Get access

Parallel and lineage-specific molecular adaptation to climate in boreal black spruce

Authors

  • JULIEN PRUNIER,

    1. Canada Research Chair in Forest and Environmental Genomics, Centre for Forest Research, 1030 avenue de la Médecine, Université Laval, Québec, Québec, Canada G1V 0A6
    2. Institute for Systems and Integrative Biology, 1030 avenue de la Médecine, Université Laval, Québec, Québec, Canada G1V 0A6
    Search for more papers by this author
  • SÉBASTIEN GÉRARDI,

    1. Canada Research Chair in Forest and Environmental Genomics, Centre for Forest Research, 1030 avenue de la Médecine, Université Laval, Québec, Québec, Canada G1V 0A6
    2. Institute for Systems and Integrative Biology, 1030 avenue de la Médecine, Université Laval, Québec, Québec, Canada G1V 0A6
    Search for more papers by this author
  • JÉRÔME LAROCHE,

    1. Institute for Systems and Integrative Biology, 1030 avenue de la Médecine, Université Laval, Québec, Québec, Canada G1V 0A6
    Search for more papers by this author
  • JEAN BEAULIEU,

    1. Canada Research Chair in Forest and Environmental Genomics, Centre for Forest Research, 1030 avenue de la Médecine, Université Laval, Québec, Québec, Canada G1V 0A6
    2. Canadian Wood Fibre Centre, Natural Resources Canada, 1055 rue du P.E.P.S., C.P.10380, Succ. Sainte-Foy, Québec, Québec, Canada G1V 4C7
    Search for more papers by this author
  • JEAN BOUSQUET

    1. Canada Research Chair in Forest and Environmental Genomics, Centre for Forest Research, 1030 avenue de la Médecine, Université Laval, Québec, Québec, Canada G1V 0A6
    2. Institute for Systems and Integrative Biology, 1030 avenue de la Médecine, Université Laval, Québec, Québec, Canada G1V 0A6
    Search for more papers by this author

Jean Bousquet, Fax: 1 418 656 7493; E-mail: jean.bousquet@sbf.ulaval.ca

Abstract

In response to selective pressure, adaptation may follow different genetic pathways throughout the natural range of a species due to historical differentiation in standing genetic variation. Using 41 populations of black spruce (Picea mariana), the objectives of this study were to identify adaptive genetic polymorphisms related to temperature and precipitation variation across the transcontinental range of the species, and to evaluate the potential influence of historical events on their geographic distribution. Population structure was first inferred using 50 control nuclear markers. Then, 47 candidate gene SNPs identified in previous genome scans were tested for relationship with climatic factors using an FST-based outlier method and regressions between allele frequencies and climatic variations. Two main intraspecific lineages related to glacial vicariance were detected at the transcontinental scale. Within-lineage analyses of allele frequencies allowed the identification of 23 candidate SNPs significantly related to precipitation and/or temperature variation, among which seven were common to both lineages, eight were specific to the eastern lineage and eight were specific to the western lineage. The implication of these candidate SNPs in adaptive processes was further supported by gene functional annotations. Multiple evidences indicated that the occurrence of lineage-specific adaptive SNPs was better explained by selection acting on historically differentiated gene pools rather than differential selection due to heterogeneity of interacting environmental factors and pleiotropic effects. Taken together, these findings suggest that standing genetic variation of potentially adaptive nature has been modified by historical events, hence affecting the outcome of recent selection and leading to different adaptive routes between intraspecific lineages.

Get access to the full text of this article

Ancillary