The Experts below are selected from a list of 49416 Experts worldwide ranked by ideXlab platform
Oren Kolodny - One of the best experts on this subject based on the ideXlab platform.
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disease transmission and introgression can explain the long lasting contact zone of Modern Humans and neanderthals
Nature Communications, 2019Co-Authors: Gili Greenbaum, Wayne M Getz, Noah A Rosenberg, Marcus W Feldman, Erella Hovers, Oren KolodnyAbstract:Neanderthals and Modern Humans both occupied the Levant for tens of thousands of years prior to the spread of Modern Humans into the rest of Eurasia and their replacement of the Neanderthals. That the inter-species boundary remained geographically localized for so long is a puzzle, particularly in light of the rapidity of its subsequent movement. Here, we propose that infectious-disease dynamics can explain the localization and persistence of the inter-species boundary. We further propose, and support with dynamical-systems models, that introgression-based transmission of alleles related to the immune system would have gradually diminished this barrier to pervasive inter-species interaction, leading to the eventual release of the inter-species boundary from its geographic localization. Asymmetries between the species in the characteristics of their associated ‘pathogen packages’ could have generated feedback that allowed Modern Humans to overcome disease burden earlier than Neanderthals, giving them an advantage in their subsequent spread into Eurasia. Modern Humans and Neanderthals coexisted in the Levant for tens of thousands of years before Modern Humans spread and replaced Neanderthals. Here, Greenbaum et al. develop a model showing that transmission of disease and genes can explain the maintenance and then collapse of this contact zone.
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disease transmission and introgression can explain the long lasting contact zone of Modern Humans and neanderthals
Nature Communications, 2019Co-Authors: Gili Greenbaum, Wayne M Getz, Noah A Rosenberg, Marcus W Feldman, Erella Hovers, Oren KolodnyAbstract:Neanderthals and Modern Humans both occupied the Levant for tens of thousands of years prior to the spread of Modern Humans into the rest of Eurasia and their replacement of the Neanderthals. That the inter-species boundary remained geographically localized for so long is a puzzle, particularly in light of the rapidity of its subsequent movement. Here, we propose that infectious-disease dynamics can explain the localization and persistence of the inter-species boundary. We further propose, and support with dynamical-systems models, that introgression-based transmission of alleles related to the immune system would have gradually diminished this barrier to pervasive inter-species interaction, leading to the eventual release of the inter-species boundary from its geographic localization. Asymmetries between the species in the characteristics of their associated 'pathogen packages' could have generated feedback that allowed Modern Humans to overcome disease burden earlier than Neanderthals, giving them an advantage in their subsequent spread into Eurasia.
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was inter population connectivity of neanderthals and Modern Humans the driver of the upper paleolithic transition rather than its product
Quaternary Science Reviews, 2019Co-Authors: Gili Greenbaum, Marcus W Feldman, Erella Hovers, Oren Kolodny, David E FriesemAbstract:Abstract The transition from the Middle Paleolithic (MP) to the Upper Paleolithic (UP), circa 40kya, is viewed as a major turning point in human evolution, in terms of the material culture, demography, and geographical expansion of Modern Humans. However, attempts to identify an origin of this so-called ‘revolution’ in the form of a particular stone-tool techno-complex, representing cultural Modernity, which spread across the human range, have failed. Instead, the archaeological record of this period comprises multiple ‘transitional techno-complexes’, some associated with Modern Humans and others with Neanderthals. The cultures that these techno-complexes represent are characterized by precursors of the material cultures of the UP, often alongside features that suggest local cultural continuity. The broadly simultaneous appearance of these transitional cultures, despite a lack of a clear common origin, is puzzling. We suggest that these local ‘revolutions’ had a common underlying driver, which explains the simultaneous appearance of transitional techno-complexes, but that this driver did not determine the particular form of each local revolution. We propose that the driver of the transition to the UP was an increase in inter-population connectivity, both within- and between-species, which allowed local cultures to rapidly evolve and to attain greater complexity than ever before. We suggest that this change was driven by the interaction between Modern Humans and Neanderthals. In this article we outline processes that are likely to have influenced inter-population connectivity, bringing together evolutionary and ecological perspectives alongside insights from the field of cultural evolution.
