Expanded Genetic Code Research Paper

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What is the Expanded Genetic Code?

By Jonas Wilson, Ing. Med.

There are 20 canonical amino acids that are encoded by the genetic code of nearly all known organisms. There are only very few exceptions. In order to add novel building blocks to this existing repertoire, unique aminoacyl-tRNA synthetase and tRNA pairs are required, in addition to the specific amino acid codon as well as a source of the amino acid. In terms of biological evolution, it is known that our ensemble of 20 amino acids has remained unchanged over a period of 3 billion years. This is demonstrated by the fact that all living organisms have adopted it.

While the possibility of amino acid to analog replacement could theoretically occur owing to the existence of analogs
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There is some redundancy in the code as most of the amino acids may be encoded by more than one codon. Moreover, the code can be expressed as RNA or DNA codons with the former being used during translation (i.e. creation of proteins) after acquiring its sequence of nucleotides from the latter during transcription (i.e. copying of DNA into mRNA).

While it may be regarded as a common language shared between nearly all organisms, the genetic code is imperative for the interpretation of genes and the production of proteins. In addition to this, it precisely guides how the genome is put together via a series of fundamental and biochemical constraints. This has allowed the code to be fairly refractory to change and enables it to shape how mutations that arise affect the evolution of the genome.

Changes anywhere within codon function must be capable of being tolerated genome-wide. This means that compensatory changes throughout the rest of the genome must occur if there are small changes to the genetic code. Random mutagenesis is unlikely to cause such stable changes. However, contemporary feats in engineering are enabling the possibility of making rational changes to the genetic code.

Expanding the genetic
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