Population structure and genie diversity in tamarack, Larixlaricina (Du Roi) K. Koch

Abstract

Levels of electrophoretically detectable variation at 19 loci were estimated in 36 populations representing the natural range of Larixlaricina (Du Roi) K. Koch. Results of this survey indicated that the species has levels of genic variation comparable with those of other species of woody perennials with extensive transcontinental ranges. There was no evidence of significant departures from Hardy–Weinberg expectation. However, on average, populations of this species were more differentiated and more genetically divergent from one another compared with many randomly mating tree species. A discriminant analysis of the genotypic structure of the populations analyzed indicated a general east versus west pattern, with populations in the Great Lakes basin being further differentiated. Present-day population distribution, population density, and reinvasion routes after the last glaciation could account for the observed patterns of genic variation.