GENETIC CODE:
The genetic code is the set of rules by which information encoded in genetic material (DNA ormRNA sequences) is translated into proteins (amino acid sequences) by living cells. The code defines a mapping between tri-nucleotide sequences, called codons, and amino acids. With some exceptions,[1] a triplet codon in a nucleic acid sequence usually specifies a single amino acid. Because the vast majority of genes are encoded with exactly the same code ), this particular code is often referred to as the canonical or standard genetic code, or simplythe genetic code, though in fact there are many variant codes. Thus the canonical genetic code is not universal. In humans, for example, protein synthesis in mitochondria relies on a genetic code that varies from the standard genetic code.
Not all genetic information is stored using the genetic code. All organisms' DNA contains regulatory sequences, intergenic segments, and chromosomal structural areas that can contribute greatly to phenotype. Those higher-level or epigenetic elements operate under sets of rules that are distinct from the codon-to-amino acid paradigm underlying the genetic code.
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