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Scott A. Elias - One of the best experts on this subject based on the ideXlab platform.
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arctic Beringia and native american origins
PaleoAmerica, 2020Co-Authors: John F. Hoffecker, Scott A. Elias, Olga PotapovaAbstract:The central lowland of Beringia (aka the Bering land bridge) has been viewed alternately as a barrier or a refugium to the Native American founder population during the Last Glacial Maximum (LGM). ...
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environmental selection during the last ice age on the mother to infant transmission of vitamin d and fatty acids through breast milk
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Leslea J Hlusko, John F. Hoffecker, Scott A. Elias, Joshua P Carlson, George Chaplin, Michaela Huffman, Nina G Jablonski, Tesla A Monson, Dennis H Orourke, Marin A PilloudAbstract:Because of the ubiquitous adaptability of our material culture, some human populations have occupied extreme environments that intensified selection on existing genomic variation. By 32,000 years ago, people were living in Arctic Beringia, and during the Last Glacial Maximum (LGM; 28,000–18,000 y ago), they likely persisted in the Beringian refugium. Such high latitudes provide only very low levels of UV radiation, and can thereby lead to dangerously low levels of biosynthesized vitamin D. The physiological effects of vitamin D deficiency range from reduced dietary absorption of calcium to a compromised immune system and modified adipose tissue function. The ectodysplasin A receptor ( EDAR ) gene has a range of pleiotropic effects, including sweat gland density, incisor shoveling, and mammary gland ductal branching. The frequency of the human-specific EDAR V370A allele appears to be uniquely elevated in North and East Asian and New World populations due to a bout of positive selection likely to have occurred circa 20,000 y ago. The dental pleiotropic effects of this allele suggest an even higher occurrence among indigenous people in the Western Hemisphere before European colonization. We hypothesize that selection on EDAR V370A occurred in the Beringian refugium because it increases mammary ductal branching, and thereby may amplify the transfer of critical nutrients in vitamin D-deficient conditions to infants via mothers’ milk. This hypothesized selective context for EDAR V370A was likely intertwined with selection on the fatty acid desaturase ( FADS ) gene cluster because it is known to modulate lipid profiles transmitted to milk from a vitamin D-rich diet high in omega-3 fatty acids.
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Beringia and the global dispersal of modern humans.
Evolutionary anthropology, 2016Co-Authors: John F. Hoffecker, Scott A. Elias, Dennis H. O'rourke, G. Richard Scott, Nancy H. BigelowAbstract:Until recently, the settlement of the Americas seemed largely divorced from the out-of-Africa dispersal of anatomically modern humans, which began at least 50,000 years ago. Native Americans were thought to represent a small subset of the Eurasian population that migrated to the Western Hemisphere less than 15,000 years ago. Archeological discoveries since 2000 reveal, however, that Homo sapiens occupied the high-latitude region between Northeast Asia and northwest North America (that is, Beringia) before 30,000 years ago and the Last Glacial Maximum (LGM). The settlement of Beringia now appears to have been part of modern human dispersal in northern Eurasia. A 2007 model, the Beringian Standstill Hypothesis, which is based on analysis of mitochondrial DNA (mtDNA) in living people, derives Native Americans from a population that occupied Beringia during the LGM. The model suggests a parallel between ancestral Native Americans and modern human populations that retreated to refugia in other parts of the world during the arid LGM. It is supported by evidence of comparatively mild climates and rich biota in south-central Beringia at this time (30,000-15,000 years ago). These and other developments suggest that the settlement of the Americas may be integrated with the global dispersal of modern humans.
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out of Beringia
Science, 2014Co-Authors: John F. Hoffecker, Scott A. Elias, Dennis H OrourkeAbstract:Based on the distribution of tundra plants around the Bering Strait region, Eric Hulten proposed in the 1930s that the now-submerged plain between Chukotka and Alaska—the Bering land bridge—became a refugium for shrub tundra vegetation during cold periods ( 1 ), which include the last glacial maximum (LGM) between ∼28,000 and 18,000 cal BP (calibrated radiocarbon years before the present). Adjoining areas to the west and east supported drier plant communities with a higher percentage of grasses during glacial periods. According to Hulten, when warmer and wetter conditions returned to these areas, the land bridge, which he named Beringia, became a center of dispersal for tundra plants. Now it appears that it also may have been a glacial refugium and postglacial center of dispersal for the people who first settled the Americas.
