Genome analyses suggest recent speciation and postglacial isolation in the Norwegian lemming

The Norwegian lemming (<i>Lemmus lemmus</i>) is a small rodent distributed across the Fennoscandian mountain tundra and the Kola Peninsula. The Norwegian lemming likely evolved during the Late Pleistocene and inhabited Fennoscandia shortly prior to the Last Glacial Maximum. However, the exact timing and origins of the species, and its phylogenetic position relative to the closely related Siberian lemming (<i>Lemmus sibiricus</i>) remain disputed. Moreover, the presence of ancient or contemporary gene flow between both species is largely untested. The Norwegian lemming displays characteristic phenotypic and behavioral adaptations (e.g., coat color, aggression) that are not present in other <i>Lemmus</i> species. We generated a de novo genome assembly for the Norwegian lemming and resequenced nine modern and two ancient <i>Lemmus</i> spp. genomes. We show that all <i>Lemmus</i> species form distinct monophyletic clades, with concordant topology between the mitochondrial and nuclear genome phylogenies. The Siberian lemming is divided into two distinct but paraphyletic clades, one in the east and one in the west, where the western clade represents a sister taxon to the Norwegian lemming. We estimate that the Norwegian and western Siberian lemming diverged shortly before the Last Glacial Maximum, making the Norwegian lemming one of the youngest known mammalian species. We did not find any indication of gene flow between <i>L. lemmus</i> and <i>L. sibiricus</i>, suggesting postglacial isolation of <i>L. lemmus</i>. Furthermore, we identify species-specific genomic differences in genes related to coat color and fat transport, which are likely associated with the distinctive coloration and overwintering behavior observed in the Norwegian lemming.

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Publication Details

Journal
Proceedings of the National Academy of Sciences
Published
2025-06-30
DOI
https://doi.org/10.1073/pnas.2424333122
Citations
2
Primary Topic
Animal Ecology and Behavior Studies
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article
Field-Weighted Citation Impact
3.43

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article

Genome analyses suggest recent speciation and postglacial isolation in the Norwegian lemming

Н. Г. Смирнов, Anna V. Goropashnaya, Ivan Pokrovsky, Dorothée Ehrich et al.
2 citations
Proceedings of the National Academy of Sciences
Animal Ecology and Behavior Studies
3.43
article

Genome analyses suggest recent speciation and postglacial isolation in the Norwegian lemming

Н. Г. Смирнов, Anna V. Goropashnaya, Ivan Pokrovsky, Dorothée Ehrich, Monika V. Knul, Love Dalén, Edana Lord, Stefan Prost, Karin Näsvall, Pierre Noiret, David Díez‐del‐Molino, E. A. Kuzmina, Erik Ersmark, John R. Stewart, Vendela Kempe Lagerholm, André E. R. Soares, Mietje Germonpré, Vadim B. Fedorov, Isabelle Sofie Feinauer, Remi‐André Olsen
article en
2 citations

Abstract

The Norwegian lemming (<i>Lemmus lemmus</i>) is a small rodent distributed across the Fennoscandian mountain tundra and the Kola Peninsula. The Norwegian lemming likely evolved during the Late Pleistocene and inhabited Fennoscandia shortly prior to the Last Glacial Maximum. However, the exact timing and origins of the species, and its phylogenetic position relative to the closely related Siberian lemming (<i>Lemmus sibiricus</i>) remain disputed. Moreover, the presence of ancient or contemporary gene flow between both species is largely untested. The Norwegian lemming displays characteristic phenotypic and behavioral adaptations (e.g., coat color, aggression) that are not present in other <i>Lemmus</i> species. We generated a de novo genome assembly for the Norwegian lemming and resequenced nine modern and two ancient <i>Lemmus</i> spp. genomes. We show that all <i>Lemmus</i> species form distinct monophyletic clades, with concordant topology between the mitochondrial and nuclear genome phylogenies. The Siberian lemming is divided into two distinct but paraphyletic clades, one in the east and one in the west, where the western clade represents a sister taxon to the Norwegian lemming. We estimate that the Norwegian and western Siberian lemming diverged shortly before the Last Glacial Maximum, making the Norwegian lemming one of the youngest known mammalian species. We did not find any indication of gene flow between <i>L. lemmus</i> and <i>L. sibiricus</i>, suggesting postglacial isolation of <i>L. lemmus</i>. Furthermore, we identify species-specific genomic differences in genes related to coat color and fat transport, which are likely associated with the distinctive coloration and overwintering behavior observed in the Norwegian lemming.

Proceedings of the National Academy of SciencesVol. 122(28)
Uppsala University (SE), Natural History Museum Vienna (AT), University of Vienna (AT), University of Liège (BE), Stockholm University (SE), Konrad Lorenz Institute for Evolution and Cognition Research (AT), University of Winchester (GB), Science for Life Laboratory (SE), Institute of Natural Sciences (BE), Swedish Museum of Natural History (SE), Wellcome Sanger Institute (GB), South African National Biodiversity Institute (ZA), National Zoological Park (US), Max Planck Institute of Animal Behavior (DE), National Biodiversity Institute (CR), Institute of Plant and Animal Ecology (RU), Centre for Palaeogenetics (SE), Central Research Laboratories (United Kingdom) (GB), UiT The Arctic University of Norway (NO), Bournemouth University (GB)
Royal Swedish Academy of Sciences, Svenska Forskningsrådet Formas, Carl Tryggers Stiftelse för Vetenskaplig Forskning, Vetenskapsrådet, National Institutes of Health
Life below water
Openalex Percentile: Top 8%
Animal Ecology and Behavior Studies
3.43
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