Population assignment proportions per individual based on results from structure for K = 2-7. Recent wild x domestic hybrids, sampled in the field as wild boar, are delimited by vertical lines. Results for K = 5 were not ambiguous across runs. Majority rule results (n = 10) are presented here, but the inclusion of E-Rhine in Kirchhellen at K = 5 is not fully supported, as various alternative clustering patterns were also inferred. Evanno’s method favoured optimal partitioning at K = 7 (see Additional file 5).