TrnL-trnfF cpDNA polymorphism in some representatives of the genus Betula

Abstract

We present preliminary results of the trnL-trnF cpDNA region analysis for some representatives of the g. Betula, out of which B. procurva can be considered the most interesting. The disjunctive range of this species is confined to the mountain system in southeast Central Asia (Pamir-Alai). The occurrence of the birch is isolated from the main range in the mountainous part of the Urals, in the boreal forests zone and in the Trans-Ural forest-steppe. Due to high interspecific hybridization and population variability of the g. Betula, doubts were raised about the correct identification of the representatives of B. procurva. The studied genetic variability and population structure of B. procurva, B. nana, B. pubescens, B. turkestanica, B. tianshanica and B. pendula species indicate active introgression and hybridization processes. Polymorphism in all groups is significantly reduced, increasing slightly when comparing the most distant groups. The matching of the B. procurva cpDNA haplotypes (GBS) with B. pendula, B. nana, and B. pubescens shows that this trnL-trnF cpDNA site cannot be used for molecular identification of birch species by barcoding as a single marker, but this marker use is possible for determination of certain B. procurva population. Based on the studied cpDNA region (trnL-F) we found a clear geographic subdivision in B. procurva populations of the Trans-Urals and Central Asia,.