Genetic rescue in an inbred Arctic fox (Vulpes lagopus) population

• Published in: Proceedings of the Royal Society B: Biological Sciences
• Main Authors: Hasselgren, Malin, Angerbjörn, Anders, Eide, Nina E., Erlandsson, Rasmus, Flagstad, Øystein, Landa, Arild, Wallén, Johan, Norén, Karin
• Format: Text
• Language: English
• Published: The Royal Society 2018
• Subjects: Ecology; Arctic; Arctic Fox; Vulpes lagopus
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5897638/; http://www.ncbi.nlm.nih.gov/pubmed/29593110; https://doi.org/10.1098/rspb.2017.2814

Isolation of small populations can reduce fitness through inbreeding depression and impede population growth. Outcrossing with only a few unrelated individuals can increase demographic and genetic viability substantially, but few studies have documented such genetic rescue in natural mammal populations. We investigate the effects of immigration in a subpopulation of the endangered Scandinavian arctic fox (Vulpes lagopus), founded by six individuals and isolated for 9 years at an extremely small population size. Based on a long-term pedigree (105 litters, 543 individuals) combined with individual fitness traits, we found evidence for genetic rescue. Natural immigration and gene flow of three outbred males in 2010 resulted in a reduction in population average inbreeding coefficient (f), from 0.14 to 0.08 within 5 years. Genetic rescue was further supported by 1.9 times higher juvenile survival and 1.3 times higher breeding success in immigrant first-generation offspring compared with inbred offspring. Five years after immigration, the population had more than doubled in size and allelic richness increased by 41%. This is one of few studies that has documented genetic rescue in a natural mammal population suffering from inbreeding depression and contributes to a growing body of data demonstrating the vital connection between genetics and individual fitness.