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random drift with a determined outcome a parsimonious null model of neanderthal replacement by Modern Humans via neutral species drift
bioRxiv, 2017Co-Authors: Oren Kolodny, Marcus W FeldmanAbstract:The processes that led to the demise of the Neanderthals and their replacement by Modern Humans have been the object of heated debate. Most hypotheses fall into one of two categories: one highlights the role of climate change, epidemics, or other environmental pressures in the Neanderthals9 demise, and the other attributes it to direct or indirect competition with Modern Humans, who occupied the same ecological niche. The latter assume that Modern Humans benefited from some selective advantage over Neanderthals that led to the latter9s extinction. We show that a scenario of migration and selectively neutral species drift can explain the Neanderthals9 replacement. Our model offers a parsimonious alternative to those that invoke external factors or selective advantage, and represents a null hypothesis in assessing such alternatives. We show that for a wide range of parameters this hypothesis cannot be rejected. Moreover, we suggest that although selection and environmental factors may or may not have played a role in the interspecies dynamics of Neanderthals and Modern Humans, the eventual outcome, the replacement of the Neanderthals, was determined by the migration dynamics at the end of the middle Paleolithic, namely repeated migration of Modern Humans from Africa into the Levant and Europe.
Janet Kelso - One of the best experts on this subject based on the ideXlab platform.
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the contribution of neanderthals to phenotypic variation in Modern Humans
American Journal of Human Genetics, 2017Co-Authors: Michael Dannemann, Janet KelsoAbstract:Assessing the genetic contribution of Neanderthals to non-disease phenotypes in Modern Humans has been difficult because of the absence of large cohorts for which common phenotype information is available. Using baseline phenotypes collected for 112,000 individuals by the UK Biobank, we can now elaborate on previous findings that identified associations between signatures of positive selection on Neanderthal DNA and various Modern human traits but not any specific phenotypic consequences. Here, we show that Neanderthal DNA affects skin tone and hair color, height, sleeping patterns, mood, and smoking status in present-day Europeans. Interestingly, multiple Neanderthal alleles at different loci contribute to skin and hair color in present-day Europeans, and these Neanderthal alleles contribute to both lighter and darker skin tones and hair color, suggesting that Neanderthals themselves were most likely variable in these traits.
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Functional implications of Neandertal introgression in Modern Humans.
Genome biology, 2017Co-Authors: Michael Dannemann, Kay Prüfer, Janet KelsoAbstract:Admixture between early Modern Humans and Neandertals approximately 50,000–60,000 years ago has resulted in 1.5–4% Neandertal ancestry in the genomes of present-day non-Africans. Evidence is accumulating that some of these archaic alleles are advantageous for Modern Humans, while others are deleterious; however, the major mechanism by which these archaic alleles act has not been fully explored. Here we assess the contributions of introgressed non-synonymous and regulatory variants to Modern human protein and gene expression variation. We show that gene expression changes are more often associated with Neandertal ancestry than expected, and that the introgressed non-synonymous variants tend to have less predicted functional effect on Modern human proteins than mutations that arose on the human lineage. Conversely, introgressed alleles contribute proportionally more to expression variation than non-introgressed alleles. Our results suggest that the major influence of Neandertal introgressed alleles is through their effects on gene regulation.
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Functional implications of Neandertal introgression in Modern Humans
Genome Biology, 2017Co-Authors: Michael Dannemann, Kay Prüfer, Janet KelsoAbstract:Background Admixture between early Modern Humans and Neandertals approximately 50,000–60,000 years ago has resulted in 1.5–4% Neandertal ancestry in the genomes of present-day non-Africans. Evidence is accumulating that some of these archaic alleles are advantageous for Modern Humans, while others are deleterious; however, the major mechanism by which these archaic alleles act has not been fully explored. Results Here we assess the contributions of introgressed non-synonymous and regulatory variants to Modern human protein and gene expression variation. We show that gene expression changes are more often associated with Neandertal ancestry than expected, and that the introgressed non-synonymous variants tend to have less predicted functional effect on Modern human proteins than mutations that arose on the human lineage. Conversely, introgressed alleles contribute proportionally more to expression variation than non-introgressed alleles. Conclusions Our results suggest that the major influence of Neandertal introgressed alleles is through their effects on gene regulation.
