Micro geographical population structure of cod Gadus morhua in the North Sea and west of Scotland: the role of sampling loci and individuals

Einar Eg Nielsen, Peter John Wright, Jakob Hemmer Hansen, Nina Aagaard Poulsen, Lain Monroe Gibb, Dorte Meldrup

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We investigated potential microgeographical population structure among spatial and temporal samples of cod Gadus morhua L., collected in the northern North Sea and around Scotland, using microsatellite genetic markers. Results were highly dependent on the samples and microsatellite loci included. Analysis of molecular variance (AMOVA) revealed significant spatial (p = 0.04) and temporal (p = 0.02) variance when including samples of juveniles and the microsatellite Gmo 132, which is known to be subject to selection. However, neither spatial nor temporal variance components were significant (p = 0.15 and 0.23, respectively) after exclusion of juvenile samples and Gmo 132. Patterns of genetic differentiation showed a similar sensitivity to the sampling of loci. No apparent pattern was identified when only using suspected neutral microsatellites. In contrast, analysis of Gmo132 alone revealed a clear isolation of 2 samples collected at Viking and pairwise grouping of temporal adult samples from the same location. On a northeast Atlantic regional scale, inferences on local populations and patterns of population structuring were more robust to the inclusion of the microsatellite under selection. Our results demonstrate that, without cautious consideration of biased samples of individuals and loci, apparent microgeographical patterns of spatial genetic differentiation could be caused by sampling non-randomly distributed individuals of hitch-hiking selection at presumed neutral marker loci. However, while loci subject to selection may provide biased results in relation to identifying populations based on an evolutionary paradigm, they may prove valuable for separating populations on ecological time scales
Original languageEnglish
JournalMarine Ecology Progress Series
Volume376
Pages (from-to)213-225
ISSN0171-8630
DOIs
Publication statusPublished - 2009

Cite this

@article{13ec7be363e845afafcc79df6fdf67e1,
title = "Micro geographical population structure of cod Gadus morhua in the North Sea and west of Scotland: the role of sampling loci and individuals",
abstract = "We investigated potential microgeographical population structure among spatial and temporal samples of cod Gadus morhua L., collected in the northern North Sea and around Scotland, using microsatellite genetic markers. Results were highly dependent on the samples and microsatellite loci included. Analysis of molecular variance (AMOVA) revealed significant spatial (p = 0.04) and temporal (p = 0.02) variance when including samples of juveniles and the microsatellite Gmo 132, which is known to be subject to selection. However, neither spatial nor temporal variance components were significant (p = 0.15 and 0.23, respectively) after exclusion of juvenile samples and Gmo 132. Patterns of genetic differentiation showed a similar sensitivity to the sampling of loci. No apparent pattern was identified when only using suspected neutral microsatellites. In contrast, analysis of Gmo132 alone revealed a clear isolation of 2 samples collected at Viking and pairwise grouping of temporal adult samples from the same location. On a northeast Atlantic regional scale, inferences on local populations and patterns of population structuring were more robust to the inclusion of the microsatellite under selection. Our results demonstrate that, without cautious consideration of biased samples of individuals and loci, apparent microgeographical patterns of spatial genetic differentiation could be caused by sampling non-randomly distributed individuals of hitch-hiking selection at presumed neutral marker loci. However, while loci subject to selection may provide biased results in relation to identifying populations based on an evolutionary paradigm, they may prove valuable for separating populations on ecological time scales",
author = "{Eg Nielsen}, Einar and Wright, {Peter John} and Hansen, {Jakob Hemmer} and Poulsen, {Nina Aagaard} and Gibb, {Lain Monroe} and Dorte Meldrup",
year = "2009",
doi = "10.3354/meps07798",
language = "English",
volume = "376",
pages = "213--225",
journal = "Marine Ecology - Progress Series",
issn = "0171-8630",
publisher = "Inter Research",

}

Micro geographical population structure of cod Gadus morhua in the North Sea and west of Scotland: the role of sampling loci and individuals. / Eg Nielsen, Einar; Wright, Peter John; Hansen, Jakob Hemmer; Poulsen, Nina Aagaard; Gibb, Lain Monroe; Meldrup, Dorte.

In: Marine Ecology Progress Series, Vol. 376, 2009, p. 213-225.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Micro geographical population structure of cod Gadus morhua in the North Sea and west of Scotland: the role of sampling loci and individuals

AU - Eg Nielsen, Einar

AU - Wright, Peter John

AU - Hansen, Jakob Hemmer

AU - Poulsen, Nina Aagaard

AU - Gibb, Lain Monroe

AU - Meldrup, Dorte

PY - 2009

Y1 - 2009

N2 - We investigated potential microgeographical population structure among spatial and temporal samples of cod Gadus morhua L., collected in the northern North Sea and around Scotland, using microsatellite genetic markers. Results were highly dependent on the samples and microsatellite loci included. Analysis of molecular variance (AMOVA) revealed significant spatial (p = 0.04) and temporal (p = 0.02) variance when including samples of juveniles and the microsatellite Gmo 132, which is known to be subject to selection. However, neither spatial nor temporal variance components were significant (p = 0.15 and 0.23, respectively) after exclusion of juvenile samples and Gmo 132. Patterns of genetic differentiation showed a similar sensitivity to the sampling of loci. No apparent pattern was identified when only using suspected neutral microsatellites. In contrast, analysis of Gmo132 alone revealed a clear isolation of 2 samples collected at Viking and pairwise grouping of temporal adult samples from the same location. On a northeast Atlantic regional scale, inferences on local populations and patterns of population structuring were more robust to the inclusion of the microsatellite under selection. Our results demonstrate that, without cautious consideration of biased samples of individuals and loci, apparent microgeographical patterns of spatial genetic differentiation could be caused by sampling non-randomly distributed individuals of hitch-hiking selection at presumed neutral marker loci. However, while loci subject to selection may provide biased results in relation to identifying populations based on an evolutionary paradigm, they may prove valuable for separating populations on ecological time scales

AB - We investigated potential microgeographical population structure among spatial and temporal samples of cod Gadus morhua L., collected in the northern North Sea and around Scotland, using microsatellite genetic markers. Results were highly dependent on the samples and microsatellite loci included. Analysis of molecular variance (AMOVA) revealed significant spatial (p = 0.04) and temporal (p = 0.02) variance when including samples of juveniles and the microsatellite Gmo 132, which is known to be subject to selection. However, neither spatial nor temporal variance components were significant (p = 0.15 and 0.23, respectively) after exclusion of juvenile samples and Gmo 132. Patterns of genetic differentiation showed a similar sensitivity to the sampling of loci. No apparent pattern was identified when only using suspected neutral microsatellites. In contrast, analysis of Gmo132 alone revealed a clear isolation of 2 samples collected at Viking and pairwise grouping of temporal adult samples from the same location. On a northeast Atlantic regional scale, inferences on local populations and patterns of population structuring were more robust to the inclusion of the microsatellite under selection. Our results demonstrate that, without cautious consideration of biased samples of individuals and loci, apparent microgeographical patterns of spatial genetic differentiation could be caused by sampling non-randomly distributed individuals of hitch-hiking selection at presumed neutral marker loci. However, while loci subject to selection may provide biased results in relation to identifying populations based on an evolutionary paradigm, they may prove valuable for separating populations on ecological time scales

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DO - 10.3354/meps07798

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VL - 376

SP - 213

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JF - Marine Ecology - Progress Series

SN - 0171-8630

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