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.
Lemmus sequence alignment for the partial dataset (172 bp)
Combined mitochondrial data. Control region: position 1-96; Cytochrome b: position 97-172.
Lemmus alignment partial dataset.fst
Lemmus sequence alignment for the complete dataset (520 bp)
Combined mitochondrial data. Control region: position 1-168; Cytochrome b: position 169-520.
Lemmus alignment complete dataset.fst
Lemmus.partial.11.7.inputBEAST
Input file to BEAST, for analysing the partial dataset using a mutation rate of 11.7 % per million years
Lemmus.partial.11.7.result.BEAST
Tree file obtained from BEAST and summarised in TreeAnnotator. For the partial dataset using a mutation rate of 11.7 % per million years
Lemmus partial_11,7_BEAST_outputTreeAnnotator
Lemmus.partial.30.inputBEAST
Input file to BEAST, for analysing the partial dataset using a mutation rate of 30 % per million years
Lemmus.partial.30.result.BEAST
Tree file obtained from BEAST and summarised in TreeAnnotator. For the partial dataset using a mutation rate of 30 % per million years
Lemmus partial_30_BEAST_outputTreeAnnotator
Lemmus.partial.50.inputBEAST
Input file to BEAST, for analysing the partial dataset using a mutation rate of 50 % per million years
Lemmus.partial.50.result.BEAST
Tree file obtained from BEAST and summarised in TreeAnnotator. For the partial dataset using a mutation rate of 50 % per million years
Lemmus partial_50_BEAST_outputTreeAnnotator
Lemmus.complete.8.9.inputBEAST
Input file to BEAST, for analysing the complete dataset using a mutation rate of 8.9 % per million years
Lemmus.complete.8.9.result.BEAST
Tree file obtained from BEAST and summarised in TreeAnnotator. For the complete dataset using a mutation rate of 8.9 % per million years
Lemmus complete_8,9_BEAST_outputTreeAnnotator
Lemmus.complete.30.inputBEAST
Input file to BEAST, for analysing the complete dataset using a mutation rate of 30 % per million years
Lemmus.complete.30.result.BEAST
Tree file obtained from BEAST and summarised in TreeAnnotator. For the complete dataset using a mutation rate of 30 % per million years
Lemmus complete_30_BEAST_outputTreeAnnotator
Lemmus.complete.50.inputBEAST
Input file to BEAST, for analysing the complete dataset using a mutation rate of 50 % per million years
Lemmus.complete.50.result.BEAST
Tree file obtained from BEAST and summarised in TreeAnnotator. For the complete dataset using a mutation rate of 50 % per million years
Lemmus partial_50_BEAST_outputTreeAnnotator
Lemmus.complete dated.30.inputBEAST
Input file to BEAST, for analysing the complete dataset using a mutation rate of 30 % per million years. Only including the directly dated sequences (Pleistocene & Modern)
Lemmus.complete dated.30.result.BEAST
Tree file obtained from BEAST and summarised in TreeAnnotator. For the complete dataset using a mutation rate of 30 % per million years. Only with dated sequences
Lemmus complete dated_30_BEAST_outputTreeAnnotator
Lemmus.partial.inputMrBayes
Input file to MrBayes for analysing the partial dataset, using Mictotus as an outgroup
Lemmus.partial.result.MrBayes.nex.con
Tree file obtained from MrBayes, for the partial dataset.
Lemmus partial_MrBayes.nex.con.tre