Demographic history and genomic consequences of 10,000 generations of isolation in a wild mammal.

Wang, Xuejing; Peischl, Stephan; Heckel, Gerald (2023). Demographic history and genomic consequences of 10,000 generations of isolation in a wild mammal. Current biology, 33(10), 2051-2062.e4. Cell Press 10.1016/j.cub.2023.04.042

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Increased human activities caused the isolation of populations in many species-often associated with genetic depletion and negative fitness effects. The effects of isolation are predicted by theory, but long-term data from natural populations are scarce. We show, with full genome sequences, that common voles (Microtus arvalis) in the Orkney archipelago have remained genetically isolated from conspecifics in continental Europe since their introduction by humans over 5,000 years ago. Modern Orkney vole populations are genetically highly differentiated from continental conspecifics as a result of genetic drift processes. Colonization likely started on the biggest Orkney island and vole populations on smaller islands were gradually split off, without signs of secondary admixture. Despite having large modern population sizes, Orkney voles are genetically depauperate and successive introductions to smaller islands resulted in further reduction of genetic diversity. We detected high levels of fixation of predicted deleterious variation compared with continental populations, particularly on smaller islands, yet the fitness effects realized in nature are unknown. Simulations showed that predominantly mildly deleterious mutations were fixed in populations, while highly deleterious mutations were purged early in the history of the Orkney population. Relaxation of selection overall due to benign environmental conditions on the islands and the effects of soft selection may have contributed to the repeated, successful establishment of Orkney voles despite potential fitness loss. Furthermore, the specific life history of these small mammals, resulting in relatively large population sizes, has probably been important for their long-term persistence in full isolation.

Item Type:

Journal Article (Original Article)

Division/Institute:

09 Interdisciplinary Units > Next Generation Sequencing (NGS) Platform
08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE)
08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Population Genetics
08 Faculty of Science > Department of Biology > Bioinformatics and Computational Biology

UniBE Contributor:

Wang, Xuejing, Peischl, Stephan, Heckel, Gerald

Subjects:

500 Science > 570 Life sciences; biology

ISSN:

1879-0445

Publisher:

Cell Press

Language:

English

Submitter:

Pubmed Import

Date Deposited:

15 May 2023 12:20

Last Modified:

22 Dec 2023 15:57

Publisher DOI:

10.1016/j.cub.2023.04.042

PubMed ID:

37178689

Uncontrolled Keywords:

Microtus arvalis Orkney vole bottleneck conservation genomics deleterious variation demography human introduction island population mutation load rodent

BORIS DOI:

10.48350/182542

URI:

https://boris.unibe.ch/id/eprint/182542

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