Fig. 2

How the threshold starting frequency of β^C required to prevent the invasion of β^S varies with different malaria mortality functions. The starting frequency of β^S was always 0.3 %. β^S was deemed to have failed to successfully invade the population if its frequency (q) was <(1/300) after 15,000 years of evolution. Each panel shows how the minimum starting frequency of β^C required to prevent β^S invading varies with different values of γ (x axis). In a, function f ₁ has been applied; in b, function f ₂ is used. In both panels, the red line indicates the case where malaria mortality is linked to β^C frequency (u = p) and the blue line indicates the case where malaria mortality is linked to β^S frequency (u = q). Baseline mortality rates and malaria susceptibilities of each genotype are given in tables S1 and S2