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Ancient Humans and the origin of Modern Humans.
Current opinion in genetics & development, 2014Co-Authors: Janet Kelso, Kay PrüferAbstract:Recent advances in sequencing technologies and molecular methods have facilitated the sequencing of DNA from ancient human remains which has, in turn, provided unprecedented insight into human history. Within the past 4 years the genomes of Neandertals and Denisovans, as well as the genomes of at least two early Modern Humans, have been sequenced. These sequences showed that there have been several episodes of admixture between Modern and archaic groups; including admixture from Neandertals into Modern human populations outside of Africa, and admixture from Denisovans into Modern human populations in Oceania. Recent results indicate that some of these introgressed regions may have been advantageous for Modern Humans as they expanded into new regions outside of Africa.
John F. Hoffecker - One of the best experts on this subject based on the ideXlab platform.
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Technological complexity and the global dispersal of Modern Humans.
Evolutionary anthropology, 2017Co-Authors: John F. Hoffecker, Ian T. HoffeckerAbstract:Anatomically Modern Humans (Homo sapiens) dispersed out of Africa roughly 120,000 years ago and again after 75,000 years ago. The early dispersal was geographically restricted to the Arabian Peninsula, Levant, and possibly parts of southern Asia. The later dispersal was ultimately global in scope, including areas not previously occupied by Homo. One explanation for the contrast between the two out-of-Africa dispersals is that the Modern Humans who expanded into Eurasia 120,000 years ago lacked the functionally and structurally complex technology of recent hunter-gatherers. This technology, which includes, for example, mechanical projectiles, snares and traps, and sewn clothing, provides not only expanded dietary breadth and increased rates of foraging efficiency and success in places where plant and animal productivity is low, but protection from cold weather in places where winter temperatures are low. The absence of complex technology before 75,000 years ago also may explain why Modern Humans in the Levant did not develop sedentary settlements and agriculture 120,000 years ago (i.e., during the Last Interglacial).
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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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The spread of Modern Humans in Europe
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: John F. HoffeckerAbstract:The earliest credible evidence of Homo sapiens in Europe is an archaeological proxy in the form of several artifact assemblages (Bohunician) found in South-Central and possibly Eastern Europe, dating to ≤48,000 calibrated radiocarbon years before present (cal BP). They are similar to assemblages probably made by Modern Humans in the Levant (Emiran) at an earlier date and apparently represent a population movement into the Balkans during a warm climate interval [Greenland Interstadial 12 (GI 12)]. A second population movement may be represented by a diverse set of artifact assemblages (sometimes termed Proto-Aurignacian) found in the Balkans, parts of Southwest Europe, and probably in Eastern Europe, and dating to several brief interstadials (GI 11–GI 9) that preceded the beginning of cold Heinrich Event 4 (HE4) (≈40,000 cal BP). They are similar to contemporaneous assemblages made by Modern Humans in the Levant (Ahmarian). The earliest known human skeletal remains in Europe that may be unequivocally assigned to H. sapiens (Pecstera cu Oase, Romania) date to this time period (≈42,000 cal BP) but are not associated with artifacts. After the Campanian Ignimbrite volcanic eruption (40,000 cal BP) and the beginning of HE4, artifact assemblages assigned to the classic Aurignacian, an industry associated with Modern human skeletal remains that seems to have developed in Europe, spread throughout the continent.
