Intermediate Mechanism,” Journal of Molecular Evolution 70, no. 1 (January 2010): 106–15, doi:10.1007/s00239-009-9313-7.
- F. H. C. Crick, “The Origin of the Genetic Code,” Journal of Molecular Biology 38, no. 3 (December 28, 1968): 367–79, doi:10.1016/0022-2836(68)90392-6.
- Hubert P. Yockey, Information Theory and Molecular Biology (Cambridge, UK: Cambridge University Press, 1992), 180–83.
- Stefan Wichmann and Zachary Ardern, “Optimality of the Standard Genetic Code Is Robust with Respect to Comparison Code Sets,” Biosystems 185 (November 2019): 104023, doi:10.1016/j.biosystems.2019.104023.
- Massey, “Searching of Code Space.”
- Massey, “Searching of Code Space.”
- Ramin Amirnovin, “An Analysis of the Metabolic Theory of the Origin of the Genetic Code,” Journal of Molecular Evolution 44, no. 5 (May 1997): 473–76, doi:10.1007//PL00006170.