Accessible Version:  Using Evolution to Understand Influenza

Influenza-Over-Time Project: The Influenza-Over-Time Project is a study of the hemagglutinin gene from 11 different influenza viruses isolated from people around the world between 1968 and 2003.

Tools in the database align the nucleotide sequences for all 11 strains to show similarities. The resulting alignment produces a 1,095-nucleotide-long consensus sequence. Any differences between the consensus and individual strains show up. When we study the portion of the consensus sequence between nucleotides 401 and 500, we find that 32 of the 100 nucleotides have changed at least once between the years 1968 and 2003.

Researchers can use the sequence alignment to build an evolutionary tree to summarize the relationships among the viruses.

The sequences in the database come from the following paper: Smith, D.J., et al. 2004. Mapping the antigenic and genetic evolution of influenza virus. Science 305:371–376.

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