Gene flow governs the contemporary spatial structure and dynamic of populations as well as their long-term evolution. For species dispersing through atmospheric or oceanic flows, biophysical models allow predicting the migratory component of gene flow, which facilitates the interpretation of broad-scale structure inferred from allele frequencies among populations. However, frequent mismatches between dispersal estimates and observed genetic diversity prevent an operational synthesis for eco-evolutionary projections. Here we use an extensive compilation of 58 population genetic studies of 47 phylogenetically divergent marine sedentary species over the Mediterranean basin to assess how genetic differentiation is predicted by Isolation-By-Distance, single-generation and multigenerational dispersal models. The latter estimate random-walk connectivity probabilities across any numbers of steps in a generic temporal, directed, and weighted network characterizing ocean transport. They unveil explicit parents-to-offspring links (filial or explicit connectivity, realized by causal paths) and links among siblings from a common ancestor (coalescent or implicit connectivity, related to pitchfork motifs). We find that almost 70 % of observed variance in genetic differentiation is explained by coalescent connectivity over multiple generations, significantly outperforming other models. Our results bring novel insights into how ocean currents drive seascape connectivity and allow untangling the forces that shape population structure as well as anticipating climate-driven redistributions.  

Primary Presenter: Vincent Rossi, CNRS (vincent.rossi.ocean@gmail.com)

Authors:

Térence Legrand, Centro de Ciências do Mar (CCMAR)  (telegrand@ualg.pt)

Enrico Ser-Giacomi, Massachusetts Institute of Technology  (enricosg@mit.edu)

Ismael Hernández-Carrasco, Mediterranean Institute for Advanced Studies (UIB-CSIC)  (ihernandez@imedea.uib-csic.es)

Anne Chenuil, CNRS Aix Marseille Université IMBE  (anne.chenuil@imbe.fr)

Sophie Arnaud-Haond, Ifremer  (sarnaud@ifremer.fr)

Nicolas Bierne, ISEM – CNRS  (nicolas.bierne@umontpellier.fr)

Vincent Rossi, CNRS  (vincent.rossi.ocean@gmail.com)