Sampling locations of wolves (small open circles) and wolf-dog hybrids (black triangles 1–8, see also <b>Table 1</b>) in Estonia (Taebla) and Latvia (Dikli), hunted during the winter period of 2008–2009.

<p>The approximate ranges of wolves are with dark green (Estonia) and light green (Latvia).</p

Bayesian analysis of wolf, dog and wolf-dog hybrid genotypes from Estonia and Latvia with the ‘parameter set A’ (<b>Table 2</b>).

<p>Analysis was based on 11 autosomal microsatellite loci using Structure v2.2, with the following parameters: <i>K</i> = 2 clusters; ‘Usepopinfo’ = 0 for all individuals (n = 103). Each vertical bar represents the membership coefficient (<i>q</i>) for each individual. The final eight bars on the right represent hybrids from Estonia (Ehy 1–6) and Latvia (Lhy 1–2).</p

Median joining network of maternal lineages, based on mtDNA control region sequences (1134 bp), showing wolves, dogs and wolf-dog hybrids.

<p>Colours: green – dogs, blue – wolves, red – hybrids. W – wolf, D – dog, Ehy (1–6) – six hybrids from Estonia, Lhy (1–2) – two hybrids from Latvia. Numbers of individuals are in parentheses (if more than one individual is represented by the haplotype). Filled circles represent median vectors (haplotypes not sampled or extinct). Short bars indicate single mutations; otherwise the number of mutations is presented (note that the number of mutations and the length of bars are not in proportion).</p

First-generation (F1) wolf-dog hybrids from Wildlife Park Kadzidlowo, Poland: female wolf×male Polish Spaniel (left); female wolf×West Siberian Laika (right) (photos: A. Krzywinski).

<p>First-generation (F1) wolf-dog hybrids from Wildlife Park Kadzidlowo, Poland: female wolf×male Polish Spaniel (left); female wolf×West Siberian Laika (right) (photos: A. Krzywinski).</p

Bayesian phylogenetic tree of wolves, dogs and wolf-dog hybrids (from this study and homologous sequences from GenBank) based on the analysis of mtDNA control region sequences (1134 bp).

<p>Nodes with posterior probability values ≥0.80 are shown. Colours: green – dogs, blue – wolves, red – hybrids. Haplotypes representing more than one individual are numbered (circles 1–15). More detailed information about different haplotypes can be found in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0046465#pone.0046465.s004" target="_blank">Table S3</a>.</p

Filial generation status of wolf-dog hybrids from Estonia and Latvia, estimated with Structure v2.2 under different combinations of ‘Usepopinfo’ parameter settings.

<p>Parameter set – two different ‘Usepopoinfo’ parameter sets (A, B) applied to the same data (n = 103). 0 – ‘Usepopinfo’ set to 0; 1 - ‘Usepopinfo’ set to 1; Ehy – hybrids from Estonia (n = 6); Lhy – hybrids from Latvia (n = 2). The q values (membership coefficient) indicate the probability of individual genotypes to belong to wolf cluster (in parentehesis 90% credible regions).</p

Median joining network of paternal lineages, based on analysis of seven Y chromosome microsatellite loci, showing male wolves, dogs and wolf-dog hybrids.

<p>Colours: green – dogs, blue – wolves, red – hybrids. W – wolf, D – dog, Ehy – hybrids from Estonia.</p