Fascinating if true.
Mediterranean Archaeology and Archaeometry, Vol. 17, No 1, (2017), pp. 233-250
DECODING GÖBEKLI TEPE
WITH ARCHAEOASTRONOMY:
WHAT DOES THE FOX SAY?
Martin B. Sweatman* and Dimitrios Tsikritsis
We have interpreted much of the symbolism of Göbekli Tepe in terms of astronomical events. By matching
low-relief carvings on some of the pillars at Göbekli Tepe to star asterisms we find compelling evidence that
the famous ‘Vulture Stone’ is a date stamp for 10950 BC ± 250 yrs, which corresponds closely to the
proposed Younger Dryas event, estimated at 10890 BC. We also find evidence that a key function of Göbekli
Tepe was to observe meteor showers and record cometary encounters. Indeed, the people of Göbekli Tepe
appear to have had a special interest in the Taurid meteor stream, the same meteor stream that is proposed
as responsible for the Younger-Dryas event. Is Göbekli Tepe the ‘smoking gun’ for the Younger-Dryas
cometary encounter, and hence for coherent catastrophism?
Link (pdf)
Showing posts with label Climate. Show all posts
Showing posts with label Climate. Show all posts
April 21, 2017
May 02, 2016
Neandertal ancestry, going, going, ..., gone (?)
A deluge of new data from Upper Paleolithic Europe will give us all a lot to think about. It is incredible that Neandertal ancestry seems to have decreased over time in Europe (Oase1 is off-cline with lots of extra Neandertal ancestry from a recent genealogical Neandertal in the family tree). The functional form of the decrease seems pretty well approximated as linear.
The authors write:
As a corollary, there may have been other episodes of archaic admixture that are no longer detectable. Perhaps our modern human lineage has repeatedly admixed with other species, but traces of those admixtures are long gone by the action of natural selection. The reason for our relative homogeneity as a species may not be that we avoided intermixing with others, but that, sadly, most others had not much that was beneficial to offer to our ancestors.
Nature (2016) doi:10.1038/nature17993
The genetic history of Ice Age Europe
Qiaomei Fu et al.
Modern humans arrived in Europe ~45,000 years ago, but little is known about their genetic composition before the start of farming ~8,500 years ago. Here we analyse genome-wide data from 51 Eurasians from ~45,000–7,000 years ago. Over this time, the proportion of Neanderthal DNA decreased from 3–6% to around 2%, consistent with natural selection against Neanderthal variants in modern humans. Whereas there is no evidence of the earliest modern humans in Europe contributing to the genetic composition of present-day Europeans, all individuals between ~37,000 and ~14,000 years ago descended from a single founder population which forms part of the ancestry of present-day Europeans. An ~35,000-year-old individual from northwest Europe represents an early branch of this founder population which was then displaced across a broad region, before reappearing in southwest Europe at the height of the last Ice Age ~19,000 years ago. During the major warming period after ~14,000 years ago, a genetic component related to present-day Near Easterners became widespread in Europe. These results document how population turnover and migration have been recurring themes of European prehistory.
Link
The authors write:
Using one statistic, we estimate a decline from 4.3–5.7% from a time shortly after introgression to 1.1–2.2% in Eurasians today (Fig. 2).This is remarkable because it shows that most of the Neandertal ancestry of the earliest AMH in Europe was gone by the Mesolithic. It really seems that Neandertal genes were bred out of the gene pool over time. Will this trend continue into the future? Perhaps only minute traces of Neandertal DNA will remain in humans in 10,000 more years. Some of Neandertal DNA may yet prove to be neutral or beneficial, so at the limit the percentage may be more than zero. Nonetheless, the historical trend does suggest that modern humans inherited mostly genetic garbage from Neandertals and evolution is more than halfway through the process of getting rid of it.
As a corollary, there may have been other episodes of archaic admixture that are no longer detectable. Perhaps our modern human lineage has repeatedly admixed with other species, but traces of those admixtures are long gone by the action of natural selection. The reason for our relative homogeneity as a species may not be that we avoided intermixing with others, but that, sadly, most others had not much that was beneficial to offer to our ancestors.
Nature (2016) doi:10.1038/nature17993
The genetic history of Ice Age Europe
Qiaomei Fu et al.
Modern humans arrived in Europe ~45,000 years ago, but little is known about their genetic composition before the start of farming ~8,500 years ago. Here we analyse genome-wide data from 51 Eurasians from ~45,000–7,000 years ago. Over this time, the proportion of Neanderthal DNA decreased from 3–6% to around 2%, consistent with natural selection against Neanderthal variants in modern humans. Whereas there is no evidence of the earliest modern humans in Europe contributing to the genetic composition of present-day Europeans, all individuals between ~37,000 and ~14,000 years ago descended from a single founder population which forms part of the ancestry of present-day Europeans. An ~35,000-year-old individual from northwest Europe represents an early branch of this founder population which was then displaced across a broad region, before reappearing in southwest Europe at the height of the last Ice Age ~19,000 years ago. During the major warming period after ~14,000 years ago, a genetic component related to present-day Near Easterners became widespread in Europe. These results document how population turnover and migration have been recurring themes of European prehistory.
Link
June 11, 2014
Craniometric discontinuity at the Last Glacial Maximum in Europe
The paper includes a craniometric dataset on 10 variables in the supplementary material.
Nature Communications 5, Article number: 4094 doi:10.1038/ncomms5094
Craniometric analysis of European Upper Palaeolithic and Mesolithic samples supports discontinuity at the Last Glacial Maximum
Ciaraán Brewster et al.
The Last Glacial Maximum (LGM) represents the most significant climatic event since the emergence of anatomically modern humans (AMH). In Europe, the LGM may have played a role in changing morphological features as a result of adaptive and stochastic processes. We use craniometric data to examine morphological diversity in pre- and post-LGM specimens. Craniometric variation is assessed across four periods—pre-LGM, late glacial, Early Holocene and Middle Holocene—using a large, well-dated, data set. Our results show significant differences across the four periods, using a MANOVA on size-adjusted cranial measurements. A discriminant function analysis shows separation between pre-LGM and later groups. Analyses repeated on a subsample, controlled for time and location, yield similar results. The results are largely influenced by facial measurements and are most consistent with neutral demographic processes. These findings suggest that the LGM had a major impact on AMH populations in Europe prior to the Neolithic.
Link
Nature Communications 5, Article number: 4094 doi:10.1038/ncomms5094
Craniometric analysis of European Upper Palaeolithic and Mesolithic samples supports discontinuity at the Last Glacial Maximum
Ciaraán Brewster et al.
The Last Glacial Maximum (LGM) represents the most significant climatic event since the emergence of anatomically modern humans (AMH). In Europe, the LGM may have played a role in changing morphological features as a result of adaptive and stochastic processes. We use craniometric data to examine morphological diversity in pre- and post-LGM specimens. Craniometric variation is assessed across four periods—pre-LGM, late glacial, Early Holocene and Middle Holocene—using a large, well-dated, data set. Our results show significant differences across the four periods, using a MANOVA on size-adjusted cranial measurements. A discriminant function analysis shows separation between pre-LGM and later groups. Analyses repeated on a subsample, controlled for time and location, yield similar results. The results are largely influenced by facial measurements and are most consistent with neutral demographic processes. These findings suggest that the LGM had a major impact on AMH populations in Europe prior to the Neolithic.
Link
May 14, 2014
Younger Dryas/Cosmic Impact synchrony questioned
Good coverage in Nature News:
Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago
David J. Meltzer et al.
