Figure 5.

The average number of viruses is proportional to the number of independent clusters. The total number of viruses (green curve) and of lineages (red curve) as a function of time for ${\overline{f}}_i={10}^{-3}$, $\mu ={10}^{-2}$, $\sigma /d=3\times {10}^{-3}$. The initial single lineage splits into two lineages at $t\approx 59$ years and then into three lineages at $t\approx 67$ years (dashed vertical lines), and the number of viruses first doubles and then triples following the lineage splittings.