Summary
Published in Journal of Biogeography 43(6): 1227-1241. https://doi.org/10.1111/jbi.12675
Aim : Tamarack (Larix laricina) is an early-successional transcontinental boreal conifer occurring within the spruce-fir dominated forest. The aim was to infer the species biogeographical history and to assess the putative genetic imprint left by interspecific competition during post-glacial migration, using cytoplasmic DNA and fossil data.
Location: Forty-five locations were sampled across the transcontinental range spanning the North American boreal forest.
Methods: A total of 621 trees were scanned for mitochondrial and chloroplast DNA polymorphisms to reveal geographical patterns of genetic diversity, differentiation, and population structure throughout the species range. Published pollen records were analysed to assess the chronology of post-glacial colonization of Larix sp. relative to more competitive tree taxa, Picea sp. and Abies sp..
Results: Genotyping resulted in two mitotypes (one locus) and 24 chlorotypes (three cpSSR loci). Bayesian assignment test based on cpDNA data detected three groups: eastern North America, western North America and Alaska. CpDNA population differentiation was higher in the western part of the range relative to the eastern part. Post-glacial colonization chronology derived from fossil data indicated that Larix colonized western North America at least 4000 years after Picea and Abies, but shortly preceded them in eastern North America.
Main conclusions: Cytoplasmic and fossil data provided support for four distinct glacial lineages. Two lineages would have persisted south of the Laurentide ice sheet, while the two remaining ones likely originate from northern refugia located in Beringia and Labrador. Larix establishment was possibly hindered by earlier establishment of more competitive taxa in western North America, which resulted in high genetic differentiation among western populations. These results provide support for a putative role of interspecific competition in structuring the standing genetic variation at the time of post-glacial colonization.
Sector(s):
Forests
Categorie(s):
Scientific Article
Theme(s):
Forest Genetics, Forestry Research, Forests
Departmental author(s):
Author(s)
WARREN, Emile, Guillaume DE LAFONTAINE, Sébastien GÉRARDI, Sauphie SENNEVILLE, Jean BEAULIEU, Martin PERRON, Juan P. JARAMILLO-CORREA and Jean BOUSQUET
Year of publication :
2016
Format :
Paper
How to get the publication :
Keywords :
ADN chloroplastique et mitochondriale, diversité génétique, refuge glaciaire, colonisation pots-glaciaire, compétition interspécifique, mélèze laricin, amélioration génétique des arbres, Larix laricina, article scientifique de recherche forestière, forest tree improvement, choloroplast and mitochondrial DNA, genetic diversity, glacial refugia, post-glacial colonization, interspecific competition
