вторник, 31 марта 2020 г.

Museum of the Bible's Dead Sea Scroll collection found to be fakes

A collection of supposedly valuable Dead Sea Scroll fragments on display at the Museum of the Bible in Washington DC has been found to be fake.

Museum of the Bible's Dead Sea Scroll collection found to be fakes
A Dead Sea Scrolls fragment from the book of Genesis, part of Museum of the Bible's Scholars Initiative research project
published by Brill in 2016. Of the museum's 13 published scrolls, at least six are of dubious authenticity
[Credit: Bruce & Kenneth Zuckerman & Marilyn J. Lundberg, West Semitic Research,
courtesy of Museum of the Bible]
After six months of analysis, experts released a 200-page report detailing how the fragments were forged - likely made from old shoe leather.

"Each exhibits characteristics that suggest they are deliberate forgeries," the analysts said in a statement.

The scrolls are a set of ancient manuscripts of the Hebrew Bible.

The first of the scrolls were found in caves in Qumran on the western shore of the Dead Sea in 1947. They were reportedly first discovered by a young Bedouin shepherd searching for lost sheep. Their discovery is considered to be among the most significant archaeological finds in history.

The majority are held in a collection by the Israeli government. The fakes were among the most valuable artefacts in the Museum of the Bible's collection.

Costing $500m (£386m), the museum was opened by Evangelical Christian and billionaire Steve Green in 2017.

Mr Green has not disclosed how much was paid for the 16 fragments but similar, authentic artefacts may be sold for millions.

"After an exhaustive review of all the imaging and scientific analysis results, it is evident that none of the textual fragments in Museum of the Bible's Dead Sea Scroll collection are authentic," said the head of the investigation, Colette Loll of Art Fraud Insights, in a statement.

Since 2002, previously unknown textual fragments - believed to be biblical artefacts belonging to the Dead Sea Scroll - surfaced on the antiquities market.

The Museum of the Bible purchased 16 of these fragments from four individual private collectors. Thirteen of these were published by a team of scholars in 2016 "to provide a comprehensive physical and textual description of the fragments," the analysts wrote. "At the time of publication, no scientific examination of the Museum's scroll fragments had been carried out."

"Since publication, scholars have expressed growing concern about the authenticity of these fragments."

To make convincing fakes, researchers estimate the forgers coated the scraps with a "shiny amber material... most likely animal skin glue".

The exhaustive report was the product of a six-month effort, including 3D microscopes, infrared spectroscopy and "energy dispersive X-ray analysis".

Part of the same collection had already been removed from display after tests in October 2018 found them to be inauthentic too.

These earlier tests were ordered after biblical scholars who examined 13 of the museum's previously unstudied fragments said there was a "high probability" that a number of them were modern forgeries.

And this was not the first time the museum's owners have faced controversy. In 2017, Mr Green's company the Hobby Lobby paid a $3m fine (£2.3m) and returned thousands of items after the US Department of Justice accused it of smuggling artifacts from Iraq.

Source: BBC News Website [March 16, 2020]

* This article was originally published here

Study reveals diet of ‘Theropithecus oswaldi’ found in Spain's Cueva Victoria

A study published in Journal of Human Evolution  reveals for the first time the diet of the fossil baboon Theropithecus oswaldi found in Cueva Victoria in Cartagena (Murcia, Spain), the only site in Europe with remains of this primate whose origins date back to four million years ago in eastern Africa.

Study reveals diet of ‘Theropithecus oswaldi’ found in Spain's Cueva Victoria
Theropithecus oswaldi cast [Credit: Smithsonian]
The new study analyses the diet of the only fossil remains of this primate with the analysis of buccal dental microwear. According to the conclusions, the eating pattern of this guenon—the most abundant in the fossil records from the African Pleistocene—would be different than the one in the baboon Theropithecus gelada—the phylogenetically closest species living in Semien Mountains, northern Ethiopia, at the current moment—which usually eats herbs and stalks.

The study, led by the lecturers Laura Martinez and Alejandro Perez-Perez, from the Faculty of Biology of the University of Barcelona (UB), counts on the participation of experts from the Faculty of Earth Sciences and the Faculty of Psychology of the UB as well as members from the Autonomous University of Barcelona, University of Alicante, the Museum of Orce Prehistory and Palaeontology (Granada) and the George Washington University (United States).

