Bayesian Structure results showing the individual membership of the samples from 12 Romanian rivers populations (K = 4). Each individual is represented by a vertical line partitioned into segments according to the proportion of the genome assigned to each of the identified clusters. Vertical line-the membership coefficient (Q), horizontal line-individuals. The populations are grouped from east to west as follows: (1) − Uz, (2) − Oituz, (3) − Ucea, (4) − Cârțișoara, (5) − Porumbacu, (6) − Avrig, (7) − Topolog, (8) − Sebeșel, (9) − Bistra Mărului, (10) − Craiului, (11) − Bârzava, (12) − Caraș.