ANALYSIS OF DNA CONTENT AND NUCLEAR MICROSATELLITE LOCI OF SOME Betula L. REPRESENTATIVES
S. O. Medvedeva1, O. E. Cherepanova1, E. G. Filippov1, A. Yu. Teptina2
1Botanical Garden, Russian Academy of Sciences, Ural Branch, Yekaterinburg, Russian Federation
2Ural Federal University, Yekaterinburg, Russian Federation
Keywords: hybridization, dwarf birch, genome size, DNA content, fragment analyses
Abstract
Dwarf birch ( Betula nana L.) is a circumpolar low shrub common in the northern hemisphere. Previously, it was suggested that dwarf birch hybridize with a sympathetic species - the downy birch ( Betula pubescens Ehrh.), with the formation of triploid hybrids in the northern regions of Western Eurasia. Data on the presence and intensity of these species hybridization on the territory of the Russian Federation are scarce and require additional study and verification. The purpose of this study was to study the ploidy level of some birch representatives growing in the mountain tundra of the Altai Mountain range to identify hybrid forms. The work used the flow cytometry method in combination with the analysis of nuclear microsatellite loci. The average DNA content of the studied dwarf birch and silver birch ( B. pendula Roth) samples was 2С = 0.966 pg and 2С = 0.974 pg correspondingly, while DNA content of the putative hybrid sample was 1.46 times higher 2C = 1.413 pg, indicating its probable triploid genome. Analysis of nuclear microsatellite loci confirmed the data obtained by flow cytometry. It was shown that nuclear loci L3.1, L7.3, L1.10, L5.4 are most suitable for identifying triploid hybrid birch samples. The work performed confirms the existence of rare triploid hybrids dwarf birch and downy birch in populations of dwarf birch trees growing in the mountain tundra forest in Altai. The analysis shows that the flow cytometry method in combination with microsatellite analysis is an effective tool for searching and verifying triploid birch hybrids.
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