Microsatellite variation and genetic structure of brook trout (Salvelinus fontinalis) populations in Labrador and neighboring Atlantic Canada: evidence for ongoing gene flow and dual routes of post-Wisconsinan colonization

Authors

  • Brettney L. Pilgrim,

    1. Department of Biology, Memorial University of Newfoundland and Labrador, St. John's, Newfoundland and Labrador, A1B 3X9, Canada
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  • Robert C. Perry,

    1. Department of Environment and Conservation, Wildlife Division, Government of Newfoundland and Labrador, Corner Brook, Newfoundland and Labrador, A2H 7S1, Canada
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  • Donald G. Keefe,

    1. Department of Environment and Conservation, Wildlife Division, Government of Newfoundland and Labrador, Corner Brook, Newfoundland and Labrador, A2H 7S1, Canada
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  • Elizabeth A. Perry,

    1. Genomics and Proteomics Facility, CREAIT Network, Memorial University of Newfoundland and Labrador, St. John's, Newfoundland and Labrador, A1B 3X9, Canada
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  • H. Dawn Marshall

    1. Department of Biology, Memorial University of Newfoundland and Labrador, St. John's, Newfoundland and Labrador, A1B 3X9, Canada
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  • Funded by a grant from the Wildlife Division of the Newfoundland and Labrador Department of Environment and Conservation and an NSERC Discovery Grant to H. D. M.

  • Ecology and Evolution 2012; 2(5): 885–898

H. Dawn Marshall, Department of Biology, Memorial University of Newfoundland and Labrador, St. John's, Newfoundland and Labrador, A1B 3X9, Canada. Tel: 709-737-7677; Fax: 709-737-3018; E-mail: dawnm@mun.ca

Abstract

In conservation genetics and management, it is important to understand the contribution of historical and contemporary processes to geographic patterns of genetic structure in order to characterize and preserve diversity. As part of a 10-year monitoring program by the Government of Newfoundland and Labrador, Canada, we measured the population genetic structure of the world's most northern native populations of brook trout (Salvelinus fontinalis) in Labrador to gather baseline data to facilitate monitoring of future impacts of the recently opened Trans-Labrador Highway. Six-locus microsatellite profiles were obtained from 1130 fish representing 32 populations from six local regions. Genetic diversity in brook trout populations in Labrador (average HE= 0.620) is within the spectrum of variability found in other brook trout across their northeastern range, with limited ongoing gene flow occurring between populations (average pairwise FST= 0.139). Evidence for some contribution of historical processes shaping genetic structure was inferred from an isolation-by-distance analysis, while dual routes of post-Wisconsinan recolonization were indicated by STRUCTURE analysis: K= 2 was the most likely number of genetic groups, revealing a separation between northern and west-central Labrador from all remaining populations. Our results represent the first data from the nuclear genome of brook trout in Labrador and emphasize the usefulness of microsatellite data for revealing the extent to which genetic structure is shaped by both historical and contemporary processes.

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