Effective number of codons (abbreviated as ENC or ''Nc'') is a measure to study the state of
codon usage bias
Codon usage bias refers to differences in the frequency of occurrence of synonymous codons in coding DNA. A codon is a series of three nucleotides (a triplet) that encodes a specific amino acid residue in a polypeptide chain or for the terminati ...
es in genes and genomes. The way that ENC is computed has obvious similarities to the computation of
effective population size
The effective population size (''N'e'') is a number that, in some simplified scenarios, corresponds to the number of breeding individuals in the population. More generally, ''N'e'' is the number of individuals that an idealised population w ...
in
population genetics
Population genetics is a subfield of genetics that deals with genetic differences within and between populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and pop ...
. Although it is easy to compute ENC values, it has been shown that this measure is one of the best measures to show codon usage bias.
Since the original suggestion of the ENC, several investigators have tried to improve the method, but it seems that there is much room to improve this measure.
References
Molecular biology
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