Distance matrix for the MDS ordination

Pairwise interpopulation ΦST distance matrix of trans-Arctic lineage populations for MDS ordination

Arlq_cr_populations

Arlequin input files with population grouping for control region data

SampleID_list

List of individual samples with sampling locations and Genbank accession numbers for cytochrome-b and control region

IM_CYTB_NWP_MEZCHE

IM input file for comparing NW Pacific lineage with Mezen-Chesha populations

Arlq_cytb_populations

Arlequin input files with population grouping for cytochrome-b data

Arlq_trans_Arctic_populations_concat

Arlequin input files with population grouping for concatenated data

IM_CYTB_NWP_BLS

IM input file for comparing NW Pacific lineage with Balsfjord population

Map of study area and sampling sites.

<p>(A). Location of the Kandalaksha Bay of the White Sea, and general distribution of three mussel taxa in Europe: ME (<i>Mytilus edulis</i>, blue), MT (<i>M</i>. <i>trossulus</i>, red) and <i>M</i>. <i>galloprovincialis</i> (MG, yellow). Bi- or tri-colored circles indicate zones of sympatry (see references in the text). (B-D) Sampling locations in the White Sea: (B) Kandalaksha Bay. (C) Umba town area. (D) Top of Kandalaksha Bay. Pie diagrams depict estimates of the proportions of ME (blue sector) and MT (red sector) genomes in samples from the genetic dataset (GDS), obtained by STRUCTURE analysis of four-locus genotype data (PSS, see text for details). Data on paired local subsamples collected from the algal and the bottom substrates are shown above and below the algae pictogram, respectively. Black pins indicate sampling sites of the MDS (morphology only). Detailed sampling locality data are in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152963#pone.0152963.s004" target="_blank">S1 Table</a>. The green lines in part D are isohalines of surface water (after [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152963#pone.0152963.ref034" target="_blank">34</a>]).</p

Mussel morphotypes and their distribution between different genotypes, and between algal and bottom substrates.

<p>(A). Mussel shells of different morphotypes: T-morphotype with an unbroken prismatic dark strip under ligament (lower shell) and E-morphotypes with the dark strip broken (middle) or absent (upper shell). Measurements indicated: L–total shell length, l–distance from shell umbo to the posterior end of the ligament, a–distance from umbo to the anterior end of the dark strip. The index Z = a/l; values of Z corresponding to the different morphotypes are shown. (B). The kernel density function of Z-values within the three genotypic classes (all samples pooled, the genotypic classes defined on the basis of STRUCTURE analysis, see text for details). Yellow dots indicate the medians. (C). Mussels growing on different substrates: on bottom ground vs. fucoid thalli. (D). The mean frequencies of T-morphotype (Z = 0) ± standard error on the algae (horizontal axis) plotted against that on the bottom in samples from 17 sites of MDS. If frequencies were identical on both substrates, the dots would fall on the diagonal (black line).</p

Taxonomic composition and morphological features of putative purebred and hybrid mussels in samples of different genetic composition.

<p>PSS on abscissas are plotted against: (A). frequencies of ME (blue symbols), MT (red symbols) and hybrids (green symbols) in samples; (B). ratios between sample means of shell length L of MT and hybrids (red symbols) and ME and hybrids (blue symbols) in samples; (C). frequencies of T-morphotypes among ME (blue symbols), MT (red symbols) and hybrid (green symbols) genetic classes in samples. Polynomial (A) or linear (B, C) functions were fitted to the data. Groups of less than 4 genotypes are not included. Classification of genotypes to ancestry classes in all cases was ISS-based.</p