Data from: On the origin of the Norwegian lemming

The Pleistocene glacial cycles resulted in significant changes in species
distributions, and it has been discussed whether this caused increased
rates of population divergence and speciation. One species that is likely
to have evolved during the Pleistocene is the Norwegian lemming (Lemmus
lemmus). However, the origin of this species, both in terms of when and
from what ancestral taxon it evolved, has been difficult to ascertain.
Here, we use ancient DNA recovered from lemming remains from a series of
Late Pleistocene and Holocene sites to explore the species'
evolutionary history. The results revealed considerable genetic
differentiation between glacial and contemporary samples. Moreover, the
analyses provided strong support for a divergence time prior to the Last
Glacial Maximum (LGM), therefore likely ruling out a postglacial
colonization of Scandinavia. Consequently, it appears that the Norwegian
lemming evolved from a small population that survived the LGM in an
ice-free Scandinavian refugium.