Population Genetics in Marine Organisms

Population genetics in marine organisms investigates how genetic diversity is generated, maintained and redistributed across the world’s oceans. Unlike terrestrial systems, many marine species exhibit high dispersal capabilities via planktonic larvae or free-swimming adults, yet physical barriers such as currents, temperature gradients and biogeographic breaks can restrict gene flow and produce sharp genetic discontinuities. Processes of genetic drift, natural selection and historical demographic events interact to shape both neutral and adaptive variation. The advent of high-throughput sequencing and multilocus genotyping has revolutionised our capacity to resolve fine-scale population structure, reveal cryptic lineages and detect signatures of local adaptation. These insights are critical for defining management units, guiding conservation of threatened stocks and sustaining aquaculture industries through an understanding of connectivity and evolutionary resilience to environmental change.

Research from Nature Portfolio

Recent studies have harnessed genome-wide data to elucidate connectivity in aquaculture and wild fisheries. In a key mussel species, a combination of biophysical dispersal modelling and population genomic analyses pinpointed primary settlement areas and source beds, revealing that spat harvested for industry predominantly originate from adjacent mussel populations. This finding underpins targeted protection of source habitats to secure future spat supply. At a global scale, high-resolution single nucleotide polymorphism surveys of a major pelagic fish have overturned assumptions of panmixia by identifying discrete genetic stocks among ocean basins. Divergence at both neutral and candidate adaptive loci underscores the need to integrate evolutionary units into stock assessment and to tailor management measures that reflect both demographic connectivity and adaptive differences.

Population Genetics in Marine Organisms publication trend

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

Technical terms

Gene flow: The transfer of genetic material between populations through the movement of individuals, larvae or gametes.

Population structure: The organisation of genetic variation into subgroups within a species, often arising from limited dispersal or local adaptation.

SNP (Single Nucleotide Polymorphism): A single base-pair difference in DNA sequence among individuals, widely used as a genetic marker.

FST: A measure of genetic differentiation among populations, indicating the proportion of total genetic variance that lies between groups.

Biophysical model: A simulation that combines oceanographic currents and organismal life-history traits to predict larval or propagule dispersal pathways.

References

1. Range-wide population genomics of common seadragons shows secondary contact over a former barrier and insights on illegal capture. BMC Biology (2023).
2. Identifying the source populations supplying a vital economic marine species for the New Zealand aquaculture industry. Scientific Reports (2023).
3. Mitochondrial cytochrome c oxidase subunit I gene analysis of the yellowfin snapper, Lutjanus xanthopinnis in the Indo-Pacific region and a note on Lutjanus lutjanus population structure. Heliyon (2023).
4. The population genomics of yellowfin tuna (Thunnus albacares) at global geographic scale challenges current stock delineation. Scientific Reports (2018).