The Non-Universality of the Genetic Code
(And Its Implications)
by Rich Deem

Introduction

tRNA moleculeOriginal studies of the genetic code demonstrated that it was constant throughout the plant, protists, and animal kingdoms. It was taught (even in my college days) that the genetic code should be universal as predicted by the theory of evolution, since alterations of the genetic code would be lethal in those individuals that acquired genetic code Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations. Recently, many examples of variations in the genetic code have been discovered in many species of unrelated organisms. Although first shown in 1979 by Barrell et. al (1), subsequent studies have demonstrated that the genetic codes differs in diverse groups of unrelated animals, plants, and protists (2). There is no pattern of change in the code of related groups of organisms and none of the organisms that possess altered genetic code exhibit any form of evolutionary descent or common ancestry, which might imply that the genetic code had evolved.

Introduction to the genetic code and An organic compound made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.protein translation:

The molecule depicted on this page (Figure 1) is transfer Ribonucleic acid: a chemical that directs the manufacture of proteins and sometimes codes for the genetic material within certain organisms.RNA ( A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA). This molecule is responsible for translating messenger Ribonucleic acid: a chemical that directs the manufacture of proteins and sometimes codes for the genetic material within certain organisms.RNA ( Messenger ribonucleic acid is a molecule of RNA encoding a chemical 'blueprint' for a protein product, which is transcribed from a DNA template, and carries this information to the sites of protein synthesis.mRNA) to An organic compound made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.protein. A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.Amino acids are esterified (bound) to the 3' end of the molecule. The A sequence of three nucleotides in transfer RNA that binds to the complementary triplet (codon) in messenger RNA to specify an amino acid during protein synthesis.anticodon portion of the molecule binds to the complimentary A specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for encoding a specific amino acid into a polypeptide chain.codon of Messenger ribonucleic acid is a molecule of RNA encoding a chemical 'blueprint' for a protein product, which is transcribed from a DNA template, and carries this information to the sites of protein synthesis.mRNA, subsequently adding the A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.amino acid to the growing A compound consisting of two or more amino acids, the building blocks of proteins.peptide ( An organic compound made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.protein) chain. The A sequence of three nucleotides in transfer RNA that binds to the complementary triplet (codon) in messenger RNA to specify an amino acid during protein synthesis.anticodon site of the A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA molecule provides specificity to the genetic code, since each specific A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA's bind to a specific Messenger ribonucleic acid is a molecule of RNA encoding a chemical 'blueprint' for a protein product, which is transcribed from a DNA template, and carries this information to the sites of protein synthesis.mRNA A specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for encoding a specific amino acid into a polypeptide chain.codon The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequence. All organisms that differ from the "universal" genetic code do so through a single One of the structural components, or building blocks, of DNA and RNA. A nucleotide consists of a base plus a molecule of sugar and one of phosphate.nucleotide Replacement of one nucleotide in a DNA sequence by another nucleotide or replacement of one amino acid in a protein by another amino acid.substitution in the A sequence of three nucleotides in transfer RNA that binds to the complementary triplet (codon) in messenger RNA to specify an amino acid during protein synthesis.anticodonsite of the A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA. In all the examples given in this paper, this single One of the structural components, or building blocks, of DNA and RNA. A nucleotide consists of a base plus a molecule of sugar and one of phosphate.nucleotide Replacement of one nucleotide in a DNA sequence by another nucleotide or replacement of one amino acid in a protein by another amino acid.substitution causes the A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA to bind to a completely different mRNA A specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for encoding a specific amino acid into a polypeptide chain.codon (see Figure 2). Therefore, all Sequences of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for encoding a specific amino acid into a polypeptide chain.codons that coded for this one A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.amino acidwould now be substituted by another A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.amino acid. This kind of mutation would result in wholesale changes to all or nearly all of the Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteins of an organism, which would be lethal to 100% of these mutants.


