The study of the phylogeny and evolution of small rodents tends to be complicated because of their high evolutionary rates and widespread distribution of the species, even so in the fossil record, being this more notable within the Arvicolinae subfamily. For this reason, the fields of ancient DNA and phylogeography are indispensable for understanding how this evolutionary process took place. This project aims to investigate various small rodents species of Arvicolinae, including lemmings and voles species among others, in order to uncover their demographic histories and phylogenetic evolution since the Middle Pleistocene. The studied samples include several Middle/Early Pleistocene voles and lemming species, as well as a large number of Late Pleistocene and modern ones. During the project, I will generate and analyze the whole mitochondrial and nuclear genomes from the modern and ancient individuals. The primary objective of this project is the evolution of North American Microtus. For this reason, the majority of the samples will come from North American sites. However, I will also work with samples of European origin, to compare the species and phylogenetic evolution of the North American and European Arvicolinae species.