Creation Moment 9/19/2024 - Duons & tRNAs

I will praise Thee; for I am fearfully and wonderfully made:
marvellous are Thy works;
Psalm 139:14

"Researchers over the past decade have been characterizing new, previously hidden genetic codes embedded within the same sections of genes that code for proteins—utterly defying all naturalistic explanations for their existence.

This same linear sequence of genetic information that encodes multiple programming languages with different instructions is truly evidence of supernatural engineering that can only be ascribed to the all-powerful and all-wise Creator.

Protein-coding genes contain key information to make proteins and contain the most studied type of genetic code. Some of the most important chunks of code in protein-coding genes, called exons, are those segments that specify the actual template for protein sequences.

In exons, three consecutive DNA letters form what is called a codon, and each codon corresponds to a specific amino acid in a protein.

Long sets of codons in genes contain the protein-making information that ends up being represented in an RNA copy of the gene used to translate (create) entire proteins, which may be hundreds of amino acids in length, using cellular machinery (ribosomes).

In the early days of molecular biology, when the genetic code was being deciphered, codons initially appeared to possess some redundancy. This was because there are 61 codons in contrast to only 20 amino acids. As far as specifying a particular amino acid, the first two bases in the codon structure are the same, but the third base can vary.

For example, the codons GGU, GGC, GGA, and GGG all encode the same amino acid called glycine. When scientists first discovered this phenomenon, they called the variation in the third base a “wobble”
and, out of ignorance, simply relegated the variability as redundant or degenerate. In other words, they assumed that all the different codon variants for a given amino acid were functionally equivalent.

Until recently, scientists believed that the protein-coding regions of genes had mysterious signals other than codons that told the cell machinery how to regulate and process the RNA transcripts (copies of genes) prior to making the protein. Researchers originally thought that these regulatory codes and the protein template codes containing the codons operated independently of each other, but they no longer think this. These codes are embedded in the “wobble” base.

In 2013, a study was published in which researchers mapped the locations of where transcription factors were binding in active genes. They were surprised to discover that a significant proportion of the binding sites contained codons and that the third base in a codon contained information for the binding of a specific type of transcription factor in addition to coding for an amino acid. This initial discovery of a dual-use codon was labeled a duon. In humans, they discovered that about 15% of codons were dual-use codons, or duons.

This research showed that multiple overlapping or parallel codes in exons not only exist but also that these codes actually work both separately and together.

To summarize this remarkable discovery, the researchers said, “Our results indicate that simultaneous encoding of amino acid and regulatory information within exons is a major functional feature of complex genomes,” and the “information architecture of the received genetic code is optimized for superimposition of additional information.”

So, not only does a codon provide the information for which specific

amino acid to add in the making of a protein, but the variant of that codon also influences the information needed to regulate its folding at multiple levels. Thus, you have two different sets of information encoded in different languages in the same section of DNA. The researchers of the translation pausing paper note, “Dual interpretations enable the assembly of the protein’s primary structure while enabling additional folding controls via pausing of the translation process.” What was once thought to be meaningless redundancy or wobble has now been proven to be exactly the opposite.

Another discovery in 2016 showed that the third base of codons regulates rates of gene transcription, levels of mRNA copies made from a gene, and the corresponding amounts of protein produced. In other words, the amount of mRNA output produced from a gene is directly related to the specific DNA sequence in codons.

Gene output must be highly controlled and regulated in the cell, just like a cruise control mechanism in a car regulates its speed. If genes are not properly regulated, cellular dysfunction would result in disease or death. In addition to the many other types of DNA codes in and around genes that control transcription, now it is known that the specific sequence of codons, including the third base, plays a key role in gene regulation by controlling the rate of transcription.

Transfer RNAs (tRNAs) are specialized adaptor molecules composed of RNA, typically 76 to 90 nucleotides in length, that serve as the physical link between the mRNA and the amino acid sequence of proteins. The tRNAs do this by carrying a specified amino acid to the protein-synthesizing machinery—the ribosome. The complementation of a three-nucleotide codon in an mRNA by a three-nucleotide anticodon in the tRNA attached to the specified amino acid enables protein synthesis at the ribosome based on the mRNA code.

Like factories that make multiple products, all the assembly lines need a steady supply of the correct parts, and the processes involved in doing that need to be perfectly orchestrated. The tRNAs are the key parts in the protein assembly process that provide the correct amino acids at the ribosome when a protein is being synthesized. This complex coordination and resource distribution is affected by the third base in codons. Thus, the third base of a codon must be accurately coded or fine-tuned to produce the correct amount of a specified protein." 

ICR