Evolutionary Genetics of Marine Invertebrates

Marine invertebrates encompass a vast array of phyla that have colonised nearly every aquatic habitat, offering unique systems to dissect the genetic underpinnings of adaptation, speciation and resilience to environmental change. Evolutionary genetics in these taxa leverages high-throughput sequencing, population genomic surveys and comparative phylogenetics to characterise how selective forces shape key reproductive proteins, developmental pathways and stress-response systems. Broadcast-spawning species such as sea urchins, sea stars and bivalves have illuminated the role of gamete recognition molecules in driving species-specific fertilisation and prezygotic isolation, while studies of copepods and cnidarians reveal how balancing selection and local adaptation maintain genetic diversity across environmental gradients. The interplay of purifying and positive selection, coupled with gene flow and historical vicariance, underlies patterns of divergence from intertidal rock pools to abyssal ecosystems. Insights from these systems not only advance fundamental evolutionary theory but also inform conservation strategies for keystone invertebrates threatened by climate change, invasive species and habitat degradation, highlighting the imperative to integrate genetic data into marine resource management.

Research from Nature Portfolio

Recent molecular evolution studies have applied codon-based models and whole-genome sequencing to gamete recognition proteins in sea urchins. In Diadema species, bindin sequences exhibit strong purifying selection across most lineages, conserving the core motifs responsible for sperm–egg adhesion and membrane fusion. Genome-wide scans further reveal that only lineages in sympatry show episodic positive selection in bindin domains, suggesting adaptive divergence to minimise maladaptive hybridisation. These findings demonstrate how differential selective regimes on a single reproductive protein can drive both conservation and innovation, providing a molecular perspective on speciation in broadcast-spawning invertebrates.

Evolutionary Genetics of Marine Invertebrates publication trend

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

Technical terms

Purifying selection: Selective removal of deleterious alleles, leading to conservation of existing gene function.

Positive selection: Adaptive fixation of beneficial mutations, driving rapid divergence of functional regions.

Gamete recognition protein: Molecule on sperm or egg surface that mediates species-specific fertilisation.

Introgression: Incorporation of genetic material from one species or population into another via hybridisation and backcrossing.

Vicariance: Division of populations by geographic or environmental barriers, promoting independent evolutionary trajectories.

Broadcast spawning: Reproductive strategy in which organisms release gametes into the water column for external fertilisation.

References

1. Slow evolution under purifying selection in the gamete recognition protein bindin of the sea urchin Diadema. Scientific Reports (2020).
2. Membrane Fusion Is Induced by a Distinct Peptide Sequence of the Sea Urchin Fertilization Protein Bindin*. Journal of Biological Chemistry (1998).
3. Diversifying Selection Underlies the Origin of Allozyme Polymorphism at the Phosphoglucose Isomerase Locus in Tigriopus californicus. PLOS ONE (2012).
4. Extensive introgression among strongylocentrotid sea urchins revealed by phylogenomics. Ecology and Evolution (2023).
5. Trans-Arctic vicariance in Strongylocentrotus sea urchins. PeerJ (2022).