Evolution of influenza viral neuraminidase (NA) revealed by large-scale sequence analysis

摘要

The influenza virus exhibits complicated evolutionary dynamics due to multiple reasons, such as diverse hosts, high mutation rates, and rapid replications. In this study, large-scale analyses of 11 454 influenza neuraminidase (NA) sequences revealed influenza A and B NA genes diverged first around 2641 years ago, and subsequently the NA subtypes of influenza A emerged around 1125 years ago. All nine NA subtypes of influenza A were genetically distinct from each other, with a total of 23 lineages identified. In addition, five and three sub-lineages were further identified in lineage 1A of NA1 and lineage 2B of NA2, respectively. The majority of lineages and sub-lineages were found to be host or geographic specific. This study provides not only a better understanding of influenza NA evolution, but also a database of lineages and sub-lineages that can be used for early detection of novel genetic changes for improved influenza surveillance.