DOI: 10.5061/dryad.xgxd254gw
title: Gradients of genetic diversity and differentiation across the distribution range of a Mediterranean coral: patterns, processes and conservation implications.

description: The aim of this study was to determine how historical and contemporary
 eco-evolutionary processes shape the patterns of genetic diversity and
 differentiation across species’ distribution range remains an open
 question with strong conservation implications. Focusing on the orange
 stony coral, Astroides calycularis, we i) characterized the
 pattern of neutral genetic diversity across the distribution range; ii)
 gave insights into the underlying processes; and iii) discussed
 conservation implications with emphasis on a national park located on a
 hotspot of genetic diversity. Location: South Mediterranean Sea
 and Zembra National Park. We combined new data from 12 microsatellites in
 13 populations located in the Centre and in the Western Periphery of the
 distribution range with a published dataset including 16 populations from
 the Western and Eastern Peripheries. We analysed the relationship among
 parameters of genetic diversity (He, Ar(g)) and structure
 (population-specific FST) and two measures of geographic
 peripherality. We compared two estimators of pairwise genetic structure
 (GST, DEST) across the distribution range. The evolutionary and
 demographic history of the populations following the Last Glacial Maximum
 was reconstructed using approximate Bayesian computations and Maximum
 Likelihood analyses. We inferred the contemporary connectivity among
 populations from Zembra National Park and with the neighbouring area of
 Cap Bon. We demonstrate a decrease of genetic diversity and an
 increase of genetic differentiation from the Centre to the Eastern and
 Western Peripheries of the distribution range. Populations from
 Zembra show the highest genetic diversity reported in the species. We
 identified a spillover effect towards Cap Bon. The patterns of
 genetic diversity and differentiation are most likely explained by “the
 postglacial range expansion hypothesis” rather than the
 “central-peripheral hypothesis”. Enforcement of conservation measures
 should be considered to protect this genetic diversity pattern, in
 particular when considering the low effective population size inferred at
 many sites.
description: The dataset is a genotyping dataset in Genepop format (see
 https://kimura.univ-montp2.fr/~rousset/Genepop4.7.pdf).<br> It is
 composed by the genotypes at 12 microsatellites of 655 individuals coming
 from 29 populations (see Table 1 in Ledoux et al. 2021, Diversity and
 Distributions for details).<br> The first line of the dataset
 corresponds to the title, the following 12 lines are the locus
 names.<br> Each line contains the name of the individual and the
 genotype at each of the 12 microsatellites.<br> The populations are
 delimited by a "pop" line.<br> Part of the data came from
 Casado-Amueza et al. 2012 (Molecular Ecology, 21, 3671-3685). The
 remaining samples were genotyped during the study (see Ledoux et al. 2021,
 Diversity and Distributions for details).
description: The standardization of the allele scoring between the two
 datasets (Casado-Amueza et al vs. Ledoux et al) is detailled in
 the Appendix 2 in Ledoux et al. 2021, Diversity and Distributions.
 Briefly, it is based on the comparison of allele frequencies in three
 populations (ALF, ALM and PC; Table 1, Figure 1), that were sampled in the
 same location among the two studies.  Missing genotypes
 are coded with "000000".