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Abstract
Although larch (Larix spp.) trees dominate the Siberian boreal forest, the species’ genetic structure within the world's largest forest biome is still poorly understood. Here, we compile and analyze genetic data from six boreal populations of three putative larch species (Larix sibirica Ledeb., Larix gmelinii (Rupr.) Rupr., and Larix cajanderi Mayr) from disjunct sites distributed across much of the Russian northern taiga between 60 and 170°E. Using nine nuclear microsatellite markers (nSSR), we find high genetic diversity (mean HE = 0.757) and allelic richness (mean AR = 9.289) within all populations. Our analyses reveal two main genetic lineages: a western lineage corresponding to L. sibirica and an eastern lineage comprising L. gmelinii and L. cajanderi. Active hybridization connects these lineages across their contact zone. Our findings not only provide insights into the biogeographic structure and evolution of Eurasia’s boreal forest, but also highlight the need for spatially explicit and better replicated genetic studies to resolve remaining taxonomic uncertainties.