Proportion of pairs of identical sequences observed in EWA and WWA that were first observed in WWA. In c and f , the lines correspond to LOESS curves on the logarithmic scale. In b and e , P values calculated using Wilcoxon tests are as follows: *** P < 0.0001, ** P < 0.001, * P < 0.05; NS, P ≥ 0.05. In b , W within,adjacent = 6,195 ( P = 3.7 x 10 -12 ) and W adjacent,non-adjacent = 65,542 ( P < 2.2 x 10 -16 ). In e , for within EWA, W within,adjacent = 120.5 ( P = 6.7 x 10 -6 ) and W adjacent,non-adjacent = 4,555.5 ( P = 4.0 x 10 -6 ). For within WWA, W within,adjacent = 95 ( P = 9.9 x 10 -7 ) and W adjacent,non-adjacent = 3626 ( P = 1.1 x 10 -4 ). For between EWA and WWA, W = 2,719 ( P = 0.17). For a and d , maps were generated using shapefiles from the US Census Bureau 44 .
