Biophysical simulations of western Atlantic Sargassum dispersal: Major ocean currents move in an eastward direction throughout the Gulf of Mexico into the Atlantic Ocean. Sargassum "rafts" (a common buoyant marine plant species) are utilized by many species of seahorses and pipefishes as a means of passive dispersal. Each figure is a snapshot taken every 1.5 months from March-November (2005). In collaboration with Nathan Putman.
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Below (genomic RADseq analyses): Coalescent model-based inference of five codistributed species from roughly 3,600-6,500 loci per species (Boehm et al. in preparation). J.T. Boehm evolution
Above: Demographic models were informed based on the number of ancestral gene pools, PCA, and maximum likelihood topologies. For an applied example of these methods see New York's seahorse: Population genomics
Four of the five species show asymmetrical post-divergence gene flow (Nm) between independent ancestral gene pools (i.e., populations) in the direction of major ocean currents.. In general, species with a higher rafting propensity exhibited elevated gene flow magnitudes (arrows scaled to Nm estimates). Other parameters from the models above such as divergence time, size change over time, and effective population sizes are not shown. The allele frequency spectrum (AFS) per species was calculated and analyzed using Fastsimcoal25 for coalescent simulation and composite likelihood parameter estimates..
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