Genetic variability of Prunus padus (Rosaceae) elaborates “a new Eurasian phylogeographical paradigm”

Abstract

The extent of glacial survival of woody plants in temperate Asia is still poorly known. A reliable way to clarify this issue in the absence of sufficient paleontological data is a phylogeographic analysis of contemporary populations. A recent study of Juniperus communis genetic diversity in Eurasia suggested that this species with wide ecological tolerance survived the glaciation in many periglacial microrefugia at high latitudes and subsequently spread to new areas during interglacials (Hantemirova et al. in J Biogeogr 44:271–282, 2017. https://doi.org/10.1111/jbi.12867). This pattern was termed a “new Eurasian phylogeographical paradigm” as opposed to survival in few major refugia. We have tested the proposed “paradigm” with another hardy species with wide Eurasian area, Prunus padus, to find out if any general phylogeographic patterns may exist for cold-tolerant Eurasian arboreal plant species. We interpret the observed genetic structure [nuclear (ITS) and plastid DNA] of the Eurasian populations of P. padus as plausibly resulted from at least two cycles of glacial survivals in refugia followed by post-glacial colonization events. The species likely originated in East Asia and subsequently spread across all Eurasia. Its continuous range had been fragmented by early-Pleistocene glaciations, when the species survived in the Caucasian and Far Eastern refugia as well as in northern periglacial microrefugia with an active gene flow between them. The known major glacial refugia, such as Iberian Peninsula, the Colchis, the Southern Urals, and the Beringia, played little role as a source of the species post-glacial expansion.