Ancient and Modern Hybridization of Siberian Stone Pine and Dwarf Siberian Pine in the South of Yakutia

The hybridization zone on the northern border of the overlapping ranges at the junction of the Prilensky Plateau with the Stanovoy and Aldan highlands is studied using the analysis of the genotypes of adult plants of dwarf Siberian pine, Pinus pumila (Pall.) Regel, and Siberian stone pine, Pinus sibirica Du Tour, based on allozyme (nuclear codominant markers with biparental inheritance) and mtDNA data. We obtain evidence of modern hybridization of these species, as well as past hybridization events. Our study reveals that, in the conditions of Southern Yakutia, hybridization takes place mainly unidirectionally with an asymmetric flow of genes between species. The replacement of the mitochondrial genomes of Pinus sibirica with the genomes of Pinus pumila is noted in most of the studied samples from the sympatry zone. This phenomenon can be adaptive and contribute to the expansion of the distribution range of Siberian stone pine.