Figure 2From: A new look at an old virus: patterns of mutation accumulation in the human H1N1 influenza virus since 1918Mutation accumulation in H1N1 in deeper time. The published Brevig Mission strain from 1918 was used as the baseline for comparison with all available human H1N1 genomes. There are two distinct trend lines in the data. The 2009–2010 outbreak samples and additional samples from 2011–2012 are circled.Back to article page