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early upper paleolithic in eastern europe and implications for the dispersal of Modern Humans
Science, 2007Co-Authors: M V Anikovich, John F. Hoffecker, A A Sinitsyn, Vance T Holliday, Vasil V Popov, Sergey N Lisitsyn, Steven L Forman, G M Levkovskaya, G A Pospelova, I E KuzminaAbstract:Radiocarbon and optically stimulated luminescence dating and magnetic stratigraphy indicate Upper Paleolithic occupation-probably representing Modern Humans-at archaeological sites on the Don River in Russia 45,000 to 42,000 years ago. The oldest levels at Kostenki underlie a volcanic ash horizon identified as the Campanian Ignimbrite Y5 tephra that is dated elsewhere to about 40,000 years ago. The occupation layers contain bone and ivory artifacts, including possible figurative art, and fossil shells imported more than 500 kilometers. Thus, Modern Humans appeared on the central plain of Eastern Europe as early as anywhere else in northern Eurasia.
Erella Hovers - One of the best experts on this subject based on the ideXlab platform.
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disease transmission and introgression can explain the long lasting contact zone of Modern Humans and neanderthals
Nature Communications, 2019Co-Authors: Gili Greenbaum, Wayne M Getz, Noah A Rosenberg, Marcus W Feldman, Erella Hovers, Oren KolodnyAbstract:Neanderthals and Modern Humans both occupied the Levant for tens of thousands of years prior to the spread of Modern Humans into the rest of Eurasia and their replacement of the Neanderthals. That the inter-species boundary remained geographically localized for so long is a puzzle, particularly in light of the rapidity of its subsequent movement. Here, we propose that infectious-disease dynamics can explain the localization and persistence of the inter-species boundary. We further propose, and support with dynamical-systems models, that introgression-based transmission of alleles related to the immune system would have gradually diminished this barrier to pervasive inter-species interaction, leading to the eventual release of the inter-species boundary from its geographic localization. Asymmetries between the species in the characteristics of their associated ‘pathogen packages’ could have generated feedback that allowed Modern Humans to overcome disease burden earlier than Neanderthals, giving them an advantage in their subsequent spread into Eurasia. Modern Humans and Neanderthals coexisted in the Levant for tens of thousands of years before Modern Humans spread and replaced Neanderthals. Here, Greenbaum et al. develop a model showing that transmission of disease and genes can explain the maintenance and then collapse of this contact zone.
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disease transmission and introgression can explain the long lasting contact zone of Modern Humans and neanderthals
Nature Communications, 2019Co-Authors: Gili Greenbaum, Wayne M Getz, Noah A Rosenberg, Marcus W Feldman, Erella Hovers, Oren KolodnyAbstract:Neanderthals and Modern Humans both occupied the Levant for tens of thousands of years prior to the spread of Modern Humans into the rest of Eurasia and their replacement of the Neanderthals. That the inter-species boundary remained geographically localized for so long is a puzzle, particularly in light of the rapidity of its subsequent movement. Here, we propose that infectious-disease dynamics can explain the localization and persistence of the inter-species boundary. We further propose, and support with dynamical-systems models, that introgression-based transmission of alleles related to the immune system would have gradually diminished this barrier to pervasive inter-species interaction, leading to the eventual release of the inter-species boundary from its geographic localization. Asymmetries between the species in the characteristics of their associated 'pathogen packages' could have generated feedback that allowed Modern Humans to overcome disease burden earlier than Neanderthals, giving them an advantage in their subsequent spread into Eurasia.
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was inter population connectivity of neanderthals and Modern Humans the driver of the upper paleolithic transition rather than its product
Quaternary Science Reviews, 2019Co-Authors: Gili Greenbaum, Marcus W Feldman, Erella Hovers, Oren Kolodny, David E FriesemAbstract:Abstract The transition from the Middle Paleolithic (MP) to the Upper Paleolithic (UP), circa 40kya, is viewed as a major turning point in human evolution, in terms of the material culture, demography, and geographical expansion of Modern Humans. However, attempts to identify an origin of this so-called ‘revolution’ in the form of a particular stone-tool techno-complex, representing cultural Modernity, which spread across the human range, have failed. Instead, the archaeological record of this period comprises multiple ‘transitional techno-complexes’, some associated with Modern Humans and others with Neanderthals. The cultures that these techno-complexes represent are characterized by precursors of the material cultures of the UP, often alongside features that suggest local cultural continuity. The broadly simultaneous appearance of these transitional cultures, despite a lack of a clear common origin, is puzzling. We suggest that these local ‘revolutions’ had a common underlying driver, which explains the simultaneous appearance of transitional techno-complexes, but that this driver did not determine the particular form of each local revolution. We propose that the driver of the transition to the UP was an increase in inter-population connectivity, both within- and between-species, which allowed local cultures to rapidly evolve and to attain greater complexity than ever before. We suggest that this change was driven by the interaction between Modern Humans and Neanderthals. In this article we outline processes that are likely to have influenced inter-population connectivity, bringing together evolutionary and ecological perspectives alongside insights from the field of cultural evolution.
