Rare, long-distance dispersal underpins genetic connectivity in the pink sea fan, Eunicella verrucosa

Characterising patterns of genetic connectivity in marine species is of critical importance given the anthropogenic pressures placed on the marine environment. For sessile species, population connectivity can be shaped by many processes, such as pelagic larval duration, oceanographic boundaries, and currents. This study combines restriction-site associated DNA sequencing (RADseq) and passive particle dispersal modelling to delineate patterns of population connectivity in the pink sea fan, Eunicella verrucosa, a temperate octocoral. Individuals were sampled from 20 sites covering most of the species’ northeast Atlantic range, and a site in the northwest Mediterranean Sea to inform on connectivity across the Atlantic-Mediterranean transition. Using 7,510 neutral SNPs, a geographic cline of genetic clusters was detected, partitioning into: Ireland, Britain, France, Spain (Atlantic), and Portugal and Spain (Mediterranean). Evidence of significant inbreeding was detected at all sites, a find..., Pink sea fan tissue samples (n = 285) were collected via SCUBA (under sampling license L/2019/00143 granted by the Marine Management Organisation) from depths ranging between 5 and 35 m between 2007-2019. In brief, apical 5 cm cuttings were removed from each sea fan colony underwater and preserved in >95% ethanol immediately after surfacing to prevent DNA degradation. Samples were stored long-term at 4 oC. Genomic DNA was extracted from polyp tissue using a salting-out protocol optimised for gorgonin-protein tissue (see Supplementary Material associated with the manuscript for full protocol).
Sequencing and SNP isolation were performed through nextRAD, a reduced representation sequencing method. Genomic DNA was first fragmented with Nextera reagent (Illumina, Inc), which also ligates short adapter sequences to the ends of the fragments. The Nextera reaction was scaled for fragmenting 5 ng of genomic DNA, although 7.5 ng of genomic DNA was used for input to compensate for degraded DNA..., , # **Rare, long-distance dispersal underpins genetic connectivity in the pink sea fan, *Eunicella verrucosa***

This repository contains relevant raw and filtered data, along with annotated R scripts to run the analyses within this manuscript (or adapt to your own datasets of the same format).

## Description of the data and file structure

1. Method Types and Data Generation

\--Next RADseq derived SNP data obtained from rangewide samples of pink sea fan (*Eunicella verrucosa*) colonies.

\--Passive particle tracking trajectories obtained using an Atlantic-Iberian Biscay Irish-Ocean Physics analysis and a Forecast oceanographic model from CMEMS in R.

\--Raw ASCI and NC files of marine environmental data obtained via BioOracle ([https://bio-oracle.org/) and](https://bio-oracle.org/) Copernicus () needed for Redundancy Analysis.

\--R scripts to run all major analyses within the manuscript to address questions of population structure, genetic diversity and differentiat...