DOI: 10.5061/dryad.g4f4qrfvt
title: Nereocystis luetkeana microsatellite data (Genepop format)

description: In temperate regions, one of the most critical determinants of present
 range-wide genetic diversity was the Pleistocene climate oscillations, the
 most recent one created by the last glacial maximum (LGM). This study
 aimed to describe Nereocystis luetkeana genetic structure across
 its entire range (Alaska to California) and test different models of
 population connectivity within the Salish Sea. This region was colonized
 after the LGM and has been under increased disturbance in recent decades.
 We utilized microsatellite markers to study N.
 luetkeana genetic diversity at 53 sites across its
 range. Using higher sampling density in the Salish Sea, we employed a
 seascape genetics approach and tested isolation by hydrodynamic transport
 and environment models. At the species distribution scale, we found four
 main groups of genetic co-ancestry, Alaska; Washington with Vancouver
 Island's outer coast and Juan de Fuca Strait; Washington's inner
 Salish Sea; and Oregon with California. The highest allelic richness (AR)
 levels were found in California, near the trailing range edge, although AR
 was also high in Alaska. The inner Salish Sea region had the poorest
 diversity across the species distribution. Nevertheless, a pattern of
 isolation by hydrodynamic transport and environment was supported in this
 region. The levels of allelic richness and genetic differentiation suggest
 that during the LGM, bull kelp had both northern and southern glacial
 refugia in Haida Gwaii and Central California, respectively. Genetic
 diversity in Northern California sites seems resilient to recent
 disturbances, whereas the low levels of genetic diversity in the inner
 Salish Sea are concerning.
description: Sampling natural populations
 We sampled fifty-three sites across the
 geographic range of <em>N. luetkeana</em>, ranging from
 Herring Island, Alaska (59.65°N, 151.59°W) to Cambria Bay, California
 (35.53°N, 121.09°W), from May 2016 to August 2017. We collected a higher
 sampling site density inside the Salish Sea, the inner water body composed
 of the Strait of Georgia in British Columbia, Canada, and Puget Sound in
 Washington, USA (Figure 1, Table 1). Within each site, the average number
 of specimens collected was 40, ranging from 7 to 51. We sampled specimens
 haphazardly, separated by at least 2 meters, by cutting 2-4 cm pieces of
 blade tissue in a non-destructive manner. We wiped the sampled blade
 tissue to remove epiphytes before storing the tissue in silica gel
 desiccant for preservation until DNA extraction. Next, we used a Tissue
 Lyser II (Qiagen, Valencia, CA) to homogenize the silica-dried tissue to a
 fine powder before extracting DNA using the DNeasy Nucleospin 96 Plant Kit
 II (Machery-Nagel, Duren, Germany) following the kit protocol.
 Microsatellite loci genotyping
 We characterized microsatellite regions
 for <em>N. luetkeana</em> and used seven of the resulting
 microsatellite loci (Ner-2, Ner-4, Ner-6, Ner-9, Ner-11, Ner-13, and
 Ner-14, see article online supplementary material). We prepared PCRs in a
 total reaction volume of 15 µL comprised of 10 µM primer, 10 mM
 dNTP's per base (Promega, Madison, WI), 25 mM MgCl2, 3.0 µl 5X PCR
 buffer, and 0.5 U GoTaq Polymerase. Thermocycler conditions consisted of a
 5-minute denaturation step at 95ºC, followed by 33 cycles of 20 seconds
 each at 95ºC, 20 seconds at an annealing temperature of 57ºC–61ºC, 30
 seconds at 72ºC followed by a final elongation step of 20 minutes at 72ºC
 using an Eppendorf thermocycler
 (Eppendorf, USA). We sized microsatellite PCR fragments using
 fragment analysis on a 96-capillary DNA sequencer ABI 3730xl at the
 Madison Biotechnologies Center. We scored the resulting microsatellite
 fragments with STRand (https://www.vgl.ucdavis.edu/informatics/strand.php) and binned them into integer allele codes with the R (R Core Team, 2016) package “MsatAllele” (Alberto, 2009). The presence of null alleles was evaluated with MICRO-CHECKER v.2.2.3 (Van Oosterhout et al., 2004).
description: The format of the data is Genepop version 4.2 (Rousset, 2008)
 with 3 digits per allele. 
description: # Nereocystis luetkeana, the bull kelp, microsatellite data across the
 species range ## Description of the data and file structure The data
 format is that of genepop. Loci names are given in the same order as they
 appear in the columns below. Each specimen collected has its multi-locus
 genotype recorded in a single line. Different sampled populations are
 indicated in the first columns, Data from different populations is
 separated by a line with the single word Pop written. For more details on
 data format consult Genepop (Rousset, 2008) manual.