DOI: 10.5061/dryad.t1g1jwtgj
title: Data from: Population genomics and connectivity of the blue mussel species complex: Insights from a North-east Atlantic hybrid zone

description: Blue mussels (Mytilus spp.) are ecologically and economically important
 bivalves widespread in both hemispheres. Their relevance to coastal
 ecosystems and the aquaculture industry has made them extensively studied.
 The Mytilus complex consists of distinct genetic lineages, including
 Mytilus edulis, Mytilus galloprovincialis, Mytilus trossulus, and their
 fertile hybrids. In overlapping areas, they create complex hybrid zones,
 which have been investigated along European coasts, employing multi-marker
 approaches. However, knowledge gaps still exist in the North-east Atlantic
 region, in the middle of their hybrid zone around the island of Ireland,
 regarding their genomic composition, population structure, and
 connectivity. This study addresses these gaps by genotyping 781
 individuals from 26 sites encompassing Ireland’s hybrid zone, including
 both wild and farmed stocks from varying environmental conditions. Using a
 selected panel of 72 SNP markers, we examined relationships among
 genotypic composition, genetic diversity, isolation by distance (IBD), and
 environmental variables to identify drivers of Mytilus genetic structure.
 Results confirmed two distinct genetic lineages and their hybrids, with a
 clear geographic pattern: the east coast of Ireland is dominated by pure
 M. edulis genotype populations, while the south, west, and north coasts
 exhibit varying degrees of admixture with M. galloprovincialis genotype.
 Pure M. galloprovincialis populations were identified at specific sites on
 the west and north coast. Sea current resistance and wave height were
 significant predictors for both genotype composition and genetic
 differentiation. This study corroborates previous findings and provides
 the first comprehensive investigation of Irish Mytilus spp. Population
 structure and connectivity using a multi-marker approach. The findings
 highlight the importance of understanding the Mytilus complex’s
 composition and population dynamics to inform sustainable aquaculture
 practices and monitor potential climate change-driven shifts in the
 North-east Atlantic region.
description: # Data from: Population genomics and connectivity of the blue mussel
 species complex: Insights from a North-east Atlantic hybrid zone Dataset
 DOI: [10.5061/dryad.t1g1jwtgj](https://doi.org/10.5061/dryad.t1g1jwtgj) ##
 Description of the data and file structure ### Files and variables ####
 File: Cariolato_et_al_2025_MytilusIrish_PopGenomics.txt This txt file
 contains the Genepop .GEN file format is used for the population genomics
 analyses performed in RStudio. For each individuals, each column encodes
 for the genotype of each SNP marker (following the order of the markers
 listed).  E.g. individual A1 has 300300 for SNP marker
 "108748_B", therefore homozygous for GG Finally, each population
 is separated by "pop" line. Populations and individuals codes
 are reported in the Table 1 of the manuscript. * List of SNPs markers name
 * List of individuals name separated by populations (i.e. "pop")
 and following the code of Table 1 * Genotype data encoded as in .GEN file
 for Genepop software/R package, in a three digit format * A: 100 * C: 200
 * G: 300 * T: 400 * No calls: 000 ## Code/software The txt file can be
 saved as .gen to transformed it in "genind" file and can be
 imported in RStudio using the function "read.genepop" of the
 RStudio package "adegenet". adegenet package info ## Access
 information Data was derived from the following sources: * SNPs markers
 were retrieved from previously published studies (as correctly reported in
 the manuscript) * Fraïsse et al.,
 2016; [https://doi.org/10.1111/mec.13299](https://doi.org/10.1111/mec.13299) * Hammel et al., 2021; [https://doi.org/10.1111/mec.16052](https://doi.org/10.1111/mec.16052) * Simon et al., 2018; [https://doi.org/10.1002/evl3.66](https://doi.org/10.1002/evl3.66) * Wilson et al., 2018; [https://doi.org/10.1371/journal.pone.0200654](https://doi.org/10.1371/journal.pone.0200654)