Comparative genomics of Japanese encephalitis virus shows low rates of recombination and a small subset of codon positions under episodic diversifying selection

PLoS Negl Trop Dis. 2024 Jan 31;18(1):e0011459. doi: 10.1371/journal.pntd.0011459. eCollection 2024 Jan.

Abstract

Orthoflavivirus japonicum (JEV) is the dominant cause of viral encephalitis in the Asian region with 100,000 cases and 25,000 deaths reported annually. The genome is comprised of a single polyprotein that encodes three structural and seven non-structural proteins. We collated a dataset of 349 complete genomes from a number of public databases, and analysed the data for recombination, evolutionary selection and phylogenetic structure. There are low rates of recombination in JEV, subsequently recombination is not a major evolutionary force shaping JEV. We found a strong overall signal of purifying selection in the genome, which is the main force affecting the evolutionary dynamics in JEV. There are also a small number of genomic sites under episodic diversifying selection, especially in the envelope protein and non-structural proteins 3 and 5. Overall, these results support previous analyses of JEV evolutionary genomics and provide additional insight into the evolutionary processes shaping the distribution and adaptation of this important pathogenic arbovirus.

MeSH terms

  • Codon
  • Encephalitis Virus, Japanese* / genetics
  • Encephalitis, Japanese*
  • Genomics
  • Humans
  • Phylogeny
  • Recombination, Genetic

Substances

  • Codon

Grants and funding

Australian Department of Agriculture, Fisheries and Forestry for funding (Grant C08586). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.