2026/06/02 by Alessandro V. Pinto, K. Lee, Kiran G. L. Lee +9 · 1 voice
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · Environmental Science · #Animal Behavior and Reproduction #Avian ecology and behavior #Genetic diversity and population structure
paper · doi:10.21203/rs.3.rs-9579877/v2
crossref issued 2026/06/02 · crossref published 2026/06/02 · openalex publication_date 2026/06/02 · crossref created 2026/06/02 · crossref deposited 2026/06/02 · crossref indexed 2026/06/02 · openalex created_date 2026/06/03 · openalex updated_date 2026/07/15
Abstract Inbreeding depression - wherein an increase in homozygosity due to mating between relatives causes fitness loss - is a well-established phenomenon, and a well-known threat to small and endangered populations. However, few studies have examined intergenerational inbreeding effects, i.e. the effect of parental homozygosity on offspring fitness. Here, we use a dataset of 1,019 individuals from the long-term study of the Seychelles warbler (Acrocephalus sechellensis) population on Cousin Island, to test intergenerational inbreeding depression. We use inbreeding coefficients (FROH) generated from imputed low-coverage whole-genome sequences and assess how parental FROH predicts first-year survival, lifespan, and productivity. High levels of extra-pair paternity combined with accurate molecular parentage assignment allows us to separate the contributions of genetic and social fathers. We find evidence of individual inbreeding depression in lifespan and lifetime reproductive success, but limited evidence of intergenerational effects. Paternal homozygosity was found to have no effect on fitness, while maternal homozygosity reduced first-year survival only when sibling competition was also present. We also found no evidence that environmental conditions or breed group structure mediated inbreeding depression.