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paleoenvironmental reconstruction of the last glacial maximum inferred from insect fossils from a tephra buried soil at tempest lake seward peninsula alaska
Palaeogeography Palaeoclimatology Palaeoecology, 2008Co-Authors: Svetlana Kuzmina, Scott A. Elias, Paul Matheus, John Storer, Andrei SherAbstract:Abstract Sediments and vegetation dated 21,570 cal yr BP were buried under tephra on the northern Seward Peninsula. This buried surface has yielded plant macrofossils in growth position, as well as numerous insect fossils, excellently preserved in permafrost. It appears that many of the insects were buried alive by the volcanic ash. The species composition and ecological affinities of this fossil fauna are typical of Alaskan Late Pleistocene steppe–tundra environments. The assemblages are dominated by the weevil Lepidophorus lineaticollis , one of the most common species in Eastern Beringian Pleistocene fossil assemblages. Many other members of the ancient steppe–tundra insect community are preserved in these assemblages, including the pill beetle Morychus sp. and weevils of the genus Coniocleonus . In Alaska, most of these species (but not all of them) survived the Pleistocene/Holocene environmental transition, but are restricted today to relict patches of steppe-like vegetation. Faunal diversity is low, in spite of the recovery of more than 1000 individual insects and mites including more than 600 beetles. This reflects the small number of species adapted to the cold, dry environments of the LGM in Eastern Beringia. They represent an ecosystem which no longer exists.
Patricia M Anderson - One of the best experts on this subject based on the ideXlab platform.
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late quaternary environments on the far southwestern edge of Beringia
Quaternary Science Reviews, 2019Co-Authors: A V Lozhkin, Patricia M Anderson, Yu O Glushkova, L N VazheninaAbstract:Abstract Palynological and plant macrofossil data and remains of Mammuthus primigenius from the Tanon quarry (59° 40′ N, 151° 12′ E) provide much needed information about environments in southwestern Beringia during the Middle Holocene and marine isotope stages (MIS) 2 and 3. During the Middle Holocene, Larix-Betula forest characterized the Tanon region and differed from the Larix forests of interior Western Beringia. Betula platyphylla, which today is more common in moderate regions of the Far East, was an important component of the coastal forest near the quarry and possibly was more extensive in the coastal lowland. Ecological and quantitative models suggest that the coastal region experienced longer growing seasons and warmer summer temperatures, which could support the expansion of tree Betula. The MIS 2 palynological assemblage from Tanon indicates a prevalence of mesic and xeric herb-dominated tundra. However, the macrofossil data consist largely of taxa found in forest or forest-tundra with only a minor contribution by steppe species. The Tanon results agree with the larger paleovegetation database from Beringia, which suggests that steppe was not widespread during the Late Pleistocene but rather the landscape was characterized by a mosaic of tundra types. The Tanon site provides the first information about MIS 3 coastal vegetation, indicating the presence of Larix-Betula forest within valleys and shrub tundra at higher elevations. The discovery of Mammuthus primigenius in the quarry marks the southernmost population of Late Pleistocene mammoths in Western Beringia.
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eastern Beringia climates and environments during the initial peopling
2017Co-Authors: Patricia M Anderson, A V LozhkinAbstract:Abstract The majority of archaeological sites documenting the first human migration to the Eastern Beringia are located in three areas of Alaska: the central, northern, and southwestern parts. The prehistory of Beringia demonstrates that the earliest well-documented human wave of migrations was referred to the transitional period between the Late Pleistocene and the Holocene (from 12.5 to 9 14 C kyr BP). This time span has been characterized by rapid environmental changes in Beringia, connected with the rise of sea level, mountain deglaciation, and important changes in floral and faunal communities. Four main climatic phases could be identified. The first one was associated with the early postglacial climate amelioration that occurred between 12.5 and 11 14 C kyr BP. The second was the postglacial maximum followed by the Younger Dryas and subsequent Early Holocene cooling.