A key element underpinning the controversial hypothesis of a widely destructive extraterrestrial impact at the onset of the Younger Dryas is the claim that 29 sites across four continents yield impact indicators all dated to 12,800 ± 150 years ago. This claim can be rejected: only three of those sites are dated to this window of time. At the remainder, the supposed impact markers are undated or significantly older or younger than 12,800 years ago. Either there were many more impacts than supposed, including one as recently as 5 centuries ago, or, far more likely, these are not extraterrestrial impact markers.
Link
Supporters of the impact theory have put forth 29 sites, from North America to Europe and beyond, that contain a thin layer of sediments said to date to the start of the cosmic impact event. The latest study checked to see whether those sites were all really 12,800 years old.
Only 3 of the 29 are, the researchers report today in the Proceedings of the National Academy of Sciences1. The other sites either have not been dated using the usual radiometric methods, or are much older or younger than the reported impact. “The chronology doesn’t hold up,” says team leader David Meltzer, an archaeologist at Southern Methodist University in Dallas, Texas.but:
Impact supporters are not about to give up. “Meltzer’s analysis of the dates is overly simplistic and clearly biased towards his conclusions,” says Richard Firestone, a nuclear chemist at Lawrence Berkeley National Laboratory in California and leader of the impact theory. Errors in radiocarbon dating mean that not all of the sites will date precisely to 12,800 years ago, Firestone argues. And much of his team's argument relies on cross-correlating various sites containing impact markers, some with good radiocarbon dates and some without.PNAS doi: 10.1073/pnas.1401150111
Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago
David J. Meltzer et al.
A key element underpinning the controversial hypothesis of a widely destructive extraterrestrial impact at the onset of the Younger Dryas is the claim that 29 sites across four continents yield impact indicators all dated to 12,800 ± 150 years ago. This claim can be rejected: only three of those sites are dated to this window of time. At the remainder, the supposed impact markers are undated or significantly older or younger than 12,800 years ago. Either there were many more impacts than supposed, including one as recently as 5 centuries ago, or, far more likely, these are not extraterrestrial impact markers.
Link
February 28, 2014
4.2 kiloyear event and the demise of Indus Valley megacities
From the paper:
Geology doi: 10.1130/G35236.1
Abrupt weakening of the summer monsoon in northwest India ∼4100 yr ago
Yama Dixit et al.
Climate change has been suggested as a possible cause for the decline of urban centers of the Indus Civilization ∼4000 yr ago, but extant paleoclimatic evidence has been derived from locations well outside the distribution of Indus settlements. Here we report an oxygen isotope record of gastropod aragonite (δ18Oa) from Holocene sediments of paleolake Kotla Dahar (Haryana, India), which is adjacent to Indus settlements and documents Indian summer monsoon (ISM) variability for the past 6.5 k.y. A 4‰ increase in δ18Oa occurred at ca. 4.1 ka marking a peak in the evaporation/precipitation ratio in the lake catchment related to weakening of the ISM. Although dating uncertainty exists in both climate and archaeological records, the drought event 4.1 ka on the northwestern Indian plains is within the radiocarbon age range for the beginning of Indus de-urbanization, suggesting that climate may have played a role in the Indus cultural transformation.
Link
The 4.2 ka aridification event is regarded as one of the most severe climatic changes in the Holocene, and affected several Early Bronze Age populations from the Aegean to the ancient Near East (Cullen et al., 2000; Weiss and Brad- ley, 2001). This study demonstrates that the cli- mate changes at that time extended to the plains of northwestern India. The Kotla Dahar record alone cannot fully explain the role of climate change in the cultural evolution of the Indus civilization. The Indus settlements spanned a diverse range of environmental and ecological zones (Wright, 2010; Petrie, 2013); therefore, correlation of evidence for climate change and the decline of Indus urbanism requires a comprehensive assessment of the relationship between settlement and climate across a sub- stantial area (Weiss and Bradley, 2001; Petrie, 2013). The impact of the abrupt climate event in India and West Asia records, and that observed at Kotla Dahar, on settled life in the Indus region warrants further investigation.Plato (or rather the Egyptian priest speaking through Plato) may have been the first one to note the differential survival of people as a result of natural catastrophes. It is hard to imagine that such an extreme event would not unbalance agricultural economies leading to famine and also endanger the supply systems on which early cities were based. The failure of cities would in turn lead to a failure of governing elites centered on them and a power vacuum which new elites (armed with bronze weapons at this time) might take advantage of. Climate may have ended the Bronze Age civilization itself 1000 years later.
Geology doi: 10.1130/G35236.1
Abrupt weakening of the summer monsoon in northwest India ∼4100 yr ago
Yama Dixit et al.
Climate change has been suggested as a possible cause for the decline of urban centers of the Indus Civilization ∼4000 yr ago, but extant paleoclimatic evidence has been derived from locations well outside the distribution of Indus settlements. Here we report an oxygen isotope record of gastropod aragonite (δ18Oa) from Holocene sediments of paleolake Kotla Dahar (Haryana, India), which is adjacent to Indus settlements and documents Indian summer monsoon (ISM) variability for the past 6.5 k.y. A 4‰ increase in δ18Oa occurred at ca. 4.1 ka marking a peak in the evaporation/precipitation ratio in the lake catchment related to weakening of the ISM. Although dating uncertainty exists in both climate and archaeological records, the drought event 4.1 ka on the northwestern Indian plains is within the radiocarbon age range for the beginning of Indus de-urbanization, suggesting that climate may have played a role in the Indus cultural transformation.
Link
October 01, 2013
Neolithic boom followed by later collapse (Shennan et al. 2013)
From the paper:
Nature Communications 4, Article number: 2486 doi:10.1038/ncomms3486
Regional population collapse followed initial agriculture booms in mid-Holocene Europe
Stephen Shennan et al.
Following its initial arrival in SE Europe 8,500 years ago agriculture spread throughout the continent, changing food production and consumption patterns and increasing population densities. Here we show that, in contrast to the steady population growth usually assumed, the introduction of agriculture into Europe was followed by a boom-and-bust pattern in the density of regional populations. We demonstrate that summed calibrated radiocarbon date distributions and simulation can be used to test the significance of these demographic booms and busts in the context of uncertainty in the radiocarbon date calibration curve and archaeological sampling. We report these results for Central and Northwest Europe between 8,000 and 4,000 cal. BP and investigate the relationship between these patterns and climate. However, we find no evidence to support a relationship. Our results thus suggest that the demographic patterns may have arisen from endogenous causes, although this remains speculative.
Link
It is particularly important to note that the bust following the initial farming boom is found in two historically separate agricultural expansions, the first into Central Europe c. 7,500 years ago and the second into Northwest Europe 1,500 years later. It is possible that some of these regional declines represent out-migration to neighbouring areas rather than a real decline in numbers, for example, from the Paris Basin into Britain, but, in some cases, for example, Ireland, Scotland and Wessex, it is very clear that the rising and falling trends are roughly synchronous with one another—there is little indication of one going up as the others go down. On present evidence the decline in the initially raised population levels following the introduction of agriculture does not seem to be climate-related, but of course this still leaves open a variety of possible causes that remain to be explored in the future. One possibility is disease, as the reference to the Black Death above implies, although this would have to be occurring on multiple occasions at different times in different places, given the patterns shown. It is perhaps more likely that it arose from endogenous causes; for example, rapid population growth driven by farming to unsustainable levels, soil depletion or erosion arising from early farming practices, or simply the risk arising from relying on a small number of exploitable species32. However, these suggestions remain speculative and an autocorrelation analysis of the demographic data did not find evidence of a cyclical pattern, which would be one indicator of the operation of endogenous processes (Supplementary Fig. S7). Regardless of the cause, collapsing Neolithic populations must have had a major impact on social, economic and cultural processes.
