Conservation management strategy impacts inbreeding and genetic load in scimitar-horned oryx

In an age of habitat loss and overexploitation, small populations, both captive and wild, are increasingly facing the effects of isolation and inbreeding. Genetic management has therefore become a vital tool for ensuring population viability. However, little is known about how the type and intensity of intervention shape the genomic landscape of inbreeding and genetic load. We address this using whole genome sequence data of scimitar-horned oryx (Oryx dammah), an iconic antelope that has been subject to contrasting management strategies since it was declared extinct in the wild. We show that unmanaged populations are enriched for long runs of homozygosity (ROH) and have significantly higher inbreeding coefficients than managed populations. These patterns were associated with a partial deficit of highly deleterious mutations but a considerable excess of weakly deleterious mutations. These findings emphasise the risks associated with multiple generations of inbreeding and highlight the complex dynamics of mutation accumulation and purging in captivity. As wildlife management strategies continue to diversify, our study reinforces the importance of maintaining genome-wide variation in vulnerable populations and has direct implications for one of the largest reintroduction attempts in the world. Significance statement The preservation of genetic variation has long been recognised as a critical component of conservation management. However, recent observations in small and isolated populations have led some to challenge this paradigm. We investigate the impact of contrasting management strategies on the genomic landscape of inbreeding and genetic load in captive populations of scimitar-horned oryx. We reveal how several decades of management have prevented the formation of long runs of homozygosity and buffered the impacts of deleterious mutations. Our findings validate consensus thinking on the importance of genome-wide variation for population viability and have direct implications for future management of threatened species.