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western Beringia northeast asia
Human Colonization of the Arctic: The Interaction Between Early Migration and the Paleoenvironment, 2017Co-Authors: Sergey B Slobodin, Patricia M Anderson, Olga Glushkova, A V LozhkinAbstract:Abstract Archaeological and paleogeographic evidence suggests that Northeast Asia (Western Beringia) was a starting point from which prehistoric man began to explore the Western Hemisphere via the Bering Land Bridge. Current data suggest that the exploration by humans of the arctic zone of Western Beringia occurred no later than the second half of the Late Pleistocene, during the time span with favorable conditions for human dispersals. The Yana Site witnesses that at the end of the Karginsky, Paleolithic man almost reached the modern arctic coast at the Indigirka-Kolyma lowlands. Later, during the Sartan, some new complexes (cultures) appeared, represented by those sites as Khaya IV, Kheta, Druchak, Ushki I to V, etc. Changing landscapes and climates of Western Beringia in the Early Holocene provoked new developments and the disappearance of the Paleolithic cultures, which were replaced by the Mesolithic cultures more adapted to the new conditions.
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early holocene warming in Beringia and its mediation by sea level and vegetation changes
Climate of The Past, 2015Co-Authors: Patrick J Bartlein, Patricia M Anderson, Mary E Edwards, Linda B. Brubaker, Steven W Hostetler, Sarah L Shafer, A V LozhkinAbstract:Abstract. Arctic land-cover changes induced by recent global climate change (e.g., expansion of woody vegetation into tundra and effects of permafrost degradation) are expected to generate further feedbacks to the climate system. Past changes can be used to assess our understanding of feedback mechanisms through a combination of process modeling and paleo-observations. The subcontinental region of Beringia (northeastern Siberia, Alaska, and northwestern Canada) was largely ice-free at the peak of deglacial warming and experienced both major vegetation change and loss of permafrost when many arctic regions were still ice covered. The evolution of Beringian climate at this time was largely driven by global features, such as the amplified seasonal cycle of Northern Hemisphere insolation and changes in global ice volume and atmospheric composition, but changes in regional land-surface controls, such as the widespread development of thaw lakes, the replacement of tundra by deciduous forest or woodland, and the flooding of the Bering–Chukchi land bridge, were probably also important. We examined the sensitivity of Beringia's early Holocene climate to these regional-scale controls using a regional climate model (RegCM). Lateral and oceanic boundary conditions were provided by global climate simulations conducted using the GENESIS V2.01 atmospheric general circulation model (AGCM) with a mixed-layer ocean. We carried out two present-day simulations of regional climate – one with modern and one with 11 ka geography – plus another simulation for 6 ka. In addition, we performed five ~ 11 ka climate simulations, each driven by the same global AGCM boundary conditions: (i) 11 ka Control, which represents conditions just prior to the major transitions (exposed land bridge, no thaw lakes or wetlands, widespread tundra vegetation), (ii) sea-level rise, which employed present-day continental outlines, (iii) vegetation change, with deciduous needleleaf and deciduous broadleaf boreal vegetation types distributed as suggested by the paleoecological record, (iv) thaw lakes, which used the present-day distribution of lakes and wetlands, and (v) post-11 ka All, incorporating all boundary conditions changed in experiments (ii)–(iv). We find that regional-scale controls strongly mediate the climate responses to changes in the large-scale controls, amplifying them in some cases, damping them in others, and, overall, generating considerable spatial heterogeneity in the simulated climate changes. The change from tundra to deciduous woodland produces additional widespread warming in spring and early summer over that induced by the 11 ka insolation regime alone, and lakes and wetlands produce modest and localized cooling in summer and warming in winter. The greatest effect is the flooding of the land bridge and shelves, which produces generally cooler conditions in summer but warmer conditions in winter and is most clearly manifest on the flooded shelves and in eastern Beringia. By 6 ka continued amplification of the seasonal cycle of insolation and loss of the Laurentide ice sheet produce temperatures similar to or higher than those at 11 ka, plus a longer growing season.