Nature Communications 4, Article number: 2486 doi:10.1038/ncomms3486
Regional population collapse followed initial agriculture booms in mid-Holocene Europe
Stephen Shennan et al.
Following its initial arrival in SE Europe 8,500 years ago agriculture spread throughout the continent, changing food production and consumption patterns and increasing population densities. Here we show that, in contrast to the steady population growth usually assumed, the introduction of agriculture into Europe was followed by a boom-and-bust pattern in the density of regional populations. We demonstrate that summed calibrated radiocarbon date distributions and simulation can be used to test the significance of these demographic booms and busts in the context of uncertainty in the radiocarbon date calibration curve and archaeological sampling. We report these results for Central and Northwest Europe between 8,000 and 4,000 cal. BP and investigate the relationship between these patterns and climate. However, we find no evidence to support a relationship. Our results thus suggest that the demographic patterns may have arisen from endogenous causes, although this remains speculative.
Link
August 15, 2013
Climate caused the Late Bronze Age collapse in the Eastern Mediterranean
PLoS ONE 8(8): e71004. doi:10.1371/journal.pone.0071004
Environmental Roots of the Late Bronze Age Crisis
David Kaniewski et al.
The Late Bronze Age world of the Eastern Mediterranean, a rich linkage of Aegean, Egyptian, Syro-Palestinian, and Hittite civilizations, collapsed famously 3200 years ago and has remained one of the mysteries of the ancient world since the event’s retrieval began in the late 19th century AD/CE. Iconic Egyptian bas-reliefs and graphic hieroglyphic and cuneiform texts portray the proximate cause of the collapse as the invasions of the “Peoples-of-the-Sea” at the Nile Delta, the Turkish coast, and down into the heartlands of Syria and Palestine where armies clashed, famine-ravaged cities abandoned, and countrysides depopulated. Here we report palaeoclimate data from Cyprus for the Late Bronze Age crisis, alongside a radiocarbon-based chronology integrating both archaeological and palaeoclimate proxies, which reveal the effects of abrupt climate change-driven famine and causal linkage with the Sea People invasions in Cyprus and Syria. The statistical analysis of proximate and ultimate features of the sequential collapse reveals the relationships of climate-driven famine, sea-borne-invasion, region-wide warfare, and politico-economic collapse, in whose wake new societies and new ideologies were created.
Link
Environmental Roots of the Late Bronze Age Crisis
David Kaniewski et al.
The Late Bronze Age world of the Eastern Mediterranean, a rich linkage of Aegean, Egyptian, Syro-Palestinian, and Hittite civilizations, collapsed famously 3200 years ago and has remained one of the mysteries of the ancient world since the event’s retrieval began in the late 19th century AD/CE. Iconic Egyptian bas-reliefs and graphic hieroglyphic and cuneiform texts portray the proximate cause of the collapse as the invasions of the “Peoples-of-the-Sea” at the Nile Delta, the Turkish coast, and down into the heartlands of Syria and Palestine where armies clashed, famine-ravaged cities abandoned, and countrysides depopulated. Here we report palaeoclimate data from Cyprus for the Late Bronze Age crisis, alongside a radiocarbon-based chronology integrating both archaeological and palaeoclimate proxies, which reveal the effects of abrupt climate change-driven famine and causal linkage with the Sea People invasions in Cyprus and Syria. The statistical analysis of proximate and ultimate features of the sequential collapse reveals the relationships of climate-driven famine, sea-borne-invasion, region-wide warfare, and politico-economic collapse, in whose wake new societies and new ideologies were created.
Link
July 15, 2013
Early European farmers used manure
PNAS doi: 10.1073/pnas.1305918110
Crop manuring and intensive land management by Europe’s first farmers
Amy Bogaard et al.
The spread of farming from western Asia to Europe had profound long-term social and ecological impacts, but identification of the specific nature of Neolithic land management practices and the dietary contribution of early crops has been problematic. Here, we present previously undescribed stable isotope determinations of charred cereals and pulses from 13 Neolithic sites across Europe (dating ca. 5900–2400 cal B.C.), which show that early farmers used livestock manure and water management to enhance crop yields. Intensive manuring inextricably linked plant cultivation and animal herding and contributed to the remarkable resilience of these combined practices across diverse climatic zones. Critically, our findings suggest that commonly applied paleodietary interpretations of human and herbivore δ15N values have systematically underestimated the contribution of crop-derived protein to early farmer diets.
Link
Crop manuring and intensive land management by Europe’s first farmers
Amy Bogaard et al.
The spread of farming from western Asia to Europe had profound long-term social and ecological impacts, but identification of the specific nature of Neolithic land management practices and the dietary contribution of early crops has been problematic. Here, we present previously undescribed stable isotope determinations of charred cereals and pulses from 13 Neolithic sites across Europe (dating ca. 5900–2400 cal B.C.), which show that early farmers used livestock manure and water management to enhance crop yields. Intensive manuring inextricably linked plant cultivation and animal herding and contributed to the remarkable resilience of these combined practices across diverse climatic zones. Critically, our findings suggest that commonly applied paleodietary interpretations of human and herbivore δ15N values have systematically underestimated the contribution of crop-derived protein to early farmer diets.
Link
July 12, 2013
A Middle Paleolithic link between North Africa and the Thar desert
One more piece of evidence against the idea that modern humans expanded Out-of-Africa because of the technological/behavioral revolution evidenced during the Upper Paleolithic/Late Stone Age.
And, one more piece of evidence against the idea that early modern humans in Eurasia died out and were replaced wholesale circa 50-60 thousand years ago from a fresh OoA impulse. It would have been possible to suppose such a thing if the evidence for MP African influence was minor or geographically localized, but much more difficult when it extends over a wide region.
Of course, the attribution of the Katoati assemblages to modern humans is done indirectly by linking them to MSA sites of the Sahara, but the proliferation of real archaeological sites (see map) that can be linked to OoA makes it difficult to adopt the idea of an archaeologically invisible late OoA that (somehow) replaced all previous inhabitants.
Quaternary Science Reviews Available online 5 July 2013
Middle Palaeolithic occupation in the Thar Desert during the Upper Pleistocene: the signature of a modern human exit out of Africa?
James Blinkhorn et al.
The Thar Desert marks the transition from the Saharo-Arabian deserts to the Oriental biogeographical zone and is therefore an important location in understanding hominin occupation and dispersal during the Upper Pleistocene. Here, we report the discovery of stratified Middle Palaeolithic assemblages at Katoati in the north-eastern Thar Desert, dating to Marine Isotope Stages (MIS) 5 and the MIS 4–3 boundary, during periods of enhanced humidity. Hominins procured cobbles from gravels at the site as evidenced by early stages of stone tool reduction, with a component of more formalised point production. The MIS 5c assemblages at Katoati represent the earliest securely dated Middle Palaeolithic occupation of South Asia. Distinctive artefacts identified in both MIS 5 and MIS 4–3 boundary horizons match technological entities observed in Middle Palaeolithic assemblages in South Asia, Arabia and Middle Stone Age sites in the Sahara. The evidence from Katoati is consistent with arguments for the dispersal of Homo sapiens populations from Africa across southern Asia using Middle Palaeolithic technologies.
