I will praise thee; for I am fearfully and wonderfully made: Psalm 139:14
These originals were used in “inventive biosynthetic processes” to synthesize the other amino acids. The code then adapted to accommodate these new amino acids.
Similarities in the codons of related amino acids were subject to computer analysis in order to determine if a better code could be found based on biosynthetically related amino acids. An extraordinary correlation was noted for the universal code, as against 32,000 randomly generated possibilities. Changing the pattern of relatedness among amino acids gave more codes equal to or of greater correlations than the universal code. However, the authors stated that these observations “cannot be used as proof for the biosynthetic theory of the genetic code”.
Less than half of the 20 canonical amino acids found in proteins can be synthesized from inorganic molecules. Furthermore, the amino acids that are missing (the so-called secondary amino acids) are also missing from material recovered from meteorites.
This is problematic for evolution, for it implies that early life-forms on this planet could only use ten amino acids for protein construction, something which we don’t observe today, thereby greatly reducing the possible number of functional proteins.
The primary amino acids were coded by an ancestral genetic code, which then expanded to include all 20 canonical amino acids. The present code is a non-random structure yet it is more robust as far as translational errors are concerned than the majority of alternative codes that can be generated conceptually according to accepted evolutionary trajectories.
Several questions present themselves here, however.
--Why don’t we find any protein sequences in the fossils of ancient organisms, which only have primary amino acids? The fact that no such proteins exist is strong proof against the evolutionary origin of the genetic code. We only find proteins made up of all 20 amino acids.
--Why didn’t the genetic code keep on expanding to cover more than 20 amino acids? Why not 39, 48 or 62?
--Why did codon triplets evolve, and why not quadruplets? With 44 = 256 possible codon quadruplets, coding space could have increased, and thus a much larger universe of possible proteins could have been made possible.
An additional fundamental issue is that if life commenced in an RNA world, then amino acids could have been synthesized on the primitive codons associated with these molecules by primordial synthetases.
--How do similar coding rules now apply when codon recognition is performed by the anticodons of the tRNA with the assistance of the highly specific aminoacyl-tRNA-synthetases that attach to the amino acids?" CMI
The co-evolution theory
"According to the co-evolution theory, the original genetic code was “excessively degenerate” meaning it could code for several amino acids.These originals were used in “inventive biosynthetic processes” to synthesize the other amino acids. The code then adapted to accommodate these new amino acids.
Similarities in the codons of related amino acids were subject to computer analysis in order to determine if a better code could be found based on biosynthetically related amino acids. An extraordinary correlation was noted for the universal code, as against 32,000 randomly generated possibilities. Changing the pattern of relatedness among amino acids gave more codes equal to or of greater correlations than the universal code. However, the authors stated that these observations “cannot be used as proof for the biosynthetic theory of the genetic code”.
Less than half of the 20 canonical amino acids found in proteins can be synthesized from inorganic molecules. Furthermore, the amino acids that are missing (the so-called secondary amino acids) are also missing from material recovered from meteorites.
This is problematic for evolution, for it implies that early life-forms on this planet could only use ten amino acids for protein construction, something which we don’t observe today, thereby greatly reducing the possible number of functional proteins.
The primary amino acids were coded by an ancestral genetic code, which then expanded to include all 20 canonical amino acids. The present code is a non-random structure yet it is more robust as far as translational errors are concerned than the majority of alternative codes that can be generated conceptually according to accepted evolutionary trajectories.
Several questions present themselves here, however.
--Why don’t we find any protein sequences in the fossils of ancient organisms, which only have primary amino acids? The fact that no such proteins exist is strong proof against the evolutionary origin of the genetic code. We only find proteins made up of all 20 amino acids.
--Why didn’t the genetic code keep on expanding to cover more than 20 amino acids? Why not 39, 48 or 62?
--Why did codon triplets evolve, and why not quadruplets? With 44 = 256 possible codon quadruplets, coding space could have increased, and thus a much larger universe of possible proteins could have been made possible.
An additional fundamental issue is that if life commenced in an RNA world, then amino acids could have been synthesized on the primitive codons associated with these molecules by primordial synthetases.
--How do similar coding rules now apply when codon recognition is performed by the anticodons of the tRNA with the assistance of the highly specific aminoacyl-tRNA-synthetases that attach to the amino acids?" CMI
