Data from: Phylogeographic patterns of the desert poplar in northwest China shaped by both geology and climatic oscillations

Background: The effects of historical geology and climatic events on the
evolution of plants around the Qinghai-Tibetan Plateau region have been at
the center of debate for years. To identify the influence of the uplift of
the Tianshan Mountains and/or climatic oscillations on the evolution of
plants in arid northwest China, we investigated the phylogeography of the
Euphrates poplar (Populus euphratica) using chloroplast DNA (cpDNA)
sequences and nuclear microsatellites, and estimated its historical
distribution using Ecological Niche Modeling (ENM). Results: We found that
the Euphrates poplar differed from another desert poplar, P. pruinosa, in
both nuclear and chloroplast DNA. The low clonal diversity in both
populations reflected the low regeneration rate by seed/seedlings in many
locations. Both cpDNA and nuclear markers demonstrated a clear divergence
between the Euphrates poplar populations from northern and southern
Xinjiang regions. The divergence time was estimated to be early
Pleistocene based on cpDNA, and late Pleistocene using an Approximate
Bayesian Computation analysis based on microsatellites. Estimated gene
flow was low between these two regions, and the limited gene flow occurred
mainly via dispersal from eastern regions. ENM analysis supported a wider
distribution of the Euphrates poplar at 3 Ma, but a more constricted
distribution during both the glacial period and the interglacial period.
Conclusions: These results indicate that the deformation of the Tianshan
Mountains has impeded gene flow of the Euphrates poplar populations from
northern and southern Xinjiang, and the distribution constriction due to
climatic oscillations further accelerated the divergence of populations
from these regions. To protect the desert poplars, more effort is needed
to encourage seed germination and seedling establishment, and to conserve
endemic gene resources in the northern Xinjiang region.