DOI: 10.5061/dryad.0gb5mkkwm
title: Climate‐induced range shifts shaped the present and threaten the future genetic variability of a marine brown alga in the Northwest Pacific

description: Glaciation‐induced environmental changes during the last glacial maximum
 (LGM) have strongly influenced species' distributions and genetic
 diversity patterns in the northern high latitudes. However, these effects
 have seldom been assessed on sessile species in the Northwest Pacific.
 Herein, we chose the brown alga Sargassum thunbergii to test this
 hypothesis by comparing present population genetic variability with
 inferred geographical range shifts from the LGM to the present, estimated
 with species distribution modelling (SDM). Projections for contrasting
 scenarios of future climate change were also developed to anticipate
 genetic diversity losses at regional scales. Results showed that S.
 thunbergii harbours strikingly rich genetic diversity and multiple
 divergent lineages in the centre‐northern range of its distribution, in
 contrast with a poorer genetically distinct lineage in the southern range.
 SDM hindcasted refugial persistence in the southern range during the LGM,
 as well as post‐LGM expansion of 18 degrees of latitude northward.
 Approximate Bayesian computation (ABC) analysis further suggested that the
 multiple divergent lineages in the centre‐northern range limit stem from
 post‐LGM colonization from the southern surviving lineage. This suggests
 divergence due to demographic bottlenecks during range expansion and
 massive genetic diversity loss during post‐LGM contraction in the south.
 The projected future range of S. thunbergii highlights the threat to
 unique gene pools that might be lost under global changes.
description: # Climate‐induced range shifts shaped the present and threaten the future
 genetic variability of a marine brown alga in the Northwest Pacific
 Dataset DOI:
 [10.5061/dryad.0gb5mkkwm](https://doi.org/10.5061/dryad.0gb5mkkwm) ##
 Description of the data and file structure File:
 Fst_values_among_35_populations.xlsx File:
 Josts_D_matrix_among_35_populations.xlsx File: Occurrence_records.zip
 File: SSR_genotyping_datasets.xlsx ### Files and variables We have
 submitted four files: “Fst-values-among-35-poppulations.xlsx”,
 “Josts_D_matrix_among_35_populations.xlsx”, “Occurrence_records.zip”,
 “SSR_genotyping_datasets.xlsx” #### Description of the data file
 **Fst-values-among-35-poppulations.xlsx** \* Numbers 1-35 represent 35
 Sargassum thunbergii populations, including their sampling localities
 (site, city, country) respectively. \* The matrix is Fst estimates among
 35 S. thunbergii populations. **Josts_D_matrix_among_35_populations.xlsx**
 \* Numbers 1-35 represent 35 Sargassum thunbergii populations, including
 their sampling localities (site, city, country) respectively. \* The
 matrix is Josts_D estimates among 35 S. thunbergii populations.
 **Occurrence_records.zip** This is a compressed file fold in which there
 are three files. The file with names “Literature.Sargassum.thunbergii”,
 “Repository.Sargassum.thunbergii”, “Sargassum thunbergii”. \*
 “Literature.Sargassum.thunbergii”, this file included 9 scientific
 literatures with detailed publication information which were used to
 search for occurrence records of S. thunbergii. \*
 “Repository.Sargassum.thunbergii”, this file listed 4 online databases
 used to search for occurrence records of S. thunbergii. \* “Sargassum
 thunbergii”, this file contains detailed 357 occurrence records of S.
 thunbergii in the northwest Pacific after combining all referred
 occurrence histories together. **SSR_genotyping_datasets.xlsx** \* “npops”
 indicates the number of populations. \* “nloci” indicates the number of
 genetic locus amplified and used for genetic analysis. \* “pop” indicate
 population. \* The words such as “Muroran” in the first row indicate
 sampling localities. \* The words such as “JPMUROO1” or “CORGC001” in the
 first row indicate individuals in each population, respectively. \* The
 abbreviations such as “SW1” in the fourth column indicate the names of 11
 microsatellite (Simple sequence repeat). \* In the microsatellite dataset
 matrix, there are some symbols “?” appeared for some individuals amplified
 with certain loci, and this symbol “?” indicate NOT AVAILABLE. We kept
 this form to not disrupt genetic analysis when using specific statistical
 softwares. #### Access information Other publicly accessible locations of
 the data: * Not applicable Data was derived from the following sources: *
 Not applicable