Gorgonia ventalina microsatellite genotype dataStructure formatG_ventalina_microsat_genotype_data.txtGeographic distance matrix by locality***README: This is a matrix of pairwise geographic distances between all sampling localities used in the manuscript entitled "Range-wide population genetic structure of the Caribbean sea fan coral, Gorgonia ventalina" by Andras JP, Rypien KL, & Harvell CD published in Molecular Ecology in 2012. The first row and first column contain locality numbers, which are in the same order as the localities in Table 1 of the corresponding manuscript. All other cells contain pairwise distances in kilometers. The matrix is symmetrical, meaning the values are identical across the diagonal. Please direct any questions regarding these data to Jason Andras at jpa24@cornell.edu.Geographic Distance Matrix by localityAverage annual dispersal probability by region***README: This is a matrix of pairwise dispersal probabiliteis between sampling regions used in the manuscript entitled "Range-wide population genetic structure of the Caribbean sea fan coral, Gorgonia ventalina" by Andras JP, Rypien KL, & Harvell CD, published in Molecular Ecology in 2012. The first first column contains the region name. The second column contains the localities averaged within that region (locality numbers correspond to Table 1 of the manuscript). Column three and the top row contain the numerical designation for each region. All other cells contain pairwise annual average dispersal probabilities between regions, given as [log(dispersal probability +1)]. The matrix is asymmetrical, meaning the values are not identical across the diagonal. To compare this matrix to measures of genetic distance, bidirectional dispersal probabilites can be averaged to generate a lower triangular matrix, or the asymmetric matrix below can be compared to a full-square symmetric matrix of genetic distances. Please direct any questions regarding these data to Jason Andras at jpa24@cornell.edu.Dispersal probability matrix by region

The population structure of benthic marine organisms is of central relevance for the conservation and management of these often threatened species as well as an accurate understanding of their ecological and evolutionary dynamics. A growing body of evidence suggests that marine populations can be structured over short distances despite theoretically high dispersal potential. Yet the proposed mechanisms governing this structure vary, and existing empirical population genetic evidence is of insufficient taxonomic and geographic scope to allow strong general inferences. Here we describe the range-wide population genetic structure of an ecologically important Caribbean octocoral, Gorgonia ventalina. Genetic differentiation was positively correlated with geographic distance and negatively correlated with oceanographically-modeled dispersal probability throughout the range. Although we observed admixture across hundreds of kilometers, estimated dispersal is low, and populations can be differentiated across distances <2km. These results suggest that populations of G. ventalina may be evolutionarily coupled via gene flow but are largely demographically independent. Observed patterns of differentiation corroborate biogeographic breaks identified in other taxa (e.g. an east/west divide near Puerto Rico) and also identify population divides not discussed in previous studies (e.g. the Yucatan Channel). Across the range, diversity was positively correlated with latitude, consistent with a source/sink dynamic driven by ocean currents. High genotypic diversity and absence of clonemates indicate that sex is the primary reproductive mode for G. ventalina. A comparative analysis of the population structure of G. ventalina and its dinoflagellate symbiont, Symbiodinium, indicates that the dispersal of these symbiotic partners is not coupled, and symbiont transmission occurs horizontally.