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Population differentiation and evolution in the common guillemot Uria aalge

Authors

  • V. L. FRIESEN,

    Corresponding author
    1. *Biopsychology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X9, Canada
    2. †Department of Ornithology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada
      Tel.: + 1–613-5456156. Fax + 1–613-5456617. E-mail friesenv@biology.queensu.ca
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    • ‡Department of Biology, Queen's University, Kingston, Ontario K7 L 3N6, Canada.

  • W. A. MONTEVECCHI,

    1. *Biopsychology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X9, Canada
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  • A. J. BAKER,

    1. †Department of Ornithology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada
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  • R. T. BARRETT,

    1. §Tromse Museum, University of Tromse, N-9037 Tromse, Norway
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  • W. S. DAVIDSON

    1. ¶Department of Biochemistry, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X9, Canada
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  • This study was conducted as part of a doctoral research project by V.L.F.; she is continuing her investigations into mechanisms of population differentiation and speciation in birds as an Assistant Professor of Biology at Queen's University. W.A.M. is Head of the Biopsychology Program at Memorial University of Newfoundland and studies the ecology and behaviour of marine birds. A.J.B. is Director of the Biodiversity Centre and Curator of Ornithology at the Royal Ontario Museum, and studies the evolutionary genetics of vertebrates. R.T.B. is Museum Lecturer in Marine Biology at the Tromse Museum, and studies the breeding biology and ecology of seabirds. W.S.D. is Associate Dean of Science (Research) and an Associate Professor of Biochemistry at Memorial University of Newfoundland, and studies the molecular genetics of vertebrates.

Tel.: + 1–613-5456156. Fax + 1–613-5456617. E-mail friesenv@biology.queensu.ca

Abstract

Common (Uria aalge) and Brünnich's guillemots (U. Iomvia) are colonial seabirds that nest in temperate to arctic oceans throughout the Northern hemisphere. They are very similar in the characteristics of ecology, demography and life history that are thought to determine the extent of differentiation among populations, yet geographic variation in morphology is notably greater in common guillemots. Despite evidence of strong natal philopatry, previous analyses of allozymes and the mitochondrial cytochrome b gene revealed little genetic differentiation among North Atlantic colonies of Brünnich's guillemots. To determine if the more extensive morphological variability in common guillemots reflects greater genetic variability, we sequenced part of the cytochrome b gene for 160 common guillemots from 10 colonies distributed throughout the Northern hemisphere. Genotype frequencies and phylogenetic relationships among genotypes both indicated that Atlantic and Pacific populations are genetically distinct. Genetic divergence among genotypes suggested that differentiation of these populations has resulted from separation by Pleistocene glaciers and the Bering Landbridge, as well as by currently unsuitable breeding habitat in the Arctic Ocean. Cytochrome b genotype frequencies also differed among Atlantic colonies, and appeared to define a cline similar to that described for morphological characters. Analyses of sequence variation suggested that this variation probably results from secondary contact between two refugial populations from the Pleistocene glaciations, rather than from isolation by distance or selection. In contrast, the Atlantic population of Brünnich's guillemots appears to have arisen through recent expansion of a single homogeneous refugial population.

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