Factors Contributing to Genetic Variability in the Y-domain of HEV

Hepatitis E virus (HEV) is the causative agent of Hepatitis E infections across the globe. Information regarding the factors involved in the genetic variability of the non-structural HEV Y-domain region (YDR) remains elusive. Thus, our study is aimed to analyze the diversity of the Y-domain protein genes of HEV. We attempted detailed characterization of the factors that contribute to genetic diversity including mutational, entropy and selection pressure analyses. Different datasets were built and were used for further comparative analysis.

Phylogenetic analyses of Y-domain protein genes showed the segregation of host isolates into respective genotype categories. Our multiple sequence alignment based on Y-domain gene sequences comparison revealed the presence of both synonymous and non-synonymous mutations with high entropy values. Selection pressure analysis revealed the prevalence of negative selection in all the datasets. Our investigation showed biasness towards transition which suggested that transitional mutations are more favoured than transversions in the Y-domain protein genes. The gene ontology suggested the involvement of YDR in binding, replication and catalytic processes, which clearly indicated its essentiality in the pathogenesis of HEV.

The present data on genetic diversity of the non-structural Y-domain protein genes will probably enhance our information about the evolution, biology and adaptation of HEV.