Figure 2. Translation of same Messenger ribonucleic acid is a molecule of RNA encoding a chemical 'blueprint' for a protein product, which is transcribed from a DNA template, and carries this information to the sites of protein synthesis.mRNA by (A), wild type and (B), A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA mutant

Since evolution requires a process by which the genetic code would be altered, evolutionists propose that organisms that express a non-standard genetic code must be genetic mutants. The problem is that this single point A permanent structural alteration in DNA, consisting of either a substitution, insertion or deletion of nucleotide bases.mutation would result in an organism that could not survive (in fact, the fertilized ovum of such a mutant would be unable to undergo even one round of cell division). This is not just my opinion. Even proponents of evolution agree that 100% of these A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA mutants would be unable to survive. Dr. T. H. Jukes (University of California, Berkeley) has stated, "Any Relating to a permanent structural alteration in DNA, consisting of either a substitution, insertion or deletion of nucleotide bases.mutationalchange in the code would be lethal, because it would produce widespread alterations in the A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.amino acid The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequences of Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteins. Such changes would destroy An organic compound made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.protein function, and hence would be intolerable." What these scientists have really found to be "intolerable" is what these " Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations" disclose about the theory of evolution.

A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA "Mutants" of the "Universal" Genetic Code

What kinds of changes would A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutationsresult in? Table 1 describes a number of these A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA mutants, including the kinds of organisms and the changes in A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.amino acids coded for. One can see that many of these Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations substitute A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.amino acids that stabilize a-helical structures (the most common tertiary structure in Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteins) for those that destabilize a-helical structures or, alternatively, those that destabilize a-helical structures for those that stabilize a-helical structures. A Replacement of one nucleotide in a DNA sequence by another nucleotide or replacement of one amino acid in a protein by another amino acid.substitution that changes the configuration of a An organic compound made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.protein is virtually guaranteed to destroy its function. It actually gets worse in other instances. In some of the genetic code mutants, former stop Sequences of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for encoding a specific amino acid into a polypeptide chain.codons (which cause An organic compound made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.protein translation to halt when the An organic compound made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.protein reaches the proper size) now code for A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.amino acids, which would result in longer Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteins. Although many Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteinsundergo post-translational modification, those that don't undergo post-translational modification will undergo conformational changes resulting in inactivation of function. The most lethal of all these mutants would be the ones that changed from coding for arginine to coding for the stop The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequence. This mutant would produce Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteins with very short polypeptide chains, since An organic compound made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteintranslation would stop at every instance where arginine (AGR) was coded. Some Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteins would not be made at all and virtually all other Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteins would be non-functional.

Table 1. tRNA "Mutants" of the "Universal" Genetic Code
"Mutant" Code ("Normal" amino acid) Stabilize a-helix? "Mutant" amino acid ("Universal" Code) Stabilize a-helix? Where "mutant" found
AUA (isoleucine) no methionine (AUG) yes human mitochondria
UGA (stop) N/A tryptophan (UGG) yes human mitochondria
UGA (stop) N/A tryptophan (UGG) yes Mycoplasma spp.
UAA and UAG (stop) N/A glutamine (GAA, GAG) no ciliated protozoa, Acetabularia
UGA (stop) N/A cysteine (UGC, UGU) yes E. octacarinatus
CUG (leucine) yes serine (UCN) no Candida spp.
CUN (leucine) yes threonine (ACN) no yeasts
AAA (lysine) no asparagine (AAU, AAC) yes platyhelminths and echinoderms
UAA (stop) N/A tyrosine (UAU, UAC) yes planaria
AGR (arginine) no serine (AGU, AGC) no several animal orders
AGR (arginine) no stop (UGA, UAA, UAG) N/A some vertebrates
A = Adenine C = Cytosine G = Guanine U = Uracil N = Adenine and Guanine R = Cytosine or Uracil

The evidence is overwhelming and the problem an extremely profound one. The scientific community and even the community of creationary scientists, despite its obvious implications, have largely ignored this problem. Those who have proposed evolutionary explanations have done so using mechanisms that are so improbable as to be statistically impossible. Here is their explanation:

