Figure 4. Occurrence and distribution of the 31 genetic clusters in the seven water systems and three individual lakes (Saxvattnet, Rörvattnet, Ånnsjön). Pie diagrams show the representation of populations in the present (leftmost diagram in each pair) and the past samples (rightmost diagram; detailed illustration of the genetic clusters in each system are provided in Figure S1). Estimates of effective population size measured as N eV are indicated for each population occurring at both points in time. Black arrows indicate direction of water flow. Note the presence of “new” populations in the present samples from Skåarnja 1 (Lake Daimanjaure) and Hotagen 1 (Lake Munsvattnet).