No evidence of inbreeding depression in fast declining herds of migratory caribou

• Published in: Journal of Evolutionary Biology
• Main Authors: Gagnon, Marianne, Yannic, Glenn, Perrier, Charles, Côté, Steeve
• Other Authors: Centre d'Etudes Nordiques (CEN), Université Laval Québec (ULaval), Laboratoire d'Ecologie Alpine (LECA ), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Sud )-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Natural Sciences and Engineering Research Council of Canada, Caribou Ungava, Ministere des Forets, de la Faune et des Parcs, Labex, Fonds de Recherche Nature et Technologies du Quebec
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: general effect hypothesis; heterozygosity-fitness correlation; inbreeding depression; migratory caribou; Rangifer tarandus; SNP; [SDV.GEN]Life Sciences [q-bio]/Genetics
• Online Access: https://hal.inrae.fr/hal-02921343; https://hal.inrae.fr/hal-02921343/document; https://hal.inrae.fr/hal-02921343/file/P34.Gagnon_et_al-2019-JEB.pdf; https://doi.org/10.1111/jeb.13533

International audience Identifying inbreeding depression early in small and declining populations is essential for management and conservation decisions. Correlations between heterozygosity and fitness (HFCs) provide a way to identify inbreeding depression without prior knowledge of kinship among individuals. In Northern Quebec and Labrador, the size of two herds of migratory caribou (Riviere-George, RG and Riviere-aux-Feuilles, RAF) has declined by one to two orders of magnitude in the last three decades. This raises the question of a possible increase in inbreeding depression originating from, and possibly contributing to, the demographic decline in those populations. Here, we tested for the association of genomic inbreeding indices (estimated with 22,073 SNPs) with body mass and survival in 400 caribou sampled in RG and RAF herds between 1996 and 2016. We found no association of individual heterozygosity or inbreeding coefficient with body mass or annual survival. Furthermore, those genomic inbreeding indices remained stable over the period monitored. These results suggest that the rapid and intense demographic decline of the herds did not cause inbreeding depression in those populations. Although we found no evidence for HFCs, if demographic decline continues, it is possible that such inbreeding depression would be triggered.