University of Oulu

Alina K. Niskanen, Anna M. Billing, Håkon Holand, Ingerid J. Hagen, Yimen G. Araya-Ajoy, Arild Husby, Bernt Rønning, Ane Marlene Myhre, Peter Sjolte Ranke, Thomas Kvalnes, Henrik Pärn, Thor Harald Ringsby, Sigbjørn Lien, Bernt-Erik Sæther, Stefanie Muff, Henrik Jensen, Consistent scaling of inbreeding depression in space and time in a house sparrow metapopulation, Proceedings of the National Academy of Sciences Jun 2020, 117 (25) 14584-14592; DOI: 10.1073/pnas.1909599117

Consistent scaling of inbreeding depression in space and time in a house sparrow metapopulation

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Author: Niskanen, Alina K.1,2; Billing, Anna M.1; Holand, Håkon1;
Organizations: 1Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
2Ecology and Genetics Research Unit, University of Oulu, 90014 Oulu, Finland
3Department of Aquatic Biodiversity, Norwegian Institute for Nature Research, 7485 Trondheim, Norway
4Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, 75236 Uppsala, Sweden
5Centre for Integrative Genetics, Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, 1433 Ås, Norway
6Centre for Biodiversity Dynamics, Department of Mathematical Sciences, Norwegian University of Science and Technology, 7491 Trondheim, Norway
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.7 MB)
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Language: English
Published: National Academy of Sciences of the United States of America, 2020
Publish Date: 2020-12-08


Inbreeding may increase the extinction risk of small populations. Yet, studies using modern genomic tools to investigate inbreeding depression in nature have been limited to single populations, and little is known about the dynamics of inbreeding depression in subdivided populations over time. Natural populations often experience different environmental conditions and differ in demographic history and genetic composition, characteristics that can affect the severity of inbreeding depression. We utilized extensive long-term data on more than 3,100 individuals from eight islands in an insular house sparrow metapopulation to examine the generality of inbreeding effects. Using genomic estimates of realized inbreeding, we discovered that inbred individuals had lower survival probabilities and produced fewer recruiting offspring than noninbred individuals. Inbreeding depression, measured as the decline in fitness-related traits per unit inbreeding, did not vary appreciably among populations or with time. As a consequence, populations with more resident inbreeding (due to their demographic history) paid a higher total fitness cost, evidenced by a larger variance in fitness explained by inbreeding within these populations. Our results are in contrast to the idea that effects of inbreeding generally depend on ecological factors and genetic differences among populations, and expand the understanding of inbreeding depression in natural subdivided populations.

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Series: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
ISSN-E: 1091-6490
ISSN-L: 0027-8424
Volume: 117
Issue: 25
Pages: 14584 - 14592
DOI: 10.1073/pnas.1909599117
Type of Publication: A1 Journal article – refereed
Field of Science: 1184 Genetics, developmental biology, physiology
Funding: A.K.N. received funding from the Academy of Finland (Project 295204), Finnish Cultural Foundation, and Oskar Huttunen Foundation. This study was funded by the Research Council of Norway (RCN; Projects 221956, 214553, 274930, and 302619), RCN’s Centres of Excellence funding scheme (Project 223257), and European Union Commission (Project METABIRD).
Academy of Finland Grant Number: 295204
Detailed Information: 295204 (Academy of Finland Funding decision)
Copyright information: © 2020 The Authors. Published under the PNAS license. The final publication is available at