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Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus morhua L.).
Genome Biol Evol. 2015 May 20; 7(6):1644-63.GB

Abstract

How genomic selection enables species to adapt to divergent environments is a fundamental question in ecology and evolution. We investigated the genomic signatures of local adaptation in Atlantic cod (Gadus morhua L.) along a natural salinity gradient, ranging from 35‰ in the North Sea to 7‰ within the Baltic Sea. By utilizing a 12 K SNPchip, we simultaneously assessed neutral and adaptive genetic divergence across the Atlantic cod genome. Combining outlier analyses with a landscape genomic approach, we identified a set of directionally selected loci that are strongly correlated with habitat differences in salinity, oxygen, and temperature. Our results show that discrete regions within the Atlantic cod genome are subject to directional selection and associated with adaptation to the local environmental conditions in the Baltic- and the North Sea, indicating divergence hitchhiking and the presence of genomic islands of divergence. We report a suite of outlier single nucleotide polymorphisms within or closely located to genes associated with osmoregulation, as well as genes known to play important roles in the hydration and development of oocytes. These genes are likely to have key functions within a general osmoregulatory framework and are important for the survival of eggs and larvae, contributing to the buildup of reproductive isolation between the low-salinity adapted Baltic cod and the adjacent cod populations. Hence, our data suggest that adaptive responses to the environmental conditions in the Baltic Sea may contribute to a strong and effective reproductive barrier, and that Baltic cod can be viewed as an example of ongoing speciation.

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Authors+Show Affiliations

Berg PR
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway.
Jentoft S
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway.
Star B
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway.
Ring KH
Centre for Development and the Environment (SUM), University of Oslo, Norway.
Knutsen H
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway Institute of Marine Research (IMR), Flødevigen, His, Norway University of Agder, Kristiansand, Norway.
Lien S
Centre for Integrative Genetics (CIGENE), Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Aas, Norway.
Jakobsen KS
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway k.s.jakobsen@ibv.uio.no.
André C
Department of Biology and Environmental Sciences-Tjärnö, University of Gothenburg, Strömstad, Sweden.

MeSH

Adaptation, PhysiologicalAnimalsGadus morhuaGenesGenomeGenomicsLinkage DisequilibriumPolymorphism, Single NucleotideSalinitySelection, Genetic

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

25994933

Citation

Berg, Paul R., et al. "Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus Morhua L.)." Genome Biology and Evolution, vol. 7, no. 6, 2015, pp. 1644-63.
Berg PR, Jentoft S, Star B, et al. Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus morhua L.). Genome Biol Evol. 2015;7(6):1644-63.
Berg, P. R., Jentoft, S., Star, B., Ring, K. H., Knutsen, H., Lien, S., Jakobsen, K. S., & André, C. (2015). Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus morhua L.). Genome Biology and Evolution, 7(6), 1644-63. https://doi.org/10.1093/gbe/evv093
Berg PR, et al. Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus Morhua L.). Genome Biol Evol. 2015 May 20;7(6):1644-63. PubMed PMID: 25994933.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus morhua L.). AU - Berg,Paul R, AU - Jentoft,Sissel, AU - Star,Bastiaan, AU - Ring,Kristoffer H, AU - Knutsen,Halvor, AU - Lien,Sigbjørn, AU - Jakobsen,Kjetill S, AU - André,Carl, Y1 - 2015/05/20/ PY - 2015/5/22/entrez PY - 2015/5/23/pubmed PY - 2015/12/19/medline KW - Atlantic cod KW - Baltic Sea KW - SNPs KW - ecological divergence KW - genomic adaptation KW - population genomics KW - speciation SP - 1644 EP - 63 JF - Genome biology and evolution JO - Genome Biol Evol VL - 7 IS - 6 N2 - How genomic selection enables species to adapt to divergent environments is a fundamental question in ecology and evolution. We investigated the genomic signatures of local adaptation in Atlantic cod (Gadus morhua L.) along a natural salinity gradient, ranging from 35‰ in the North Sea to 7‰ within the Baltic Sea. By utilizing a 12 K SNPchip, we simultaneously assessed neutral and adaptive genetic divergence across the Atlantic cod genome. Combining outlier analyses with a landscape genomic approach, we identified a set of directionally selected loci that are strongly correlated with habitat differences in salinity, oxygen, and temperature. Our results show that discrete regions within the Atlantic cod genome are subject to directional selection and associated with adaptation to the local environmental conditions in the Baltic- and the North Sea, indicating divergence hitchhiking and the presence of genomic islands of divergence. We report a suite of outlier single nucleotide polymorphisms within or closely located to genes associated with osmoregulation, as well as genes known to play important roles in the hydration and development of oocytes. These genes are likely to have key functions within a general osmoregulatory framework and are important for the survival of eggs and larvae, contributing to the buildup of reproductive isolation between the low-salinity adapted Baltic cod and the adjacent cod populations. Hence, our data suggest that adaptive responses to the environmental conditions in the Baltic Sea may contribute to a strong and effective reproductive barrier, and that Baltic cod can be viewed as an example of ongoing speciation. SN - 1759-6653 UR - https://www.unboundmedicine.com/medline/citation/25994933/Adaptation_to_Low_Salinity_Promotes_Genomic_Divergence_in_Atlantic_Cod__Gadus_morhua_L___ DB - PRIME DP - Unbound Medicine ER -