Influenza virus: Being the most beneficial mutation is no guarantee of long-term genetic success, research finds

Wellcome Trust Sanger Institute scientists have used computer modelling to understand why some mutations in a virus gene rise to dominance and become ‘fixed’ in the genome of the virus, while others die out. Their findings were based upon real-world observations of the evolution of a human flu virus, using genome sequences collected over many years by researchers worldwide. The team studied mutations in the haemagglutinin gene of the human influenza virus A/H3N2, which latches the virus on to human cells during an infection. Using a computer model, the team identified three key factors that determine the long-term survival of a mutation. The three factors are: the benefit the mutation confers to the virus; the background of other mutations that were present in the gene when the mutation appeared; and the effect of subsequent competition from different versions of the same gene in sibling viruses. To test the influence of each of...