show Abstracthide AbstractWe analysed Bathymodiolus mussel lineages from four geographic regions on the Mid-Atlantic Ridge. To investigate how their mitochondrial and nuclear genomes relate and whether we find subpopulation structure in conspecific mussels from different vent fields in the same region, we used exome-wide SNP profiling and assessed mitochondrial genomes of 175 mussel individuals sampled at 10 vent fields (including 22 sites).