Link
And, one more piece of evidence against the idea that early modern humans in Eurasia died out and were replaced wholesale circa 50-60 thousand years ago from a fresh OoA impulse. It would have been possible to suppose such a thing if the evidence for MP African influence was minor or geographically localized, but much more difficult when it extends over a wide region.
Of course, the attribution of the Katoati assemblages to modern humans is done indirectly by linking them to MSA sites of the Sahara, but the proliferation of real archaeological sites (see map) that can be linked to OoA makes it difficult to adopt the idea of an archaeologically invisible late OoA that (somehow) replaced all previous inhabitants.
Quaternary Science Reviews Available online 5 July 2013
Middle Palaeolithic occupation in the Thar Desert during the Upper Pleistocene: the signature of a modern human exit out of Africa?
James Blinkhorn et al.
The Thar Desert marks the transition from the Saharo-Arabian deserts to the Oriental biogeographical zone and is therefore an important location in understanding hominin occupation and dispersal during the Upper Pleistocene. Here, we report the discovery of stratified Middle Palaeolithic assemblages at Katoati in the north-eastern Thar Desert, dating to Marine Isotope Stages (MIS) 5 and the MIS 4–3 boundary, during periods of enhanced humidity. Hominins procured cobbles from gravels at the site as evidenced by early stages of stone tool reduction, with a component of more formalised point production. The MIS 5c assemblages at Katoati represent the earliest securely dated Middle Palaeolithic occupation of South Asia. Distinctive artefacts identified in both MIS 5 and MIS 4–3 boundary horizons match technological entities observed in Middle Palaeolithic assemblages in South Asia, Arabia and Middle Stone Age sites in the Sahara. The evidence from Katoati is consistent with arguments for the dispersal of Homo sapiens populations from Africa across southern Asia using Middle Palaeolithic technologies.
Link
June 26, 2013
700,000-year old horse sequenced
A 700.000 year old horse gets its genome sequenced
Nature (2013) doi:10.1038/nature12323
Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse
Ludovic Orlando et al.
The rich fossil record of equids has made them a model for evolutionary processes1. Here we present a 1.12-times coverage draft genome from a horse bone recovered from permafrost dated to approximately 560–780 thousand years before present (kyr BP)2, 3. Our data represent the oldest full genome sequence determined so far by almost an order of magnitude. For comparison, we sequenced the genome of a Late Pleistocene horse (43?kyr BP), and modern genomes of five domestic horse breeds (Equus ferus caballus), a Przewalski’s horse (E. f. przewalskii) and a donkey (E. asinus). Our analyses suggest that the Equus lineage giving rise to all contemporary horses, zebras and donkeys originated 4.0–4.5?million years before present (Myr BP), twice the conventionally accepted time to the most recent common ancestor of the genus Equus4, 5. We also find that horse population size fluctuated multiple times over the past 2?Myr, particularly during periods of severe climatic changes. We estimate that the Przewalski’s and domestic horse populations diverged 38–72?kyr BP, and find no evidence of recent admixture between the domestic horse breeds and the Przewalski’s horse investigated. This supports the contention that Przewalski’s horses represent the last surviving wild horse population6. We find similar levels of genetic variation among Przewalski’s and domestic populations, indicating that the former are genetically viable and worthy of conservation efforts. We also find evidence for continuous selection on the immune system and olfaction throughout horse evolution. Finally, we identify 29 genomic regions among horse breeds that deviate from neutrality and show low levels of genetic variation compared to the Przewalski’s horse. Such regions could correspond to loci selected early during domestication.
Link
It is nothing short of a world record in DNA research that scientists at the Centre for GeoGenetics at the Natural History Museum of Denmark (University of Copenhagen) have hit. They have sequenced the so far oldest genome from a prehistoric creature. They have done so by sequencing and analyzing short pieces of DNA molecules preserved in bone-remnants from a horse that had been kept frozen for the last 700.000 years in the permafrost of Yukon, Canada. By tracking the genomic changes that transformed prehistoric wild horses into domestic breeds, the researchers have revealed the genetic make-up of modern horses with unprecedented details. The spectacular results are now published in the international scientific journal Nature.
...
First, by comparing the genome in the 700,000 year old horse with the genome of a 43,000 year old horse, six present day horses and the donkey the researchers could estimate how fast mutations accumulate through time and calibrate a genome-wide mutation rate. This revealed that the last common ancestor of all modern equids was living about 4.0-4.5 million years ago. Therefore, the evolutionary radiation underlying the origin of horses, donkeys and zebras reaches back in time twice as long as previously thought. Additionally, this new clock revealed multiple episodes of severe demographic fluctuation in horse history, in phase with major climatic changes such as the Last Glacial Maximum, some 20,000 years ago.I'll add the paper abstract later.
Nature (2013) doi:10.1038/nature12323
Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse
Ludovic Orlando et al.
The rich fossil record of equids has made them a model for evolutionary processes1. Here we present a 1.12-times coverage draft genome from a horse bone recovered from permafrost dated to approximately 560–780 thousand years before present (kyr BP)2, 3. Our data represent the oldest full genome sequence determined so far by almost an order of magnitude. For comparison, we sequenced the genome of a Late Pleistocene horse (43?kyr BP), and modern genomes of five domestic horse breeds (Equus ferus caballus), a Przewalski’s horse (E. f. przewalskii) and a donkey (E. asinus). Our analyses suggest that the Equus lineage giving rise to all contemporary horses, zebras and donkeys originated 4.0–4.5?million years before present (Myr BP), twice the conventionally accepted time to the most recent common ancestor of the genus Equus4, 5. We also find that horse population size fluctuated multiple times over the past 2?Myr, particularly during periods of severe climatic changes. We estimate that the Przewalski’s and domestic horse populations diverged 38–72?kyr BP, and find no evidence of recent admixture between the domestic horse breeds and the Przewalski’s horse investigated. This supports the contention that Przewalski’s horses represent the last surviving wild horse population6. We find similar levels of genetic variation among Przewalski’s and domestic populations, indicating that the former are genetically viable and worthy of conservation efforts. We also find evidence for continuous selection on the immune system and olfaction throughout horse evolution. Finally, we identify 29 genomic regions among horse breeds that deviate from neutrality and show low levels of genetic variation compared to the Przewalski’s horse. Such regions could correspond to loci selected early during domestication.
Link
May 21, 2013
Cosmic impact event ~12.8kya caused the Younger Dryas
PNAS doi: 10.1073/pnas.1301760110
Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago
James H. Wittke et al.
Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently confirmed in eight studies, but unconfirmed in two others, resulting in continued dispute about their occurrence, distribution, and origin. To further address this dispute and better identify YDB spherules, we present results from one of the largest spherule investigations ever undertaken regarding spherule geochemistry, morphologies, origins, and processes of formation. We investigated 18 sites across North America, Europe, and the Middle East, performing nearly 700 analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analyses and scanning electron microscopy for surface microstructural characterization. Twelve locations rank among the world’s premier end-Pleistocene archaeological sites, where the YDB marks a hiatus in human occupation or major changes in site use. Our results are consistent with melting of sediments to temperatures >2,200 °C by the thermal radiation and air shocks produced by passage of an extraterrestrial object through the atmosphere; they are inconsistent with volcanic, cosmic, anthropogenic, lightning, or authigenic sources. We also produced spherules from wood in the laboratory at >1,730 °C, indicating that impact-related incineration of biomass may have contributed to spherule production. At 12.8 ka, an estimated 10 million tonnes of spherules were distributed across ∼50 million square kilometers, similar to well-known impact strewnfields and consistent with a major cosmic impact event.