The Problem of Mechanism

Here is the essence of what evolutionists are proposing. They propose that every instance of a specific A specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for encoding a specific amino acid into a polypeptide chain.codon in the Deoxyribonucleic acid: the chemical inside the nucleus of a cell that carries the genetic instructions for making living organisms.DNA is mutated and replaced by another A specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for encoding a specific amino acid into a polypeptide chain.codon. This requires replacement of 1-5% of the entire genetic The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequence of an organism. Although this doesn't seem like a large amount of the All the DNA contained in an organism or a cell, which includes both the chromosomes within the nucleus and the DNA in mitochondria.genome, it is the specificity of replacement that makes this mechanism statistically impossible. In the case of vertebrates, this replacement would involve the specific replacement of millions of One of the structural components, or building blocks, of DNA and RNA. A nucleotide consists of a base plus a molecule of sugar and one of phosphate.nucleotidepairs. There is no "directional A permanent structural alteration in DNA, consisting of either a substitution, insertion or deletion of nucleotide bases.mutation pressure" that would cause only one A specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for encoding a specific amino acid into a polypeptide chain.codon The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequence to be replaced in an organism, even according to evolutionary theories. Evolution states that selection acts on the An organic compound made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteinstructure to improve its function. Since we are talking about all the Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteins in an organism, there is no one selective pressure that would work to improve the function of all Organic compounds made of amino acids arranged in a linear chain, joined together by peptide bonds between the carboxyl and amino groups of the adjacent amino acid residues.proteins simultaneously (especially by substituting only one specific A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.amino acid for another). It would make much more sense from an evolutionary viewpoint that The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.gene duplication of A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA would occur, followed by A permanent structural alteration in DNA, consisting of either a substitution, insertion or deletion of nucleotide bases.mutation of the duplicated A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA and gradual conversion of genetic The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequences from those that bound to the universal A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA to those that bound the mutant A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA. However, such a scenario would be expected to produce intermediate forms of organisms (possessing both forms of A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA), since the process would obviously be a long one. Even though there are dozens of examples of A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA mutants, none of them exist as these hypothetical intermediates, indicating that this is not a reasonable mechanism.

The Problem of Descent

The existence of genetic code mutants in diverse groups of unrelated organisms presents a significant problem in evolutionary theory. Since all life must be related to their relatives, the genetics must reflect this fact. These mutants present a glaring problem in terms of descent. One would expect that related organisms would exhibit some form of evolutionary tree in regard to the genetic code mutants. Instead, what we find are randomly isolated individual species of organisms which possess these genetic code Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations. If the mechanism for producing these Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations was evolution, we would expect to find whole families and orders of organisms with these kinds of Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations. Alternatively, we must accept that all of these Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations occurred relatively recently, such that there would be no record of descent.

Conclusion Top of page

In conclusion, there is no reasonable evolutionary mechanism by which A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA point Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations can occur in such a diversity of organisms. Evolutionists must believe in a magical directional A permanent structural alteration in DNA, consisting of either a substitution, insertion or deletion of nucleotide bases.mutation pressure that replaces all of one specific A specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for encoding a specific amino acid into a polypeptide chain.codon The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequence in a variety of unrelated species. In addition, they must believe that none of these species have evolved once this A permanent structural alteration in DNA, consisting of either a substitution, insertion or deletion of nucleotide bases.mutation occurred, since there is no evidence of descent. The alternative, that a Creator designed A small RNA molecule that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis.tRNA "mutants" to show us that He and not blind chance is responsible for life, is intolerable to those whose "faith" is evolution.


The Cell's Design: How Chemistry Reveals the Creator's ArtistryFazale Rana (Ph.D. in chemistry), vice president of research and apologetics at Reasons To Believe, has written a new book, The Cell's Design: How Chemistry Reveals the Creator's Artistry, that attempts to show that cellular biochemistry points to the existence of the Creator who designed it. Whereas most intelligent design books attempt to show the existence of design by demonstrating the existence of irreducible complexity, Dr. Rana examines the cell's biochemistry with broad strokes of how everything works together with such marvelous fidelity. So, even if a single piece or line of evidence might be dismissed as a statistical outlier, the weight of evidence makes a powerful case for design by a Creator.


References Top of page

  1. G. Barrell, A. T. Bankier, and J. Drouin. 1979. Nature [London] 282: 189-194.
  2. Osawa S. Jukes TH. Watanabe K. Muto A. 1992. Microbiological Reviews 56 (1): 229-64.

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