Amazing stuff! This research is like the proverbial looking for the needle in a haystack!
"... In addition to finding five new alternate genetic codes, the team also verified seven others that had been discovered one-by-one in the past, bringing the total number of known exceptions in bacteria to 12. ...
developed an algorithm called Codetta—named after the Rosetta Stone—that can screen an organism’s genome and predict which amino acids its codons will add into a given protein. The algorithm quickly screens a genome and compares it to the organism’s proteins in a database called Pfam. If enough variations from the standard code appear in a consistent manner, Codetta flags the organism as potentially using an alternate amino acid for a particular codon ...
Exceptions to the standard genetic code have been found in single-celled eukaryotes such as yeast, but experts expect alternate codes to be rare in more complex eukaryotic organisms. ..."
developed an algorithm called Codetta—named after the Rosetta Stone—that can screen an organism’s genome and predict which amino acids its codons will add into a given protein. The algorithm quickly screens a genome and compares it to the organism’s proteins in a database called Pfam. If enough variations from the standard code appear in a consistent manner, Codetta flags the organism as potentially using an alternate amino acid for a particular codon ...
Exceptions to the standard genetic code have been found in single-celled eukaryotes such as yeast, but experts expect alternate codes to be rare in more complex eukaryotic organisms. ..."
From the abstract:
"The genetic code has been proposed to be a ‘frozen accident,’ but the discovery of alternative genetic codes over the past four decades has shown that it can evolve to some degree. Since most examples were found anecdotally, it is difficult to draw general conclusions about the evolutionary trajectories of codon reassignment and why some codons are affected more frequently. To fill in the diversity of genetic codes, we developed Codetta, a computational method to predict the amino acid decoding of each codon from nucleotide sequence data. We surveyed the genetic code usage of over 250,000 bacterial and archaeal genome sequences in GenBank and discovered five new reassignments of arginine codons (AGG, CGA, and CGG), representing the first sense codon changes in bacteria. In a clade of uncultivated Bacilli, the reassignment of AGG to become the dominant methionine codon likely evolved by a change in the amino acid charging of an arginine tRNA. The reassignments of CGA and/or CGG were found in genomes with low GC content, an evolutionary force that likely helped drive these codons to low frequency and enable their reassignment."
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