Link
Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago
James H. Wittke et al.
Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently confirmed in eight studies, but unconfirmed in two others, resulting in continued dispute about their occurrence, distribution, and origin. To further address this dispute and better identify YDB spherules, we present results from one of the largest spherule investigations ever undertaken regarding spherule geochemistry, morphologies, origins, and processes of formation. We investigated 18 sites across North America, Europe, and the Middle East, performing nearly 700 analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analyses and scanning electron microscopy for surface microstructural characterization. Twelve locations rank among the world’s premier end-Pleistocene archaeological sites, where the YDB marks a hiatus in human occupation or major changes in site use. Our results are consistent with melting of sediments to temperatures >2,200 °C by the thermal radiation and air shocks produced by passage of an extraterrestrial object through the atmosphere; they are inconsistent with volcanic, cosmic, anthropogenic, lightning, or authigenic sources. We also produced spherules from wood in the laboratory at >1,730 °C, indicating that impact-related incineration of biomass may have contributed to spherule production. At 12.8 ka, an estimated 10 million tonnes of spherules were distributed across ∼50 million square kilometers, similar to well-known impact strewnfields and consistent with a major cosmic impact event.
Link
May 16, 2013
Toba eruption did not cause volcanic winter in Africa ~75ka
PNAS May 14, 2013 vol. 110 no. 20 8025-8029 doi: 10.1073/pnas.1301474110
Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka
Christine S. Lane et al.
The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea. A major climatic downturn observed within the Greenland ice cores has been attributed to the cooling effects of the ash and aerosols ejected during the eruption of the Youngest Toba Tuff (YTT). These events coincided roughly with a hypothesized human genetic bottleneck, when the number of our species in Africa may have been reduced to near extinction. Some have speculated that the demise of early modern humans at that time was due in part to a dramatic climate shift triggered by the supereruption. Others have argued that environmental conditions would not have been so severe to have such an impact on our ancestors, and furthermore, that modern humans may have already expanded beyond Africa by this time. We report an observation of the YTT in Africa, recovered as a cryptotephra layer in Lake Malawi sediments, >7,000 km west of the source volcano. The YTT isochron provides an accurate and precise age estimate for the Lake Malawi paleoclimate record, which revises the chronology of past climatic events in East Africa. The YTT in Lake Malawi is not accompanied by a major change in sediment composition or evidence for substantial temperature change, implying that the eruption did not significantly impact the climate of East Africa and was not the cause of a human genetic bottleneck at that time.
Link
Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka
Christine S. Lane et al.
The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea. A major climatic downturn observed within the Greenland ice cores has been attributed to the cooling effects of the ash and aerosols ejected during the eruption of the Youngest Toba Tuff (YTT). These events coincided roughly with a hypothesized human genetic bottleneck, when the number of our species in Africa may have been reduced to near extinction. Some have speculated that the demise of early modern humans at that time was due in part to a dramatic climate shift triggered by the supereruption. Others have argued that environmental conditions would not have been so severe to have such an impact on our ancestors, and furthermore, that modern humans may have already expanded beyond Africa by this time. We report an observation of the YTT in Africa, recovered as a cryptotephra layer in Lake Malawi sediments, >7,000 km west of the source volcano. The YTT isochron provides an accurate and precise age estimate for the Lake Malawi paleoclimate record, which revises the chronology of past climatic events in East Africa. The YTT in Lake Malawi is not accompanied by a major change in sediment composition or evidence for substantial temperature change, implying that the eruption did not significantly impact the climate of East Africa and was not the cause of a human genetic bottleneck at that time.
Link
February 20, 2013
AAPA 2013 abstracts
The program of the 2013 meeting of the American Association of Physical Anthropologists is now online (pdf). As always, there is plenty of interest here, so I'll just highlight a few titles that caught my eye; feel free to add more in the comments.
Neolithic human mitochondrial haplogroup H genomes and the genetic origins of Europeans.
Investigating lactase persistence in a Medieval German cemetery: A step towards understanding the rise of the European lactase persistence polymorphism (-3910C/T).
Peeling back the layers: additional evidence for the date of the Petralona skull (Homo heidelbergensis), Greece.
Neolithic human mitochondrial haplogroup H genomes and the genetic origins of Europeans.
Haplogroup (hg) H dominates present-day Western European mitochondrial (mt) DNA variability (>40%), yet was less prevalent amongst early Neolithic farmers (~19%) and virtually absent in Mesolithic hunter-gatherers. To investigate this haplogroup’s significance in the maternal population history of Europeans we employed novel techniques such as DNA immortalization and hybridization-enrichment to sequence 39 hg H mt genomes from ancient human remains across a transect through time in Neolithic Central Europe. The results of our population genetic analyses reveal that the current patterns of diversity and distribution of hg H were largely established during the Mid-Neolithic, but with substantial genetic contributions from subsequent pan-European cultures such as the Bell Beakers, which expanded out of Iberia in the Late Neolithic (~2800 BC). Using a strict diachronic approach allowed us to reconcile ‘real-time’ genetic data from the most common European mtDNA hg with cultural changes that took place between the Early Neolithic (~5450 BC) and Bronze Age (~2200 BC) in Central Europe. This revealed the Late Neolithic (2800-2200 BC) as a dynamic period that profoundly shaped the genetic landscape of modern-day Europeans. Furthermore, linking ancient hg H genome sequences to specific points in time by using radiocarbon dates as tip calibrations allowed us to reconstruct a precise lineage history of hg H and to calculate a mutation rate 45% higher than traditional estimates based on the human/chimp split.Preliminary research on hereditary features of Yinxu Population.
... The 37 individuals sampled in this study have been discovered in middle to small size burials, and therefore constitute a representative sample to study Yinxu commoners’ society. Mitochondrial DNA analysis showed that the Yinxu population included the haplogroups D, G, A, C, Z, M10, M*, B, F and N9a. According to the analysis of molecular variance, the distribution frequency and the rare published data, the Yinxu population shows a closest genetic affinity with the populations of Dadianzi and Zhukaigou early Bronze Age sites (Inner Mongolia), but a more distant relation to the historical period populations. The Yinxu population is also very similar to the modern northern Han Chinese. ...
Investigating lactase persistence in a Medieval German cemetery: A step towards understanding the rise of the European lactase persistence polymorphism (-3910C/T).
Previous ancient DNA-based studies on the Neolithic found that the incidence of LP falls below detection levels in most regions. Our research shows that between the Neolithic and Medieval periods, the frequency of LP rose from near 0% to over 50%. Also, given that the frequency of LP genotypes in modern-day Germany is estimated at 78.5%, our results indicate that rather than being stable by the Medieval period, the lactase persistent genotype has continued to increase in frequency over the last 1000 years. This new evidence sheds light on the dynamic evolutionary history of the European lactase persistent trait and its global cultural implications.New Neanderthal remains from Kalamakia cave, Mani peninsula, Southern Greece.
Peeling back the layers: additional evidence for the date of the Petralona skull (Homo heidelbergensis), Greece.
,.. We conclude that there is no white sinter deposited directly on the skull and therefore the initial date of the skull given by Henning et al. and Grun’s revised date of ca. 200 ka are correct.Analysis of archaic introgression in Ötzi the Tyrolean Iceman, a 5300 year-old prehistoric modern human.
... We carried out a series of comparisons to address these questions. By examining the Neandertal similarity of individuals from the 1000 Genomes Project, we have substantially expanded the sample of Neandertal-human comparisons. We also examined the genome of the Tyrolean Iceman, a European from approximately 5300 years ago. This is the first comparison of Neandertal genomes to the genome of a prehistoric modern human individual.A quantitative approach for late Pleistocene hominin brain size.
