Evolutionary stasis of M1 gene of human influenza A viruses and the possibility of their subtyping by restriction analysis of M1 gene polymerase chain reaction product

Abstract

Nucleotide (nt) and amino acid (aa) sequences of the M1 protein in 36 human influenza A viruses were analyzed. The neighbor joining tree of the nt sequences revealed several lineages associated with past epidemics of human influenza. However, the tree of aa sequences revealed only few specific lineages. This discrepancy in phylogeny between nt and aa sequences indicates that the M1 protein of human influenza A virus nearly reached an evolutionary stasis. A simple subtyping method of human influenza A viruses by restriction fragment length polymorphism (RFLP) analysis of MI gene polymerase chain reaction (PCR) products is discussed.