Expansion patterns in mismatch distributions for temperate North American populations of Daphnia rosea. The distribution of pairwise haplotype differences (number of differences) within the major mitochondrial clade (A) and the major nuclear clade (B) of North American populations. Black line indicates the observed distribution. Red line indicates the expected distribution based on the spatial expansion model. Light blue zone indicates the 95% CI range of expected distribution based on the spatial expansion model. The nuclear distribution lacks the 95% CI range, because the least-square fitting algorithm in ARLEQUIN failed to converge.