Investigating the link between genomic variation and fitness in a Swedish arctic fox population
Inbreeding depression has been documented in various fitness traits in a wide range of species and taxa, however, the mutational basis is not yet well understood. We investigate how putatively deleterious variation influences fitness and is shaped by individual ancestry by sequencing complete genomes of 37 individuals in a natural arctic fox (Vulpes lagopus) population subjected to both inbreeding depression and genetic rescue. We found that individuals with high proportion of loss of function genotypes (LoFs), which are predicted to exert a strong effect on fitness, generally had lower lifetime reproductive success and lived shorter lives compared with individuals with lower proportion of LoFs. We also found that juvenile survival was negatively associated with the proportion of homozygous missense genotypes and positively associated with genome wide heterozygosity. Our results demonstrate that homozygosity of strongly and moderately deleterious mutations can be an important cause of trait specific inbreeding depression in wild populations, and mark an important step towards making more informed decisions using applied conservation genetics.