Proceedings of the National Academy of Sciences of the United States of America
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 approximate to 45,000 radiocarbon years before present (14C YBP). Subsequently, musk ox genetic diversity reincreased at ca. 30,000 14C YBP, recontracted at ca. 18,000 14C 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 non-anthropogenic cause (for example, environmental change), a hypothesis supported by historic observations on the sensitivity of the species to both climatic warming and fluctuations.
Original Publication Citation
Campos, P. F., Willerslev, E., Sher, A., Orlando, L., Axelsson, E., Tikhonov, A., . . . Gilbert, M. T. P. (2010). Ancient DNA analyses exclude humans as the driving force behind late pleistocene musk ox (Ovibos moschatus) population dynamics. Proceedings of the National Academy of Sciences of the United States of America, 107(12), 5675-5680. doi:10.1073/pnas.0907189107
Campos, Paula F.; Willerslev, Eske; Sher, Andrei; Orlando, Ludovic; Axelsson, Erik; Tikhonov, Alexei; Aaris-Sorensen, Kim; Greenwood, Alex D.; Kahlke, Ralf-Dietrich; and Kosintsev, Pavel, "Ancient DNA Analyses Exclude Humans as the Driving Force Behind Late Pleistocene Musk Ox (Ovibos moschatus) Population Dynamics" (2010). Biological Sciences Faculty Publications. 285.