title: Ancient DNA analyses exclude humans as the driving force behind late Pleistocene musk ox (Ovibos moschatus) population dynamics.
abstract: The causes of the late Pleistocene megafaunal extinctions are poorly understood. Different lines of evidence point to climate change, the arrival of humans, or a combination of these events as the trigger. Although many species went extinct, others, such as caribou and bison, survived to the present. The musk ox has an intermediate story: relatively abundant during the Pleistocene, it is now restricted to Greenland and the Arctic Archipelago. In this study, we use ancient DNA sequences, temporally unbiased summary statistics, and Bayesian analytical techniques to infer musk ox population dynamics throughout the late Pleistocene and Holocene. Our results reveal that musk ox genetic diversity was much higher during the Pleistocene than at present, and has undergone several expansions and contractions over the past 60,000 years. Northeast Siberia was of key importance, as it was the geographic origin of all samples studied and held a large diverse population until local extinction at approximately 45,000 radiocarbon years before present ((14)C YBP). Subsequently, musk ox genetic diversity reincreased at ca. 30,000 (14)C YBP, recontracted at ca. 18,000 (14)C YBP, and finally recovered in the middle Holocene. The arrival of humans into relevant areas of the musk ox range did not affect their mitochondrial diversity, and both musk ox and humans expanded into Greenland concomitantly. Thus, their population dynamics are better explained by a nonanthropogenic cause (for example, environmental change), a hypothesis supported by historic observations on the sensitivity of the species to both climatic warming and fluctuations.
authors.affiliation: Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK 1350 Copenhagen, Denmark.
authors.forename: Paula F
authors.initials: PF
authors.lastname: Campos
authors.forename: Eske
authors.initials: E
authors.lastname: Willerslev
authors.forename: Andrei
authors.initials: A
authors.lastname: Sher
authors.forename: Ludovic
authors.initials: L
authors.lastname: Orlando
authors.forename: Erik
authors.initials: E
authors.lastname: Axelsson
authors.forename: Alexei
authors.initials: A
authors.lastname: Tikhonov
authors.forename: Kim
authors.initials: K
authors.lastname: Aaris-Sørensen
authors.forename: Alex D
authors.initials: AD
authors.lastname: Greenwood
authors.forename: Ralf-Dietrich
authors.initials: RD
authors.lastname: Kahlke
authors.forename: Pavel
authors.initials: P
authors.lastname: Kosintsev
authors.forename: Tatiana
authors.initials: T
authors.lastname: Krakhmalnaya
authors.forename: Tatyana
authors.initials: T
authors.lastname: Kuznetsova
authors.forename: Philippe
authors.initials: P
authors.lastname: Lemey
authors.forename: Ross
authors.initials: R
authors.lastname: MacPhee
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Norris
authors.forename: Kieran
authors.initials: K
authors.lastname: Shepherd
authors.forename: Marc A
authors.initials: MA
authors.lastname: Suchard
authors.forename: Grant D
authors.initials: GD
authors.lastname: Zazula
authors.forename: Beth
authors.initials: B
authors.lastname: Shapiro
authors.forename: M Thomas P
authors.initials: MT
authors.lastname: Gilbert
mesh_terms: D000818:Animals; D004247:DNA / Q000235:genetics* / Q000266:history; D004272:DNA, Mitochondrial / Q000235:genetics / Q000266:history; D053476:Extinction, Biological; D005580:Fossils; D014644:Genetic Variation; D049690:History, Ancient; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D011157:Population Dynamics; D012418:Ruminants / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial; D004247:DNA