Population Genomics of Marine Species in the Mediterranean

Population genomics has transformed our understanding of genetic structure, connectivity and adaptation in marine species across the Mediterranean. High-throughput sequencing enables genome-wide surveys of single nucleotide polymorphisms (SNPs) to uncover patterns of differentiation shaped by larval dispersal, oceanographic barriers and local selection. The region’s complex bathymetry and circulation, marked by fronts such as the Siculo-Tunisian Strait and Ligurian–Provencal current, interact with life history traits to generate heterogeneous gene flow. Recent research has revealed cryptic population structure in taxa once considered panmictic, highlighting fine-scale barriers to larval transport and adaptive divergence in ecologically important species. Such insights inform conservation of habitat-forming organisms, design of marine protected areas and management of fisheries. Integrating seascape genomics with environmental data has identified candidate genomic regions under selection by variables such as salinity, temperature and depth. Yet challenges remain, including sampling across linear and nonlinear oceanographic features, distinguishing neutral processes from selection and inference of demographic history. The global significance of these studies lies in refining models of connectivity in a semi-enclosed basin, with implications for other marginal seas. By linking genome-wide datasets to environmental heterogeneity, population genomics in the Mediterranean is poised to guide ecosystem-based management, resilience assessments under climate change and preservation of genetic diversity.

Research from Nature Portfolio

One study applied genotyping-by-sequencing to an endemic wrasse across the Adriatic and Ionian seas, recovering over 4,000 SNPs. Results revealed two principal barriers to gene flow: one isolating an island archipelago in the north-west and another separating eastern from south-western populations. Both neutral and outlier loci implicated positive selection in shaping this fine-scale structure, underscoring the interplay of habitat fragmentation and local adaptation.

Population Genomics of Marine Species in the Mediterranean publication trend

The graph below shows the total number of articles in population genomics of marine species in the mediterranean across all publications each year (not limited to Nature Index journals).

Technical terms

Population genomics: The study of genome-wide genetic variation within and between populations to infer evolutionary processes.

Single nucleotide polymorphism (SNP): A variation at a single base position in the genome, used as a marker for genetic diversity and structure.

Gene flow: The movement of genes or alleles between populations, often via larval dispersal in marine organisms.

Outlier loci: Genomic regions showing patterns of variation that deviate from neutral expectations, indicating possible selection.

Seascape genomics: An approach combining spatial environmental data with genomic information to identify factors driving genetic differentiation.

References

1. Population genomics of an endemic Mediterranean fish: differentiation by fine scale dispersal and adaptation. Scientific Reports (2017).
2. Impact of life history traits on gene flow: A multispecies systematic review across oceanographic barriers in the Mediterranean Sea. PLOS ONE (2017).
3. Unravelling population genetic structure with mitochondrial DNA in a notional panmictic coastal crab species: sample size makes the difference. BMC Ecology and Evolution (2016).
4. Navigating the currents of seascape genomics: how spatial analyses can augment population genomic studies. Current Zoology (2016).