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a re evaluation and spatial analysis of evidence for a younger dryas climatic reversal in Beringia
Quaternary Science Reviews, 2008Co-Authors: H D Kokorowski, Patricia M Anderson, Cary J Mock, A V LozhkinAbstract:Abstract An objective classification of paleoclimatic proxies from 75 lake and peat records is used to re-evaluate data quality and inferred climatic patterns in Beringia during the Younger Dryas. Mapped data reveal coherent but spatially-complex regional patterns, suggesting the Younger Dryas was characterized by: (1) cooling in Southern Alaska, Eastern Siberia, and portions of Northeastern Siberia; and (2) uniform to warmer-than-present conditions through most of Central Alaska, Northeastern Siberia, and possibly the Russian Far East and Northern Alaska. The Beringian patterns correspond to distinctive large-scale climatic forcings, although in some locations further modified by more local influences, such as topography. General circulation models and modern synoptic climatology provide a conceptual framework for exploring possible mechanisms responsible for the observed changes. Forcings and associated climatic responses consistent with the proxy data include: (1) lowered sea-surface temperatures in the North Atlantic and Pacific reducing temperature and precipitation in Eastern Siberia; (2) intensified Aleutian low and lowered sea-surface temperatures causing cooler summers and higher winter precipitation in Southern Alaska; (3) stronger Pacific Subtropical High and an eastward shift of the East Asian Trough reducing summer temperatures in Southern Alaska and causing relative warmth in Northeastern Siberia; and (4) strong high pressure system producing warm, dry conditions in interior Alaska.
Vadim B Fedorov - One of the best experts on this subject based on the ideXlab platform.
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phylogeography of a holarctic rodent myodes rutilus testing high latitude biogeographical hypotheses and the dynamics of range shifts
Journal of Biogeography, 2015Co-Authors: Brooks A Kohli, Vadim B Fedorov, Eric Waltari, Joseph A CookAbstract:Aim We used the Holarctic northern red-backed vole (Myodes rutilus) as a model organism to improve our understanding of how dynamic, northern high-latitude environments have affected the genetic diversity, demography and distribution of boreal organisms. We tested spatial and temporal hypotheses derived from previous mitochondrial studies, comparative phylogeography, palaeoecology and the fossil record regarding diversification of M. rutilus in the Palaearctic and Beringia. Location High-latitude biomes across the Holarctic. Methods We used a multilocus phylogeographical approach combined with species distribution models to characterize the biogeographical and demographic history of M. rutilus. Our molecular assessment included widespread sampling (more than 100 localities), species tree reconstruction and population genetic analyses. Results Three well-differentiated mitochondrial lineages correspond to geographical regions, but nuclear genes were less structured. Multilocus divergence estimates indicated that diversification of M. rutilus was driven by events occurring before c. 100 ka. Population expansion in all three clades occurred prior to the Last Glacial Maximum (LGM) and presumably led to secondary contact. Species distribution modelling predicted a broad LGM distribution consistent with population and range expansion during this period. Main conclusions The biogeographical history of M. rutilus differs from other boreal forest-associated species. Well-differentiated clades and the existence of secondary contact zones indicate prolonged isolation and persistence in Eurasian and Beringian refugia. Dynamic demographic and distributional changes emphasize the impact of pre-LGM glacial–interglacial cycles on contemporary geographical structure. The Bering Strait was not a significant factor in the diversification of northern red-backed voles.
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multiple glacial refugia in the north american arctic inference from phylogeography of the collared lemming dicrostonyx groenlandicus
Proceedings of The Royal Society B: Biological Sciences, 2002Co-Authors: Vadim B Fedorov, Nils Christian StensethAbstract:Cryptic northern refugia beyond the ice limit of the Pleistocene glaciations may have had significant influence on the current pattern of biodiversity in Arctic regions. In order to evaluate whether northern glacial refugia existed in the Canadian Arctic, we examined mitochondrial DNA phylogeography in the northernmost species of rodents, the collared lemming (Dicrostonyx groenlandicus) sampled across its range of distribution in the North American Arctic and Greenland. The division of the collared lemming into the Canadian Arctic and eastern Beringia phylogroups does not support postglacial colonization of the North American Arctic from a single eastern Beringia refugium. Rather, the phylogeographical structure and sparse fossil records indicate that, during the last glaciation, some biologically significant refugia and important sources of postglacial colonization were located to the northwest of the main ice sheet in the Canadian Arctic.