Svante Pääbo - One of the best experts on this subject based on the ideXlab platform.
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The Date of Interbreeding between Neandertals and Modern Humans
PLoS genetics, 2012Co-Authors: Sriram Sankararaman, Nick Patterson, Svante Pääbo, David ReichAbstract:Comparisons of DNA sequences between Neandertals and present-day Humans have shown that Neandertals share more genetic variants with non-Africans than with Africans. This could be due to interbreeding between Neandertals and Modern Humans when the two groups met subsequent to the emergence of Modern Humans outside Africa. However, it could also be due to population structure that antedates the origin of Neandertal ancestors in Africa. We measure the extent of linkage disequilibrium (LD) in the genomes of present-day Europeans and find that the last gene flow from Neandertals (or their relatives) into Europeans likely occurred 37,000–86,000 years before the present (BP), and most likely 47,000–65,000 years ago. This supports the recent interbreeding hypothesis and suggests that interbreeding may have occurred when Modern Humans carrying Upper Paleolithic technologies encountered Neandertals as they expanded out of Africa.
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No Evidence of Neandertal mtDNA Contribution to Early Modern Humans
PLoS biology, 2004Co-Authors: David Serre, André Langaney, Mario Chech, Maria Teschler-nicola, Maja Paunović, Philippe Mennecier, Michael Hofreiter, Göran Possnert, Svante PääboAbstract:The retrieval of mitochondrial DNA (mtDNA) sequences from four Neandertal fossils from Germany, Russia, and Croatia has demonstrated that these individuals carried closely related mtDNAs that are not found among current Humans. However, these results do not definitively resolve the question of a possible Neandertal contribution to the gene pool of Modern Humans since such a contribution might have been erased by genetic drift or by the continuous influx of Modern human DNA into the Neandertal gene pool. A further concern is that if some Neandertals carried mtDNA sequences similar to contemporaneous Humans, such sequences may be erroneously regarded as Modern contaminations when retrieved from fossils. Here we address these issues by the analysis of 24 Neandertal and 40 early Modern human remains. The biomolecular preservation of four Neandertals and of five early Modern Humans was good enough to suggest the preservation of DNA. All four Neandertals yielded mtDNA sequences similar to those previously determined from Neandertal individuals, whereas none of the five early Modern Humans contained such mtDNA sequences. In combination with current mtDNA data, this excludes any large genetic contribution by Neandertals to early Modern Humans, but does not rule out the possibility of a smaller contribution.
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Neandertal DNA Sequences and the Origin of Modern Humans
Cell, 1997Co-Authors: Matthias Krings, Anne C. Stone, Ralf W. Schmitz, Heike Krainitzki, Mark Stoneking, Svante PääboAbstract:DNA was extracted from the Neandertal-type specimen found in 1856 in western Germany. By sequencing clones from short overlapping PCR products, a hitherto unknown mitochondrial (mt) DNA sequence was determined. Multiple controls indicate that this sequence is endogenous to the fossil. Sequence comparisons with human mtDNA sequences, as well as phylogenetic analyses, show that the Neandertal sequence falls outside the variation of Modern Humans. Furthermore, the age of the common ancestor of the Neandertal and Modern human mtDNAs is estimated to be four times greater than that of the common ancestor of human mtDNAs. This suggests that Neandertals went extinct without contributing mtDNA to Modern Humans.
