Rise and Fall of the Beringian Steppe Bison

Henry Wellcome Ancient Biomolecules Centre, Oxford University, South Parks Road, Oxford OX13PS, UK.
Science (Impact Factor: 33.61). 12/2004; 306(5701):1561-5. DOI: 10.1126/science.1101074
Source: PubMed


The widespread extinctions of large mammals at the end of the Pleistocene epoch have often been attributed to the depredations
of humans; here we present genetic evidence that questions this assumption. We used ancient DNA and Bayesian techniques to
reconstruct a detailed genetic history of bison throughout the late Pleistocene and Holocene epochs. Our analyses depict a
large diverse population living throughout Beringia until around 37,000 years before the present, when the population's genetic
diversity began to decline dramatically. The timing of this decline correlates with environmental changes associated with
the onset of the last glacial cycle, whereas archaeological evidence does not support the presence of large populations of
humans in Eastern Beringia until more than 15,000 years later.

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    • "enough to support human populations. Mandryk et al. (2001) suggest that did not occur until after ∼12 ka, a model consistent with a separation of Beringian and southern bison herds until after ∼12.5 ka (MacDonald and Cook 2009; Shapiro et al. 2004; Wilson et al. 2008). Glaciation along the western slope of the Cordilleran ice sheet was somewhat discontinuous, with glacial lobes reaching the sea intermittently along the coasts of what is now Alaska and western Canada and only coalescing at higher elevations (Clague et al. 2004; Kaufman and Manley 2004). "
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    ABSTRACT: A substantial amount of archaeological data suggests groups with markedly different lithic technologies and subsistence adaptations were widespread throughout both American continents by ∼13–13.5 ka. While there are fewer archaeological sites credibly dated to ∼13.5–15.5 ka, they are sufficient to indicate human foragers occupied at least the Pacific coasts of both continents and probably interior continental locations as well. Assuming it required at least 500–2000 years for initial populations to expand throughout these regions, the first colonists must have begun to spread throughout the Americas south of the Laurentide and Cordilleran ice sheets well before post-glacial global warming at 14.5 ka resulted in the melting of the ice sheets and a rapid rise in sea levels. The European and Asian gateway regions to the Americas were occupied by ∼35 ka, and the initial colonization likely postdates this interval. Genetic data suggest the first colonists derive from populations that occupied the Altai Mountains area of central Asia sometime before ∼24 ka, but this hypothesis is based on the modern distribution of haplogroups, and the locations of their ancestral populations at the time they diverged from parent Eurasian populations is unknown. The Altai region is equidistant from both the Atlantic and Pacific gateways to the Americas, and the direction from which the first Americans arrived is a matter of speculation. There are no empirical data supporting the genetic-based hypothesis that there was a population " standstill " in interior Beringia for thousands of years. If there was such a standstill, it more likely occurred in coastal refugia or in other areas in northeast Asia. Scattered data suggest the possibility the Americas were initially occupied sometime prior to ∼17 ka, but these need to be confirmed before they are widely accepted. Of the three most viable hypotheses for the peopling of the Americas, a Clovis First – Ice-free Corridor model appears to be dead and buried; an Atlantic Ice Shelf – Solutrean Origin model is untested, with no empirical data either supporting or falsifying the model; a Pacific coastal model may be the most viable explanation for the initial peopling of the Americas, but also has limited empirical support. This model suggests that boat-using foragers, with an adaptation to the shorelines and estuaries of the Pacific Rim, moved around the margins of the northern Pacific into North and South America before expanding into interior continental regions. Such a migration likely occurred during or prior to the last full glacial.
    Full-text · Article · Jul 2015
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    • "A key conservation concern for small, fragmented populations is the loss of genetic diversity. DNA analysis of prehistoric bones can help to determine the natural level of genetic diversity within a species prior to its decline, thus providing a baseline against which to compare current populations (e.g., Bouzat et al. 1998, Shapiro et al. 2004, Chan et al. 2005). This may, in future, lead to the reintroduction of lost genetic diversity into extant species using gene splicing technologies . "
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    ABSTRACT: Paleornithology, the study of fossil or ancient bird remains, provides an important context for understanding the biology, evolutionary history, and ecology of living birds. Recent technological and methodological advances in the field of paleornithology have opened up the potential to extract new pools of information from fossil bird remains, and hence provide new insights into the histories of living birds. Here we review some of these advances, covering aspects of ancient DNA and protein analyses, sedimentary proxies for birds, stable isotope analyses, coprolite analyses, high-resolution computed tomography, paleoneurology, finite elements analysis, and paleohistology. These new advances offer exciting prospects for the future of paleornithology, but also reaffirm the importance of basic fieldwork, exploration and the discovery of new fossil specimens, museum archives in which to curate the specimens, and traditional morphological approaches to studying the fossil remains.
    Full-text · Article · Apr 2015 · The Auk
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    • "However, rising sea levels during the interglacial periods inundated continental shelves and enlarged marginal seas on a global scale15. These cyclic changes in habitat availability likely led to repeated range expansions and contractions, influencing the population dynamics of various taxa1617. "
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    ABSTRACT: Glacial cycles of the Quaternary have heavily influenced the demographic history of various species. To test the evolutionary impact of palaeo-geologic and climatic events on the demographic history of marine taxa from the coastal Western Pacific, we investigated the population structure and demographic history of two economically important fish (Trichiurus japonicus and T. nanhaiensis) that inhabit the continental shelves of the East China and northern South China Seas using the mitochondrial cytochrome b sequences and Bayesian Skyline Plot analyses. A molecular rate of 2.03% per million years, calibrated to the earliest flooding of the East China Sea shelf (70-140 kya), revealed a strong correlation between population sizes and primary production. Furthermore, comparison of the demographic history of T. japonicus populations from the East China and South China Seas provided evidence of the postglacial development of the Changjiang (Yangtze River) Delta. In the South China Sea, interspecific comparisons between T. japonicus and T. nanhaiensis indicated possible evolutionary responses to changes in palaeo-productivity that were influenced by East Asian winter monsoons. This study not only provides insight into the demographic history of cutlassfish but also reveals potential clues regarding the historic productivity and regional oceanographic conditions of the Western Pacific marginal seas.
    Full-text · Article · Sep 2014 · Scientific Reports
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