1. Department of Evolutionary Biology, Zoological Institute, University of Copenhagen, Universitetsparken 15, Denmark DK-2100 Ø.
2. Henry Wellcome Ancient Biomolecules Centre, Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
3. Department of Statistics, University of Oxford, 1 South Parks Road, Oxford OX1 3TG, UK.
4. Soil Cryology Laboratory, Institute for PhysicoChemical and Biological Problems in Soil Science, Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russia.