11 research outputs found
Role of oceanography in shaping the genetic structure in the North Pacific hake <i>Merluccius productus</i>
<div><p>Determining the relative influence of biotic and abiotic factors on genetic connectivity among populations remains a major challenge in evolutionary biology and in the management and conservation of species. North Pacific hake (<i>Merluccius productus</i>) inhabits upwelling regions in the California Current ecosystem from the Gulf of California to the Gulf of Alaska. In this study, we examined mitochondrial DNA (mtDNA) and microsatellite variation to estimate levels of genetic differentiation of <i>M</i>. <i>productus</i> in relation to the role of oceanographic features as potential barriers to gene flow. Samples were obtained from nine sites spanning a large part of the geographic range of the species, from Puget Sound, Washington to Costa Rica. The microsatellite results revealed three genetically discrete populations: one spanning the eastern Pacific coast, and two apparently resident populations circumscribed to the Puget Sound and the northern Gulf of California (F<sub>ST</sub> = 0.032, p = 0.036). Cytochrome b sequence data indicated that isolation between the Puget Sound and northern Gulf of California populations from the coastal Pacific were recent phenomena (18.5 kyr for Puget Sound and 40 kyr for the northern Gulf of California). Oceanographic data obtained from the Gulf of California support the hypothesis that permanent fronts within the region, and strong gradients at the entrance to the Gulf of California act as barriers to gene flow. A seascape genetics approach found significant genetic–environment associations, where the daytime sea surface temperature and chlorophyll concentrations were the best predictive variables for the observed genetic differentiation. Considering the potential causes of genetic isolation among the three populations, e.g. spawning areas in different latitudes associated with upwelling processes, oceanographic barriers, asymmetric migration and specialized diet, oceanographic barriers appear to be a likely mechanism restricting gene flow.</p></div
Relaxed Bayesian topology with the estimated divergence times based on CYTB sequences for populations of <i>Merluccius productus</i> obtained with BEAST [65].
<p>Numbers at nodes indicate divergence time in millions of years. Blue bars correspond to the 95% highest posterior density (HPD) intervals. For clarity, samples from the NGC, PC and PS were collapsed into triangles.</p
Hierarchical analysis of molecular variance (AMOVA) of genetic variation of <i>Merluccius productus</i> for mitochondrial DNA (mtDNA) and microsatellite loci (M).
<p>Hierarchical analysis of molecular variance (AMOVA) of genetic variation of <i>Merluccius productus</i> for mitochondrial DNA (mtDNA) and microsatellite loci (M).</p
Redundancy analysis (RDA) for the association of oceanographic variables obtained from Ocean Color Web, and the ancestry coefficients of the three populations.
<p>Puget Sound (PS), Pacific Coast (PC) and Northern Gulf of California (NGC) generated in STRUCTURE. Chlorophyll <i>a</i> concentration (CHL) and sea day time surface temperature (SSTd).</p
Satellite and hydrographic data.
<p>Climatology of February of the Gulf of California (2002–2010) from the MODIS-Aqua satellites: sea surface temperature (SST) °C. Midriff archipelago region (MAR), northern Gulf of California (NGC), south of the Gulf of California (SGC), and entrance of Gulf of California (EGC).</p
Temperature and salinity profiles.
<p>(a) and (c) depict temperature and salinity distributions across the front located south of the Midriff Archipelago Region (MAR). (b) and (d) depict temperature and salinity distributions across the entrance of the Gulf of California.</p
Parameters of the mismatch distribution and neutrality test (Tajima’s <i>D</i>, Fu’s <i>Fs</i>) for populations of <i>Merluccius productus</i> based on mtDNA data.
<p>Parameters of the mismatch distribution and neutrality test (Tajima’s <i>D</i>, Fu’s <i>Fs</i>) for populations of <i>Merluccius productus</i> based on mtDNA data.</p
Pairwise F<sub><i>ST</i></sub> values (below diagonal) and ϕ<sub><i>ST</i></sub> (above diagonal) for <i>Merluccius productus</i>.
<p>Location abbreviations as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0194646#pone.0194646.t001" target="_blank">Table 1</a>.</p
Role of oceanography in shaping the genetic structure in the North Pacific hake <i>Merluccius productus</i> - Fig 4
<p><b>Genetic barriers detected using pairwise population differentiation indices for <i>Merluccius productus</i>: a) mtDNA and b) microsatellite data.</b> Red lines indicate genetic barriers. Voronoï tessellation shown in blue and the corresponding Delaunay triangulation of samples in green. Numbers in parentheses indicate bootstrap percentages. Abbreviations are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0194646#pone.0194646.t001" target="_blank">Table 1</a>.</p
Indices of genetic diversity from mtDNA sequences and microsatellite loci for <i>Merluccius productus</i>.
<p>Indices of genetic diversity from mtDNA sequences and microsatellite loci for <i>Merluccius productus</i>.</p