Data from: The DNA history of a lonely oak: Quercus humboldtii phylogeography in the Colombian Andes

<p>The climatic and geological changes that occurred during the Quaternary, particularly the fluctuations during the glacial and interglacial periods of the Pleistocene, shaped the population demography and geographic distribution of many species. These processes have been studied in several groups of organisms in the northern hemisphere, but their influence on the evolution of Neotropical montane species and ecosystems remains unclear. This study contributes to the understanding of the effect of climatic fluctuations during the late Pleistocene on the evolution of Andean mountain forests. Firstly, by describing the nuclear and plastidic DNA patterns of genetic diversity, structure, historical demography and landscape connectivity of <i>Quercus humboldtii</i>, which is a typical species in northern Andean montane forests. Then, by comparing these patterns with the palynological and evolutionary hypotheses postulated for montane forests of the Colombian Andes under climatic fluctuation scenarios during the Quaternary. Our results indicated that populations of <i>Q. humboldtii</i> have high genetic diversity, a lack of genetic structure, and a historical increase in connectivity from the Last Glacial Maximum (LGM) to the present. Furthermore, our results showed a dramatic reduction in the effective population size followed by an expansion before the LGM, which coincides with the results found by palynological studies, suggesting a change in dominance in Andean forests that may be related to ecological factors rather than climate change.</p>