... The results of our study show that Neanderthals have smaller brains than the Pleistocene AMH despite the fact that the latter are smaller in body mass. However, the Holocene AMH (7 populations) have smaller brain sizes than those of Neanderthals. ...Re-evaluating the functional and adaptive significance of Neandertal nasofacial anatomy.
... Among Middle and Late Pleistocene Homo, there is evidence that nasal morphology varies with climate, albeit within an archaic architectural nasofacial framework. Neandertal internal nasal dimensions are greater in both height and length than archaic humans from sub-Saharan Africa. Furthermore, while other aspects of the nose are relatively broad, superior internal breadth dimensions in Neandertals are narrowed relative to sub-Saharan archaics. These differences parallel those seen in modern humans, indicating that Neandertals had an increased capacity for nasal heat and moisture exchange over their African counterparts and thus exhibit clear evidence for cold-climate adaptation.
January 25, 2013
The case for earlier Out-of-Africa (Boivin et al. 2013)
An informative review critical of the ~60kya coastal-Out-of-Africa hypothesis. On the left, the authors' estimate of the distribution of hominin groups during MIS5.
From the paper:
Human Dispersal Across Diverse Environments of Asia during the Upper Pleistocene
Nicole Boivin et al.
The initial out of Africa dispersal of H. sapiens, which saw anatomically modern humans reach the Levant in Marine Isotope Stage 5, is generally regarded as a ‘failed dispersal’. Fossil, archaeological and genetic findings are seen to converge around a consensus view that a single population of H. sapiens exited Africa sometime around 60 thousand years ago (ka), and rapidly reached Australia by following a coastal dispersal corridor. We challenge the notion that current evidence supports this straightforward model. We argue that the fossil and archaeological records are too incomplete, the coastal route too problematic, and recent genomic evidence too incompatible for researchers not to remain fully open to other hypotheses. We specifically explore the possibility of a sustained exit by anatomically modern humans, drawing in particular upon palaeoenvironmental data across southern Asia to demonstrate its feasibility. Current archaeological, genetic and fossil data are not incompatible with the model presented, and appear to increasingly favour a more complex out of Africa scenario involving multiple exits, varying terrestrial routes, a sub-divided African source population, slower progress to Australia, and a degree of interbreeding with archaic varieties of Homo.
Link
From the paper:
Another under-appreciated issue is the anomalous nature of the genetic evidence for a rapid spread of modern humans from Africa to Asia. Echoing the fossil date anomaly, the mtDNA branch lengths for sampled populations are longest for those which are farthest east, in Near Oceania, and shortest in the Asian areas that would have been encountered first (Merriwether et al., 2005; Oppenheimer, 2009). The real problem, however, is that the variation in branch lengths suggests that a single genotype engaged in the expansion actually existed for 30 ka, which does not support a rapid expansion. The anomaly can be explained by what we call an an ‘M buffer’ effect (see Supplementary material A) which implies that the branch ages we observe are considerable underestimates of the time of arrival of the genotype to these areas. Such anomalously long-lived genotypes have been directly observed through ancient DNA in species such as the Iberian lynx (Dalen et al., 2011).and:
We have focused here on the possibility that the modern human exit recorded by fossil evidence in the Levant in MIS 5 does not represent a failed dispersal, and that in fact our species was not only in the Levant but also the Arabian peninsula during this marine isotope stage, and spread to India before the Toba eruption at 74 ka (Petraglia et al., 2007). Another valid hypothesis we do not explore here is that H. sapiens was able to leave Africa in MIS 6 via a grassland corridor (Frumkin et al., 2011; see also Scally and Durbin, 2012). Yet another is that our species dispersed out of Africa shortly after its first appearance c. 195 ka, in MIS 7 (Dennell and Roebroeks, 2005: 1102). One other possibility is that there were several, separate dispersals of our species out of Africa (Dennell and Petraglia, 2012). At the same time, we acknowledge that major demographic changes occurred in MIS 4 and MIS 3, perhaps explaining the relatively young mtDNA coalescence age in living populations. The increasing evidence for complexity as well as the clear patterns of bias for all records, whether archaeological, fossil or genetic, suggests the need for an open mind to multiple scenarios for Out of Africa, as well as for more rather than less complex models of H. sapiens dispersal across Eurasia.Quaternary International doi:10.1016/j.quaint.2013.01.008
Human Dispersal Across Diverse Environments of Asia during the Upper Pleistocene
Nicole Boivin et al.
The initial out of Africa dispersal of H. sapiens, which saw anatomically modern humans reach the Levant in Marine Isotope Stage 5, is generally regarded as a ‘failed dispersal’. Fossil, archaeological and genetic findings are seen to converge around a consensus view that a single population of H. sapiens exited Africa sometime around 60 thousand years ago (ka), and rapidly reached Australia by following a coastal dispersal corridor. We challenge the notion that current evidence supports this straightforward model. We argue that the fossil and archaeological records are too incomplete, the coastal route too problematic, and recent genomic evidence too incompatible for researchers not to remain fully open to other hypotheses. We specifically explore the possibility of a sustained exit by anatomically modern humans, drawing in particular upon palaeoenvironmental data across southern Asia to demonstrate its feasibility. Current archaeological, genetic and fossil data are not incompatible with the model presented, and appear to increasingly favour a more complex out of Africa scenario involving multiple exits, varying terrestrial routes, a sub-divided African source population, slower progress to Australia, and a degree of interbreeding with archaic varieties of Homo.
Link
January 15, 2013
Climate and history (in Eastern Europe)
PNAS doi: 10.1073/pnas.1211485110
Filling the Eastern European gap in millennium-long temperature reconstructions
Ulf Büntgen et al.
Tree ring–based temperature reconstructions form the scientific backbone of the current global change debate. Although some European records extend into medieval times, high-resolution, long-term, regional-scale paleoclimatic evidence is missing for the eastern part of the continent. Here we compile 545 samples of living trees and historical timbers from the greater Tatra region to reconstruct interannual to centennial-long variations in Eastern European May–June temperature back to 1040 AD. Recent anthropogenic warming exceeds the range of past natural climate variability. Increased plague outbreaks and political conflicts, as well as decreased settlement activities, coincided with temperature depressions. The Black Death in the mid-14th century, the Thirty Years War in the early 17th century, and the French Invasion of Russia in the early 19th century all occurred during the coldest episodes of the last millennium. A comparison with summer temperature reconstructions from Scandinavia, the Alps, and the Pyrenees emphasizes the seasonal and spatial specificity of our results, questioning those large-scale reconstructions that simply average individual sites.
Link
Filling the Eastern European gap in millennium-long temperature reconstructions
Ulf Büntgen et al.
Tree ring–based temperature reconstructions form the scientific backbone of the current global change debate. Although some European records extend into medieval times, high-resolution, long-term, regional-scale paleoclimatic evidence is missing for the eastern part of the continent. Here we compile 545 samples of living trees and historical timbers from the greater Tatra region to reconstruct interannual to centennial-long variations in Eastern European May–June temperature back to 1040 AD. Recent anthropogenic warming exceeds the range of past natural climate variability. Increased plague outbreaks and political conflicts, as well as decreased settlement activities, coincided with temperature depressions. The Black Death in the mid-14th century, the Thirty Years War in the early 17th century, and the French Invasion of Russia in the early 19th century all occurred during the coldest episodes of the last millennium. A comparison with summer temperature reconstructions from Scandinavia, the Alps, and the Pyrenees emphasizes the seasonal and spatial specificity of our results, questioning those large-scale reconstructions that simply average individual sites.