Hervé Bocherens - One of the best experts on this subject based on the ideXlab platform.
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thriving or surviving the isotopic record of the wrangel island woolly mammoth population
Quaternary Science Reviews, 2019Co-Authors: Laura Arppe, Dorothee G Drucker, Sergey Vartanyan, Juha A Karhu, Heli Etusihvola, Hervé BocherensAbstract:Abstract The world's last population of woolly mammoths (Mammuthus primigenius) lived on Wrangel Island persisting well into the Holocene, going extinct at ca. 4000 cal BP. According to the frequency of radiocarbon dated mammoth remains from the island, the extinction appears fairly abrupt. This study investigates the ecology of the Wrangel Island mammoth population by means of carbon, nitrogen and sulfur isotope analyses. We report new isotope data on 77 radiocarbon dated mammoth specimens from Wrangel Island and Siberia, and evaluate them in relation to previously published isotope data for Pleistocene mammoths from Beringia and lower latitude Eurasia, and the other insular Holocene mammoth population from St. Paul Island. Contrary to prior suggestions of gradual habitat deterioration, the nitrogen isotope values of the Wrangel Island mammoths do not support a decline in forage quality/quantity, and are in fact very similar to their north Beringian forebears right to the end. However, compared to Siberian mammoths, those from Wrangel Island show a difference in their energy economy as judged by the carbon isotope values of structural carbonate, possibly representing a lower need of adaptive strategies for survival in extreme cold. Increased mid-Holocene weathering of rock formations in the central mountains is suggested by sulfur isotope values. Scenarios related to water quality problems stemming from increased weathering, and a possibility of a catastrophic starvation event as a cause of, or contributing factor in their demise are discussed.
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thriving or surviving the isotopic record of the wrangel island woolly mammoth population
Quaternary Science Reviews, 2019Co-Authors: Laura Arppe, Dorothee G Drucker, Sergey Vartanyan, Juha A Karhu, Heli Etusihvola, Hervé BocherensAbstract:Abstract The world's last population of woolly mammoths (Mammuthus primigenius) lived on Wrangel Island persisting well into the Holocene, going extinct at ca. 4000 cal BP. According to the frequency of radiocarbon dated mammoth remains from the island, the extinction appears fairly abrupt. This study investigates the ecology of the Wrangel Island mammoth population by means of carbon, nitrogen and sulfur isotope analyses. We report new isotope data on 77 radiocarbon dated mammoth specimens from Wrangel Island and Siberia, and evaluate them in relation to previously published isotope data for Pleistocene mammoths from Beringia and lower latitude Eurasia, and the other insular Holocene mammoth population from St. Paul Island. Contrary to prior suggestions of gradual habitat deterioration, the nitrogen isotope values of the Wrangel Island mammoths do not support a decline in forage quality/quantity, and are in fact very similar to their north Beringian forebears right to the end. However, compared to Siberian mammoths, those from Wrangel Island show a difference in their energy economy as judged by the carbon isotope values of structural carbonate, possibly representing a lower need of adaptive strategies for survival in extreme cold. Increased mid-Holocene weathering of rock formations in the central mountains is suggested by sulfur isotope values. Scenarios related to water quality problems stemming from increased weathering, and a possibility of a catastrophic starvation event as a cause of, or contributing factor in their demise are discussed.
John F. Hoffecker - One of the best experts on this subject based on the ideXlab platform.
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arctic Beringia and native american origins
PaleoAmerica, 2020Co-Authors: John F. Hoffecker, Scott A. Elias, Olga PotapovaAbstract:The central lowland of Beringia (aka the Bering land bridge) has been viewed alternately as a barrier or a refugium to the Native American founder population during the Last Glacial Maximum (LGM). ...
