Analysis of synonymous codon usage in Zika virus.

Zika virus is a zoonotic pathogen, which have made frequent incursion into the human population in Africa and South East Asia over the course of several decades but never reached to the pandemic proportions until the most recent outbreak. Viruses are solely dependent on host synthetic machinery for their replication cycle; therefore, replication and persistence in a host species of different genetic background requires certain degree of adaptation. These adaptations are necessary to avoid detection from host immune surveillance and maximize the utilization of available resources for efficient viral replication. Study of genomic composition and codon usage pattern not only offer an insight into the adaptation of viruses to their new host, but may also provide some information about pathogenesis and spread of the virus. To elucidate the genetic features and synonymous codon usage bias in ZIKV genome, a comprehensive analysis was performed on 80 full-length ZIKV sequences. Our analyses shows that the overall extent of codon usage bias in ZIKV genome is low and affected by nucleotide composition, protein properties, natural selection, and gene expression level.