Link
January 03, 2013
Body form variation of prehistoric Jomon (Fukase et al. 2012)
Am J Phys Anthropol DOI: 10.1002/ajpa.22112
Geographic variation in body form of prehistoric Jomon males in the Japanese archipelago: Its ecogeographic implications
Hitoshi Fukase et al.
Diversity of human body size and shape is often biogeographically interpreted in association with climatic conditions. According to Bergmann's and Allen's rules, populations in regions with a cold climate are expected to display an overall larger body and smaller/shorter extremities than those in warm/hot environments. In the present study, the skeletal limb size and proportions of prehistoric Jomon hunter-gatherers, who extensively inhabited subarctic to subtropical areas in the ancient Japanese archipelago, were examined to evaluate whether or not the inter-regional differences follow such ecogeographic patterns. Results showed that the Jomon intralimb proportions including relative distal limb lengths did not differ significantly among five regions from northern Hokkaido to the southern Okinawa Islands. This suggests a limited co-variability of the intralimb proportions with climate, particularly within genealogically close populations. In contrast, femoral head breadth (associated with body mass) and skeletal limb lengths were found to be significantly and positively correlated with latitude, suggesting a north-south geographical cline in the body size. This gradient therefore comprehensively conforms to Bergmann's rule, and may stem from multiple potential factors such as phylogenetic constraints, microevolutionary adaptation to climatic/geographic conditions during the Jomon period, and nutritional and physiological response during ontogeny. Specifically, the remarkably small-bodied Jomon in the Okinawa Islands can also be explained as an adjustment to subtropical and insular environments. Thus, the findings obtained in this study indicate that Jomon people, while maintaining fundamental intralimb proportions, displayed body size variation in concert with ambient surroundings.
Link
Geographic variation in body form of prehistoric Jomon males in the Japanese archipelago: Its ecogeographic implications
Hitoshi Fukase et al.
Diversity of human body size and shape is often biogeographically interpreted in association with climatic conditions. According to Bergmann's and Allen's rules, populations in regions with a cold climate are expected to display an overall larger body and smaller/shorter extremities than those in warm/hot environments. In the present study, the skeletal limb size and proportions of prehistoric Jomon hunter-gatherers, who extensively inhabited subarctic to subtropical areas in the ancient Japanese archipelago, were examined to evaluate whether or not the inter-regional differences follow such ecogeographic patterns. Results showed that the Jomon intralimb proportions including relative distal limb lengths did not differ significantly among five regions from northern Hokkaido to the southern Okinawa Islands. This suggests a limited co-variability of the intralimb proportions with climate, particularly within genealogically close populations. In contrast, femoral head breadth (associated with body mass) and skeletal limb lengths were found to be significantly and positively correlated with latitude, suggesting a north-south geographical cline in the body size. This gradient therefore comprehensively conforms to Bergmann's rule, and may stem from multiple potential factors such as phylogenetic constraints, microevolutionary adaptation to climatic/geographic conditions during the Jomon period, and nutritional and physiological response during ontogeny. Specifically, the remarkably small-bodied Jomon in the Okinawa Islands can also be explained as an adjustment to subtropical and insular environments. Thus, the findings obtained in this study indicate that Jomon people, while maintaining fundamental intralimb proportions, displayed body size variation in concert with ambient surroundings.
Link
October 25, 2012
Wide-bodied early Holocene north Americans
Am J Phys Anthropol DOI: 10.1002/ajpa.22154
Skeletal variation among early holocene north american humans: Implications for origins and diversity in the americas
Benjamin M. Auerbach
The movement of humans into the Americas remains a major topic of debate among scientific disciplines. Central to this discussion is ascertaining the timing and migratory routes of the earliest colonizers, in addition to understanding their ancestry. Molecular studies have recently argued that the colonizing population was isolated from other Asian populations for an extended period before proceeding to colonize the Americas. This research has suggested that Beringia was the location of this “incubation,” though archaeological and skeletal data have not yet supported this hypothesis. This study employs the remains of the five most complete North American male early Holocene skeletons to examine patterns of human morphology at the earliest observable time period. Stature, body mass, body breadth, and limb proportions are examined in the context of male skeletal samples representing the range of morphological variation in North America in the last two millennia of the Holocene. These are also compared with a global sample. Results indicate that early Holocene males have variable postcranial morphologies, but all share the common trait of wide bodies. This trait, which is retained in more recent indigenous North American groups, is associated with adaptations to cold climates. Peoples from the Americas exhibit wider bodies than other populations sampled globally. This pattern suggests the common ancestral population of all of these indigenous American groups had reduced morphological variation in this trait. Furthermore, this provides support for a single, possibly high latitude location for the genetic isolation of ancestors of the human colonizers of the Americas.
Link
Skeletal variation among early holocene north american humans: Implications for origins and diversity in the americas
Benjamin M. Auerbach
The movement of humans into the Americas remains a major topic of debate among scientific disciplines. Central to this discussion is ascertaining the timing and migratory routes of the earliest colonizers, in addition to understanding their ancestry. Molecular studies have recently argued that the colonizing population was isolated from other Asian populations for an extended period before proceeding to colonize the Americas. This research has suggested that Beringia was the location of this “incubation,” though archaeological and skeletal data have not yet supported this hypothesis. This study employs the remains of the five most complete North American male early Holocene skeletons to examine patterns of human morphology at the earliest observable time period. Stature, body mass, body breadth, and limb proportions are examined in the context of male skeletal samples representing the range of morphological variation in North America in the last two millennia of the Holocene. These are also compared with a global sample. Results indicate that early Holocene males have variable postcranial morphologies, but all share the common trait of wide bodies. This trait, which is retained in more recent indigenous North American groups, is associated with adaptations to cold climates. Peoples from the Americas exhibit wider bodies than other populations sampled globally. This pattern suggests the common ancestral population of all of these indigenous American groups had reduced morphological variation in this trait. Furthermore, this provides support for a single, possibly high latitude location for the genetic isolation of ancestors of the human colonizers of the Americas.
Link
October 21, 2012
Post-LGM expansion of mtDNA?
This issue keeps appearing and re-appearing. It is perhaps due to a tendency of conflating spatial population expansions with the proliferation of descendants within a lineage. The two are not necessarily related. Genetic-only methods can pick up on the signal of common descent and population growth, but cannot do the same for the signal of spatial expansion. Whether this growth happens (i) in situ for a long time, and only lately becomes a spatial expansion, or (ii) at the same time as the spatial expansion, or indeed (iii) long after it, will result in coalescences that precede, coincide with, or follow the actual spatial expansion event.
It is difficult to see how Europe was being filled up for thousands of years by a population taking advantage of post-glacial warming conditions, and, yet, when we actually look at ancient DNA from Europeans who lived just before the advent of farming, they show little evidence of possessing (m)any of the lineages that had been supposedly expanding in Europe since the LGM.
SCIENTIFIC REPORTS doi:10.1038/srep00745
MtDNA analysis of global populations support that major population expansions began before Neolithic Time
Hong-Xiang Zheng et al.
