DOI: 10.5061/dryad.w6m905qkc
title: Genetic structures across a biogeographical barrier reflect dispersal potential of four Southeast Asian mangrove plant species

description: Aim Biogeographic barriers restrict the movement of individuals, resulting
 in population divergence, genetic differentiation, endemism and
 speciation. Yet, some barriers demonstrate unequal effect across species
 depending on species dispersal, which manifests in varying genetic
 structure. We test the hypotheses that the genetic structure of four
 coastal mangrove species would reflect differences in dispersal potential
 across the Malay Peninsula, a major biogeographic barrier in the Indo-West
 Pacific region. Location Twelve sites from the east and west coasts of the
 Malay Peninsula. Taxon Mangrove trees Avicennia alba, Sonneratia alba,
 Bruguiera gymnorhiza, and Rhizhophora mucronata. Methods For each species,
 we characterized genetic structure and gene flow using seven to 12
 species-specific nuclear microsatellite markers. We tested for east-west
 genetic differentiation across the peninsula, a stepping-stone migration
 pattern, and assessed the proportion of recent dispersal and direction of
 historical migration along the Malacca Strait. Results Significant
 east-west genetic differentiation across the peninsula was observed in A.
 alba, S. alba and B. gymnorhiza, and the effect was most pronounced for
 the two species with lower dispersal potential (A. alba, S. alba). In
 contrast, the two species with higher dispersal potential (B. gymnorhiza
 and R. mucronata) exhibited much higher proportion of recent
 inter-population migration along the Malacca Strait. The signature of
 historical colonization from refugia in the Andaman Sea (north-to-south
 migration along the Malacca Strait) predominated for A. alba and S. alba.
 Historical south-north migration predominated for R. mucronata and B.
 gymnorhiza. Main conclusions This study is the first to implicate
 dispersal potential as a causal factor of varying mangrove species genetic
 structure across a biogeographic barrier. The Malay Peninsula functions as
 a filter to gene flow rather than a barrier. The genetic structure in
 mangrove species with a higher dispersal potential is more congruent with
 contemporary gene flow while that of species with a lower dispersal
 potential reflects historical processes.Our findings hint at the role of
 dispersal potential as a predictor of gene flow in mangroves.
description: We sampled all species at the same twelve sites along the east
 and west coasts of the Malay Peninsula (<i>n</i> = 22-49
 individuals per species per locality). A leaf sample was collected from
 each individual, dried and stored using silica gel. Genomic DNA was
 extracted from leaf samples collected from each individual plant using a
 modified CTAB method (Doyle & Doyle, 1987). Species-specific
 nuclear microsatellite loci were then employed to genotype the samples in
 each species. Eight, eight, seven and 12 loci were employed for
 <i>A. alba</i>, <i>S. alba</i>, <i>B.
 gymnorhiza</i> and <i>R. mucronata</i>, respectively
 (see manuscript). All loci were genotyped using primers labelled with one
 of the four fluorescent dyes, 6-FAM, VIC, NED and PET. Amplified products
 were run on an ABI 3031xl automated sequencer (Applied Biosystems) with
 the GeneScan-600 LIZ size standard (Applied Biosystems) and analyzed using
 GeneMapper ®
 4.1 software (Applied Biosystems). 
description: We uploaded individual file for each species in GENEPOP format,
 named by the abbreviation of the species name (e.g. AA = Avicennia alba).
 Missing data was denoted by "0".