Figure 1
From: No evidence for assortative mating within a willow warbler migratory divide
Genetic ancestry based on two subspecies-specific markers. Bayesian assignment probability (genetic ancestry) to a northern (acredula) subspecies population cluster for all individuals computed in STRUCTURE (n = 181; details listed in Additional file 1: Table S2). Reference samples for the southern (P. t. trochilus, n = 18, open bars) and northern (P .t. acredula, n = 15, black bars) subspecies were plotted separately from the samples collected in the hybrid zone (n = 148, grey bars). Each bar represented one individual; the y-axis represented the probability of genetic ancestry to the northern subspecies cluster. The distribution within the study population in the hybrid zone was skewed towards southern genotypes. Dashed lines in the hybrid zone population indicated mean ancestry estimates for individuals from the northern and southern reference sets, respectively.