Data from: Genomic analysis reveals depression due to both individual and maternal inbreeding in a free-living mammal population

There is ample evidence for inbreeding depression manifested as a
reduction in fitness or fitness-related traits in the focal individual. In
many organisms, fitness is not only affected by genes carried by the
individual, but also by genes carried by their parents, for example if
receiving parental care. While maternal effects have been described in
many systems, the extent to which inbreeding affects fitness directly
through the focal individual, or indirectly through the inbreeding
coefficients of its parents, has rarely been examined jointly. The Soay
sheep study population is an excellent system in which to test for both
effects, as lambs receive extended maternal care. Here, we tested for both
maternal and individual inbreeding depression in three fitness-related
traits (birthweight and weight and hindleg length at 4 months of age) and
three fitness components (first-year survival, adult annual survival and
annual breeding success), using either pedigree-derived inbreeding or
genomic estimators calculated using ~37 000 SNP markers. We found evidence
for inbreeding depression in 4-month hindleg and weight, first-year
survival in males, and annual survival and breeding success in adults.
Maternal inbreeding was found to depress both birthweight and 4-month
weight. We detected more instances of significant inbreeding depression
using genomic estimators than the pedigree, which is partly explained
through the increased sample sizes available. In conclusion, our results
highlight that cross-generational inbreeding effects warrant further
exploration in species with parental care and that modern genomic tools
can be used successfully instead of, or alongside, pedigrees in natural
populations.