Publications (4)13.17 Total impact
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Article: Out of America: ancient DNA evidence for a new world origin of late quaternary woolly mammoths.
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ABSTRACT: Although the iconic mammoth of the Late Pleistocene, the woolly mammoth (Mammuthus primigenius), has traditionally been regarded as the end point of a single anagenetically evolving lineage, recent paleontological and molecular studies have shown that successive allopatric speciation events must have occurred within Pleistocene Mammuthus in Asia, with subsequent expansion and hybridization between nominal taxa [1, 2]. However, the role of North American mammoth populations in these events has not been adequately explored from an ancient-DNA standpoint. To undertake this task, we analyzed mtDNA from a large data set consisting of mammoth samples from across Holarctica (n = 160) and representing most of radiocarbon time. Our evidence shows that, during the terminal Pleistocene, haplotypes originating in and characteristic of New World populations replaced or succeeded those endemic to Asia and western Beringia. Also, during the Last Glacial Maximum, mammoth populations do not appear to have suffered an overall decline in diversity, despite differing responses on either side of the Bering land bridge. In summary, the "Out-of-America" hypothesis holds that the dispersal of North American woolly mammoths into other parts of Holarctica created major phylogeographic structuring within Mammuthus primigenius populations, shaping the last phase of their evolutionary history before their demise.Current Biology 10/2008; 18(17):1320-6. · 9.65 Impact Factor -
Article: Late Quaternary loss of genetic diversity in muskox (Ovibos).
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ABSTRACT: The modern wildherd of the tundra muskox (Ovibos moschatus) is native only to the New World (northern North America and Greenland), and its genetic diversity is notably low. However, like several other megafaunal mammals, muskoxen enjoyed a holarctic distribution during the late Pleistocene. To investigate whether collapse in range and loss of diversity might be correlated, we collected mitochondrial sequence data (hypervariable region and cytochrome b) from muskox fossil material recovered from localities in northeastern Asia and the Arctic Archipelago of northern North America, dating from late Pleistocene to late Holocene, and compared our results to existing databases for modern muskoxen. Two classes of haplotypes were detected in the fossil material. "Surviving haplotypes" (SHs), closely similar or identical to haplotypes found in modern muskoxen and ranging in age from approximately 22,000 to approximately 160 yrbp, were found in all New World samples as well as some samples from northeastern Asia. "Extinct haplotypes" (EHs), dating between approximately 44,000 and ~18,000 yrbp, were found only in material from the Taimyr Peninsula and New Siberian Islands in northeastern Asia. EHs were not found in the Holocene muskoxen specimens available for this study, nor have they been found in other studies of extant muskox populations. We provisionally interpret this evidence as showing that genetic variability was reduced in muskoxen after the Last Glacial Maximum but before the mid-Holocene, or roughly within the interval 18,000-4,000 yrbp. Narrowing this gap further will require the recovery of more fossils and additional genetic information from this interval.BMC Evolutionary Biology 02/2005; 5:49. · 3.52 Impact Factor -
Article: Paleoclimatic implications of oxygen isotopic variation in late Pleistocene and Holocene tusks of Mammuthus primigenius from northern Eurasia
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ABSTRACT: To understand the role of climate change in the extinction of Mammuthus primigenius in Eurasia, we examine spatial and temporal variations in growth increment and oxygen isotope (δ18O) profiles of radiocarbon dated mammoth tusks. We serially sampled tusk dentin in late Pleistocene tusks from the Taimyr Peninsula and Chukotka and Holocene tusks from Wrangel Island for a total of 241 oxygen isotope analyses from 11 tusks. Most sample series spanned 2–3 years of tusk growth. Differences in mean δ18O values among the Taimyr tusks correlate with δ18O values in corresponding intervals in the Greenland ice sheet and with regional paleoclimate reconstructions. The longitudinal gradient in δ18O values of late Pleistocene tusks (−0.064‰/degree) is similar to the modern meteoric water gradient (−0.064 to −0.048‰/degree). The temporal gradient in mean tusk δ18O in Taimyr from an interstadial during MIS 3 to a stadial during MIS 2 (4.0‰) is similar to the gradient in easternmost Siberia from an interstadial during MIS 3 to the middle Holocene (4.8‰). Seasonality in Chukotka during the late Pleistocene does not appear to be different from that on Wrangel Island during the Holocene. Our results suggest that climate change as recorded by δ18O values of mammoth tusks may not have been the direct cause of the extinction of Eurasian mammoths.Quaternary International. -
Article: Radiocarbon Chronologies and Extinction Dynamics of the Late Quaternary Mammalian Megafauna of the Taimyr Peninsula, Russian Federation
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ABSTRACT: This paper presents 75 new radiocarbon dates based on late Quaternary mammal remains recovered from eastern Taimyr Peninsula and adjacent parts of the northern Siberian lowlands, Russian Federation, including specimens of woolly mammoth (Mammuthus primigenius), steppe bison (Bison priscus), muskox (Ovibos moschatus), moose (Alces alces), reindeer (Rangifer tarandus), horse (Equus caballus) and wolf (Canis lupus). New evidence permits reanalysis of megafaunal extinction dynamics in the Asian high Arctic periphery. Increasingly, radiometric records of individual species show evidence of a gap at or near the Pleistocene/Holocene boundary (PHB). In the past, the PHB gap was regarded as significant only when actually terminal, i.e., when it marked the apparent “last” occurrence of a species (e.g., current “last” occurrence date for woolly mammoth in mainland Eurasia is 9600 yr bp ). However, for high Arctic populations of horses and muskoxen the gap marks an interruption rather than extinction, because their radiocarbon records resume, nearly simultaneously, much later in the Holocene. Taphonomic effects, ΔC14 flux, and biased sampling are unlikely explanations for these hiatuses. A possible explanation is that the gap is the signature of an event, of unknown nature, that prompted the nearly simultaneous crash of many megafaunal populations in the high Arctic and possibly elsewhere in Eurasia.Journal of Archaeological Science.
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2005
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Russian Academy of Sciences
- Zoological Institute
Moscow, Moscow, Russia
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