Detection and Verification of Hybrid Betula nana L. Plants in the Urals

Hybrid plants were verified in Betula nana populations of the Urals by flow cytometry and were especially numerous in the northern part of the region. ITS1 nucleotide sequences were obtained by Sanger sequencing. Based on their analysis, low differentiation was observed for B. nana and B. pubescens and associated with current and ancestral hybridization processes. Intragenomic polymorphism of ITS1 sequences was assessed using the Illumina technology and detected both B. nana and B. pubescens rDNAs in the genomes of first-generation interspecific hybrids.