Figure 1

Possible modes of distribution of drug-resistance phenotypes. Responses to quinine are presumed to be continuous and unimodal, while atovaquone (and chloroquine) may show bimodal character with parasite isolates falling into two distinct groups (characterized by low IC₅₀ or high IC₅₀,), each with their own distribution and variance. Courtesy of Michael Ferdig and Xin-Zhuan Su.