Agriculture resulted in extensive population growths and human activities. However, whether major human expansions started after Neolithic Time still remained controversial. With the benefit of 1000 Genome Project, we were able to analyze a total of 910 samples from 11 populations in Africa, Europe and Americas. From these random samples, we identified the expansion lineages and reconstructed the historical demographic variations. In all the three continents, we found that most major lineage expansions (11 out of 15 star lineages in Africa, all autochthonous lineages in Europe and America) coalesced before the first appearance of agriculture. Furthermore, major population expansions were estimated after Last Glacial Maximum but before Neolithic Time, also corresponding to the result of major lineage expansions. Considering results in current and previous study, global mtDNA evidence showed that rising temperature after Last Glacial Maximum offered amiable environments and might be the most important factor for prehistorical human expansions.
Link
It is difficult to see how Europe was being filled up for thousands of years by a population taking advantage of post-glacial warming conditions, and, yet, when we actually look at ancient DNA from Europeans who lived just before the advent of farming, they show little evidence of possessing (m)any of the lineages that had been supposedly expanding in Europe since the LGM.
SCIENTIFIC REPORTS doi:10.1038/srep00745
MtDNA analysis of global populations support that major population expansions began before Neolithic Time
Hong-Xiang Zheng et al.
Agriculture resulted in extensive population growths and human activities. However, whether major human expansions started after Neolithic Time still remained controversial. With the benefit of 1000 Genome Project, we were able to analyze a total of 910 samples from 11 populations in Africa, Europe and Americas. From these random samples, we identified the expansion lineages and reconstructed the historical demographic variations. In all the three continents, we found that most major lineage expansions (11 out of 15 star lineages in Africa, all autochthonous lineages in Europe and America) coalesced before the first appearance of agriculture. Furthermore, major population expansions were estimated after Last Glacial Maximum but before Neolithic Time, also corresponding to the result of major lineage expansions. Considering results in current and previous study, global mtDNA evidence showed that rising temperature after Last Glacial Maximum offered amiable environments and might be the most important factor for prehistorical human expansions.
Link
October 16, 2012
Compasses would have pointed south for 440 years ~41 thousand years ago.
Recent research indicates that when the Campanian Ignimbrite event occurred, the Neandertals were already on the way out. I'd say that the circa 40ka period would make the ideal setting for some good palaeo-fiction. You have volcanic explosions, modern humans replacing Neandertals, magnetic field reversals, and a new set of characters in the mysterious Denisovans. This stuff practically writes itself. On that topic, does anyone have any good prehistoric fiction recommendations?
Earth and Planetary Science Letters Volumes 351–352, 15 October 2012, Pages 54–69
Dynamics of the Laschamp geomagnetic excursion from Black Sea sediments
N.R. Nowaczyk et al.
Investigated sediment cores from the southeastern Black Sea provide a high-resolution record from mid latitudes of the Laschamp geomagnetic polarity excursion. Age constraints are provided by 16 AMS 14C ages, identification of the Campanian Ignimbrite tephra (39.28±0.11 ka), and by detailed tuning of sedimentologic parameters of the Black Sea sediments to the oxygen isotope record from the Greenland NGRIP ice core. According to the derived age model, virtual geomagnetic pole (VGP) positions during the Laschamp excursion persisted in Antarctica for an estimated 440 yr, making the Laschamp excursion a short-lived event with fully reversed polarity directions. The reversed phase, centred at 41.0 ka, is associated with a significant field intensity recovery to 20% of the preceding strong field maximum at ∼50 ka. Recorded field reversals of the Laschamp excursion, lasting only an estimated ∼250 yr, are characterized by low relative paleointensities (5% relative to 50 ka). The central, fully reversed phase of the Laschamp excursion is bracketed by VGP excursions to the Sargasso Sea (∼41.9 ka) and to the Labrador Sea (∼39.6 ka). Paleomagnetic results from the Black Sea are in excellent agreement with VGP data from the French type locality which facilitates the chronological ordering of the non-superposed lavas that crop out at Laschamp–Olby. In addition, VGPs between 34 and 35 ka reach low northerly to equatorial latitudes during a clockwise loop, inferred to be the Mono lake excursion.
Link
Earth and Planetary Science Letters Volumes 351–352, 15 October 2012, Pages 54–69
Dynamics of the Laschamp geomagnetic excursion from Black Sea sediments
N.R. Nowaczyk et al.
Investigated sediment cores from the southeastern Black Sea provide a high-resolution record from mid latitudes of the Laschamp geomagnetic polarity excursion. Age constraints are provided by 16 AMS 14C ages, identification of the Campanian Ignimbrite tephra (39.28±0.11 ka), and by detailed tuning of sedimentologic parameters of the Black Sea sediments to the oxygen isotope record from the Greenland NGRIP ice core. According to the derived age model, virtual geomagnetic pole (VGP) positions during the Laschamp excursion persisted in Antarctica for an estimated 440 yr, making the Laschamp excursion a short-lived event with fully reversed polarity directions. The reversed phase, centred at 41.0 ka, is associated with a significant field intensity recovery to 20% of the preceding strong field maximum at ∼50 ka. Recorded field reversals of the Laschamp excursion, lasting only an estimated ∼250 yr, are characterized by low relative paleointensities (5% relative to 50 ka). The central, fully reversed phase of the Laschamp excursion is bracketed by VGP excursions to the Sargasso Sea (∼41.9 ka) and to the Labrador Sea (∼39.6 ka). Paleomagnetic results from the Black Sea are in excellent agreement with VGP data from the French type locality which facilitates the chronological ordering of the non-superposed lavas that crop out at Laschamp–Olby. In addition, VGPs between 34 and 35 ka reach low northerly to equatorial latitudes during a clockwise loop, inferred to be the Mono lake excursion.
Link
September 28, 2012
La Bastida, Bronze Age Iberian fortified site
From a website dedicated to it:
Related: 4.2 kiloyear event, and El Argar.
La Bastida (Totana, Murcia) is one of the most important archaeological sites of Prehistory in Europe. It was inhabited about 4000 years ago in the Bronze Age, and it has a great potential to understand our past and the heritage and cultural projection of Murcia Region.
The archaeological site is located in the Sierra Tercia, on a steep hill at confluence of the Rambla de Lebor and Salado Cliff around 6 km west of Totana town. The four hectares of surface make it one of the most extensive sites and it can only be compared to the one that occupied the present town of Lorca.From a recent press release:
The Argaric society was a milestone of sedentary life, urbanism, metallurgy and political and economic inequalities. La Bastida offers a unique and exceptional opportunity to understand this key stage of our past.
La Bastida unearths 4,200-year-old fortification, unique in continental Europe
Similar characteristics have not been observed in other constructions of the Bronze Age, with three-metre thick walls, square towers originally measuring up to seven metres, a monumental entrance and an ogival arched postern gate; a fully conserved architectural element unique in Europe in that period.
The wall protected a city measuring 4 hectares located on top of a hill. With architectural elements reminiscent of people with Eastern styled military skills, its model is typical of ancient civilisations of the Mediterranean, such as the second city of Troy.
...
One of the most relevant architectural elements discovered is the ogival arched postern gate, or secondary door, located near the main entrance. The arch is in very good conditions and is the first one to be found in Prehistoric Europe. Precedents can be found in the second city of Troy (Turkey) and in the urban world of the Middle East (Palestine, Israel and Jordan), influenced by the civilisations of Mesopotamia and Egypt. This indicates that people from the East participated in the construction of the fortification. These people would have reached La Bastida after the crisis which devastated their region 4,300 years ago. It was not until some 400 to 800 years later that civilisations like the Hittites and Mycenaeans, or city-states such as Ugarit, incorporated these innovative methods into their military architecture.
Related: 4.2 kiloyear event, and El Argar.
Subscribe to:
Posts (Atom)