DOI: 10.5061/dryad.mq122fv
title: Data from: Parallel pattern of differentiation at a genomic island shared between clinal and mosaic hybrid zones in a complex of cryptic seahorse lineages

description: Diverging semi-isolated lineages either meet in narrow clinal hybrid
 zones, or have a mosaic distribution associated with environmental
 variation. Intrinsic reproductive isolation is often emphasized in the
 former and local adaptation in the latter, although both can contribute to
 isolation. Rarely these two patterns of spatial distribution are reported
 in the same study system. Here we report that the long-snouted seahorse
 Hippocampus guttulatus is subdivided into discrete panmictic entities by
 both types of hybrid zones. Along the European Atlantic coasts, a northern
 and a southern lineage meet in the southwest of France where they coexist
 in sympatry with little hybridization. In the Mediterranean Sea, two
 lineages have a mosaic distribution, associated with lagoon-like and
 marine habitats. A fifth lineage was identified in the Black Sea. Genetic
 homogeneity over large spatial scales contrasts with isolation maintained
 in sympatry or close parapatry at a fine scale. A high variation in
 locus-specific introgression rates provides additional evidence that
 partial reproductive isolation must be maintaining the divergence.
 Surprisingly, fixed differences between lagoon and marine populations in
 the Mediterranean Sea belong to the most differentiated SNPs between the
 two Atlantic lineages, against the genome-wide pattern of structure. These
 parallel outlier SNPs cluster on a single chromosome-wide island of
 differentiation. Since Atlantic lineages do not match the lagoon-sea
 habitat variation, genetic parallelism at the genomic island suggests a
 shared genetic barrier contributes to reproductive isolation in
 contrasting contexts -i.e. spatial vs. ecological. We discuss how a
 genomic hotspot of parallel differentiation could have evolved and become
 associated either with space or with a patchy environment in a single
 study system. Recommended in Yaniv Brandvain (2018) Genomic parallelism in
 adaptation to orthogonal environments in sea horses. Peer Community in
 Evolutionary Biology, 100056. doi:10.24072/pci.evolbiol.100056
description: Riquet_PCIEvolBiol_2018_INFILEArchived data - from Florentine Riquet, Cathy Liautard-Haag, Lucy Woodall, Carmen Bouza, Patrick Louisy, Bojan Hamer, Francisco Otero-Ferrer, Philippe Aublanc, Vickie Béduneau, Olivier Briard, Tahani El Ayari, Sandra Hochscheid, Khalid Belkhir, Sophie Arnaud-Haond, Pierre-Alexandre Gagnaire, Nicolas Bierne, - for "Parallel pattern of differentiation at a genomic island shared between clinal and mosaic hybrid zones in a complex of cryptic seahorse lineages", - and recommended by Peer Community In Evolutionary Biology (https://dx.doi.org/10.24072/pci.evolbiol.100056). The file is in excel format containing SNP data for all individuals analyzed. Columns are headed as follow: sampling location, the individual code followed by the 286 balletic SNPs (one column for one locus and each allele is coded in 1-digit). Contact: Florentine RIQUET Institut des Sciences de l’Evolution de Montpellier Université Montpellier Montpellier, France flo.riquet@gmail.com