Figure 1From: Assortative mating and gene flow generate clinal phenological variation in treesSpatial settings of populations and environmental effects. Fifty-five populations of 500 individuals each were spread homogeneously on a 5×11 grid along 11 latitudinal positions. E(Y) represents the environmental effect at a given latitude Y and is scaled by k E (see equation 8). No selection was introduced: stabilizing selection was canceled with ω2 = 109 and all populations shared a phenotypic optimum Z opt  = 0.Back to article page