No Pedigree, No Problem: Genomic Inbreeding Tracks Genetic Rescue With High Resolution

With increasing habitat fragmentation and population isolation, inbreeding becomes a pressing concern for the persistence of wildlife populations. Detailed inbreeding monitoring is crucial for assessing extinction risk and evaluating the effectiveness of conservation management strategies. Traditionally, pedigree-based inbreeding estimates have been used. Genomic approaches now provide more powerful alternatives. Here, we compare pedigree and genomic inbreeding estimates in a long-term study of wild bighorn sheep (Ovis canadensis) from Ram Mountain, Alberta, Canada, monitored from 1972 to the present. This population experienced a severe population bottleneck followed by genetic rescue through the translocation of 35 individuals over 13 years. We found that genomic inbreeding coefficients (F _ROH) dropped by 24% after genetic rescue efforts began. In contrast, pedigree inbreeding coefficients (F _PED) increased, likely because greater pedigree depth improved our ability to detect inbreeding in later cohorts, highlighting a methodological bias and the need for genomic monitoring. Our findings show that genomic approaches are more effective in detecting changes in inbreeding over time in wild animals and emphasize the utility of F _ROH for monitoring the genetic outcomes of conservation interventions, particularly where pedigree completeness increases through time.