Reduced Genetic Load and Inbreeding in Reintroduced African Wild Dogs Reflect the Benefits of Admixture.

Conservation translocations have become important assets in saving African wild dogs (Lycaon pictus) from local extinction, which have declined drastically due to anthropogenic pressures. In South Africa, wild dogs were eradicated except for a small, isolated population remaining in Kruger National Park. Due to reintroductions into private reserves, the country now holds a viable metapopulation of over 150 individuals that is used as a donor to repopulate other countries in southern Africa. This Range Expansion Project allows a unique opportunity to quantify the genomic effect of founder events, population isolation and conservation translocations. For this purpose, we harvested 30 whole genomes of wild dogs from Kruger, private reserves and outside protected areas. Demographic reconstructions indicate that populations were historically large (10,000-40,000 individuals) but began declining gradually ~500-100 kya, coinciding with Mid-Pleistocene climate shifts, followed by a sharp collapse ~2-0.8 kya. The Kruger population showed a substantially higher genetic load and a greater extent of runs of homozygosity (ROHs), indicating that its reduced genetic variation is driven primarily by inbreeding rather than demographic history. In contrast, reintroduced populations in private reserves exhibited the highest genetic diversity and the lowest genetic load. The short ROHs and close genetic affinity to an individual from Kenya support the view that wild dogs historically functioned as a largely panmictic species, and that reconnecting isolated populations can restore evolutionary potential. The absence of drift and relaxed selection implies that genetic resilience can be restored through population admixture, providing valuable guidance for managing threatened species.