Antigenic evolution over the course of the 40-year simulation. (A) Proportion of virus population composed of each antigenic cluster through time. (B) Antigenic distance from the initial phenotype (x = 0, y = 0) for each of 5,943 virus samples relative to time of virus sampling. Viruses were sampled at a constant rate proportional to prevalence, and coloring was determined from the antigenic map in Figure 2D.
Bedford et al. BMC Biology 2012 10:38 doi:10.1186/1741-7007-10-38