Codon Bias is the tendency for an organism or virus to make use of certain codons more than the others to encode a particular amino acid. A significant detrminant of codon bias is the guanosine-cytosine (GC) content of genome. An organism which has a relatively low G+C content of 30% will be less likely to have a G or C at the third position of the codon (wobble position) than a A or T to specify the amino acid which can be represented by more than the one codon.