ABSTRACT
A protein can be encoded by a prodigious number of nucleotide sequences. A context effect is a functional interaction between distinct sites in messenger ribonucleic acid (mRNA); namely, a codon and its neighboring nucleotides. Context may have immediate translational effects; on the frequency of missense, frameshift, and chain loss errors. Context may also be subtle, triggering a chain of events that ultimately affect expression by another route. For example, differences in translational rate alter ribosomal distribution, which may conceivably lead to effects on mRNA synthesis and decay. It follows easily that if nucleotide context differentially affects transfer ribonucleic acid (tRNA) selection, it will affect the mistaken substitution of one tRNA for another. There is evidence for context effects on missense error frequencies. Relatively unperturbed tRNA-tRNA interfaces differ roughly 9-fold in the rate of tRNA selection they permit.
