Population genomics of the muskox' resilience in the near absence of genetic variation.

Pečnerová P, Lord E, Garcia-Erill G, Hanghøj K, Rasmussen MS, Meisner J, Liu X, van der Valk T, Santander CG, Quinn L, Lin L, Liu S, Carøe C, Dalerum F, Götherström A, Måsviken J, Vartanyan S, Raundrup K, Al-Chaer A, Rasmussen L, Hvilsom C, Heide-Jørgensen MP, Sinding MS, Aastrup P, Van Coeverden de Groot PJ, Schmidt NM, Albrechtsen A, Dalén L, Heller R, Moltke I, Siegismund HR

Mol. Ecol. 33 (2) e17205 [2024-01-00; online 2023-11-16]

Genomic studies of species threatened by extinction are providing crucial information about evolutionary mechanisms and genetic consequences of population declines and bottlenecks. However, to understand how species avoid the extinction vortex, insights can be drawn by studying species that thrive despite past declines. Here, we studied the population genomics of the muskox (Ovibos moschatus), an Ice Age relict that was at the brink of extinction for thousands of years at the end of the Pleistocene yet appears to be thriving today. We analysed 108 whole genomes, including present-day individuals representing the current native range of both muskox subspecies, the white-faced and the barren-ground muskox (O. moschatus wardi and O. moschatus moschatus) and a ~21,000-year-old ancient individual from Siberia. We found that the muskox' demographic history was profoundly shaped by past climate changes and post-glacial re-colonizations. In particular, the white-faced muskox has the lowest genome-wide heterozygosity recorded in an ungulate. Yet, there is no evidence of inbreeding depression in native muskox populations. We hypothesize that this can be explained by the effect of long-term gradual population declines that allowed for purging of strongly deleterious mutations. This study provides insights into how species with a history of population bottlenecks, small population sizes and low genetic diversity survive against all odds.

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PubMed 37971141

DOI 10.1111/mec.17205

Crossref 10.1111/mec.17205

Publications 9.5.0