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environmental selection during the last ice age on the mother to infant transmission of vitamin d and fatty acids through breast milk
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Leslea J Hlusko, John F. Hoffecker, Scott A. Elias, Joshua P Carlson, George Chaplin, Michaela Huffman, Nina G Jablonski, Tesla A Monson, Dennis H Orourke, Marin A PilloudAbstract:Because of the ubiquitous adaptability of our material culture, some human populations have occupied extreme environments that intensified selection on existing genomic variation. By 32,000 years ago, people were living in Arctic Beringia, and during the Last Glacial Maximum (LGM; 28,000–18,000 y ago), they likely persisted in the Beringian refugium. Such high latitudes provide only very low levels of UV radiation, and can thereby lead to dangerously low levels of biosynthesized vitamin D. The physiological effects of vitamin D deficiency range from reduced dietary absorption of calcium to a compromised immune system and modified adipose tissue function. The ectodysplasin A receptor ( EDAR ) gene has a range of pleiotropic effects, including sweat gland density, incisor shoveling, and mammary gland ductal branching. The frequency of the human-specific EDAR V370A allele appears to be uniquely elevated in North and East Asian and New World populations due to a bout of positive selection likely to have occurred circa 20,000 y ago. The dental pleiotropic effects of this allele suggest an even higher occurrence among indigenous people in the Western Hemisphere before European colonization. We hypothesize that selection on EDAR V370A occurred in the Beringian refugium because it increases mammary ductal branching, and thereby may amplify the transfer of critical nutrients in vitamin D-deficient conditions to infants via mothers’ milk. This hypothesized selective context for EDAR V370A was likely intertwined with selection on the fatty acid desaturase ( FADS ) gene cluster because it is known to modulate lipid profiles transmitted to milk from a vitamin D-rich diet high in omega-3 fatty acids.
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Beringia and the global dispersal of modern humans.
Evolutionary anthropology, 2016Co-Authors: John F. Hoffecker, Scott A. Elias, Dennis H. O'rourke, G. Richard Scott, Nancy H. BigelowAbstract:Until recently, the settlement of the Americas seemed largely divorced from the out-of-Africa dispersal of anatomically modern humans, which began at least 50,000 years ago. Native Americans were thought to represent a small subset of the Eurasian population that migrated to the Western Hemisphere less than 15,000 years ago. Archeological discoveries since 2000 reveal, however, that Homo sapiens occupied the high-latitude region between Northeast Asia and northwest North America (that is, Beringia) before 30,000 years ago and the Last Glacial Maximum (LGM). The settlement of Beringia now appears to have been part of modern human dispersal in northern Eurasia. A 2007 model, the Beringian Standstill Hypothesis, which is based on analysis of mitochondrial DNA (mtDNA) in living people, derives Native Americans from a population that occupied Beringia during the LGM. The model suggests a parallel between ancestral Native Americans and modern human populations that retreated to refugia in other parts of the world during the arid LGM. It is supported by evidence of comparatively mild climates and rich biota in south-central Beringia at this time (30,000-15,000 years ago). These and other developments suggest that the settlement of the Americas may be integrated with the global dispersal of modern humans.
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out of Beringia
Science, 2014Co-Authors: John F. Hoffecker, Scott A. Elias, Dennis H OrourkeAbstract:Based on the distribution of tundra plants around the Bering Strait region, Eric Hulten proposed in the 1930s that the now-submerged plain between Chukotka and Alaska—the Bering land bridge—became a refugium for shrub tundra vegetation during cold periods ( 1 ), which include the last glacial maximum (LGM) between ∼28,000 and 18,000 cal BP (calibrated radiocarbon years before the present). Adjoining areas to the west and east supported drier plant communities with a higher percentage of grasses during glacial periods. According to Hulten, when warmer and wetter conditions returned to these areas, the land bridge, which he named Beringia, became a center of dispersal for tundra plants. Now it appears that it also may have been a glacial refugium and postglacial center of dispersal for the people who first settled the Americas.
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human ecology of Beringia
2007Co-Authors: John F. Hoffecker, Scott A. EliasAbstract:Preface: Lost Continent1. An Introduction to Beringia2. Beringian Landscapes3. Settlement of Northern Asia4. The Beginning of the Lateglacial5. The End of the Lateglacial Interstadial6. The Younger Dryas and the End of Beringia7. Beringia and the New WorldNotesBibliographyIndex