Estimates of linkage disequilibrium, arranged from highest to lowest values, with mean ± SD.

Linkage disequilibrium was calculated as pair-wise associations among all polymorphisms, and summarized below as the average percentage of polymorphisms that were significantly (p≤0.01) associated with each other. For AFLPs, differences in levels of linkage disequilibrium among all the groups were highly significant (p<0.0001), except among appalachiensis and glaucus (p = 0.053). For Z-linked genes, canadensis and appalachiensis were not significantly different from each other (p = 0.214) but they are both different from glaucus (p<0.0001).