One hundred and thirty-two complete sequences of RABV ‘G’ gene were obtained from GenBank (Table 1). In addition, forty invariant gene like ‘N’ of RABV was used to analyze its codon usage in order to substantiate the analysis (Supplementary Table 1). Relative synonymous codon usage (RSCU) was first proposed in 1986 after which it has been extensively used in calculating codon usage bias of genes (Sharp and Li, 1986). The value of RSCU is directly proportional to the codon frequency and is calculated as described previously (Kumar et al., 2015). RSCUN1 suggests more frequency of codon bias while RSCUb1 indicates less frequency of codon bias.