Mitochondrial cytochrome b DNA sequence variation of Atlantic cod Gadus morhua, from Norway

Authors

  • E. ARNASON,

    Corresponding author
    1. Institute of Biology, University of Iceland, Grensásvegur 12, 108 Reykjavik, Iceland
      Office: +354–525-4613. Lab: +354–525-4606. Fax: +354–525-4069. E-mail: einar@lif.hi.is
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  • S. PÁLSSON

    1. Institute of Biology, University of Iceland, Grensásvegur 12, 108 Reykjavik, Iceland
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    • *Program of Conservation Biology, Department of Genetics, University of Uppsala, Box 7003, 750 07 Uppsala, Sweden.


  • This paper on Norwegian cod is part of a larger project being carried out in Einar Arnason's laboratory of population genetics using DNA variation and neutral theory to study population structure and gene flow in fish, in particular cod of the eastern Atlantic. Snæbjörn Palsson worked on the project before starting his current PhD work.

Office: +354–525-4613. Lab: +354–525-4606. Fax: +354–525-4069. E-mail: einar@lif.hi.is

Abstract

We studied sequence variation of a fragment of the mitochondrial cytochrome b gene using polymerase chain reaction (PCR) and direct sequencing among 85 Norwegian Atlantic cod Gadus morhua, from nine sampling localities representing three overall areas: arctic, coastal and middle. In the analysis we include an additional 15 cod studied by Carr & Marshall (1991a). Nine base changes were found among the 100 sequences defining 11 haplotypes which differ from each other by one to five mutations. Two sites have been hit twice. All but one mutation are at third position silent sites. The variation passes several neutral-theory tests and is thus suitable as marker for studying population differentiation. Coefficients of coancestry or intraclass correlation coefficient are negative both at the level of individuals within localities and localities within areas. This implies greater differences among individuals within populations than between populations. Intralocality nucleotide diversity is high and masks interlocality nucleotide divergence such that the net interlocality nucleotide divergence is nil. Similarly the net interarea nucleotide divergence is nil.

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