Influenza A virus (IAV) has been a major concern worldwide as a cause of high mortality and morbidity. In the present study, the complete coding regions of viral neuraminidase (NA) gene of IAV subtype H1N1 reported from India were analyzed for the possible codon usage bias using statistical and bioinformatics tools. A total of 34 NA coding sequences were used in the study. The results show a low bias in the coding region of the NA gene sequences. The RSCU values suggest a very low preference of the codons having dinucleotide CpG whereas most of the codons showed a preferred use of the dinucleotides CpA and TpA. The results suggest that there exists a balance between mutational pressure and natural selection to shape the codon usage bias in the IAV subtype which helps the virus adapt to different host conditions.
