Can ocean-current models explain how Caribbean coral populations are genetically connected?

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Understanding how populations of marine organisms are connected is essential for developing realistic models of population dynamics that explicitly represent space. Empirical genetic patterns and oceanographic dispersal modelling have both been used to estimate connectivity among marine populations over evolutionary timescales, but their potentially complementary insights have rarely been combined.

This study integrated a spatially realistic Lagrangian model of larval dispersal and a theoretical genetic model with what the abstract describes as the most extensive study of gene flow in a Caribbean marine organism. The empirical study concerned populations of the reef-building coral Montastraea annularis. Researchers collected 871 genets—genetically distinct individuals—from 26 sites across the wider Caribbean, sampling 45.8% of the 1900 potential unique genets in the model.

At a coarse spatial scale, modelled estimates of genetic structure and empirical genetic data showed significant agreement. However, modelled and empirical estimates of connectivity differed among northern Mesoamerican reefs, indicating that processes other than dispersal may dominate there.

The study also refined the geographic location and porosity—how permeable it is to gene flow—of the previously described east–west barrier to gene flow in the Caribbean. Overall, the combined approach, integrating genetic data with spatially realistic models of larval dispersal and genetic projection, provided complementary insights into the processes underlying connectivity among marine invertebrate populations over evolutionary timescales.