Cueva Victoria: The long journey of the African baboon Theropithecus oswaldi

The genre Theropithecus spread over the Sahara Desert, from east to north and south in the African continent. Its evolutionary lineage, also present in some European and Asian areas, reached its limit of disappearance about 500,000 years ago. Today, it would be only represented by the species Theropithecus gelada, a baboon which only eats plants and shows an ecological profile more similar to herbivore animals rather than primates.

Study reveals diet of ‘Theropithecus oswaldi’ found in Spain's Cueva Victoria
The presence of this African guenon in the south-eastern area of the Iberian Peninsula strengthens the hypothesis
of the animal dispersal models going from the African continent to Europe during the Pleistocene
through the Strait of Gibraltar [Credit: University Of Barcelona]
In 1990, the excavation campaign led by the palaeontologist Josep Gibert found the first fossil remain—a tooth—of Theropithecus oswaldi (Journal of Human Evolution, 1995). This cave, an old manganese mine, provided with fossil remains of about a hundred species of vertebrates and it is one of the few European sites of the early Pleistocene with remains of human species. Outside the African continent, the fossil records of this baboon are scarce and researchers have only found other remains in Ubeidiya (Israel) and Minzapur (India).

The new fossil evidence of T. oswaldi, which date back to 900,000 and 850,000 million years ago, were recovered by a team led by the lecturers Carles Ferrandez-Canadell and Lluis Gibert, from the Department of Mineralogy, Petrology and Applied Geology of the Faculty of Earth Sciences of the UB. The presence of this African guenon in the south-eastern area of the Iberian Peninsula strengthens the hypothesis of the animal dispersal models going from the African continent to Europe during the Pleistocene through the Strait of Gibraltar.

What was the fossil baboon diet like in the south of the Iberian Peninsula?

The analysis of the produced buccal-dental stretch marks due to food intake reveal the T. oswaldi specimens in Cueva Victoria "would have a more abrasive diet compared to the current T. gelada, and more similar to the diet of other primates such as mangabeys i(Cercocebus sp) and mandrylles (Mandrillys sphinx), which eat fruits and seeds in forested and semiopen ecosystems," notes Laura Martinez, lecturer at the Department of Evolutionary Biology, Ecology and Environmental Sciences of the Faculty of Biology and first author of the study.

Study reveals diet of ‘Theropithecus oswaldi’ found in Spain's Cueva Victoria
Cueva Victoria provided with fossil remains of about a hundred species of vertebrates and it is one
of the few European sites of the early Pleistocene with remains of human species
[Credit: University Of Barcelona]
Other recent studies based on the observation of T. gelada in the area of Guassa, Ethiopia, describe a more diverse diet, with rhizome and tubers over the most unfavourable season. "The difference between T. oswaldi and T. gelada -continues the researcher- shows that the observed specialization in the current baboon could be a derived specialization which did not exist in the fossils of its lineage. This could respond to a regression in its ecological niche as an adaptation to anthropically altered ecosystems or as a result from climate change."

Source: University of Barcelona [March 24, 2020]

* This article was originally published here

понедельник, 30 марта 2020 г.

Study challenges common view of oxygen scarcity on Earth 2 billion years ago

Shungite, a unique carbon-rich sedimentary rock from Russia that deposited 2 billion years ago, holds clues about oxygen concentrations on Earth's surface at that time. Led by Professor Kurt Konhauser at the University of Alberta and Professor Kalle Kirsimäe at the University of Tartu, an international research team involving other colleagues from France, Norway, Russia, and USA, have found strikingly high molybdenum, uranium, and rhenium concentrations, as well as elevated uranium isotope ratios in drill cores that dissect the shungite rocks. These trace metals are only thought to be common in Earth's oceans and sediments when there is abundant oxygen around. The researchers found that such trace metal concentrations are unrivaled in early Earth's history, suggesting elevated levels of oxygen at the time when the shungite was deposited.

Study challenges common view of oxygen scarcity on Earth 2 billion years ago
Two-billion-year-old shungite, a type of sedimentary rock exposed in north-western Russia, records evidence
for balmy, oxygen-rich conditions on the early Earth [Credit: K. Paiste]
"What is puzzling is that the widely-accepted models of Earth's carbon and oxygen cycles predict that shungite should have been deposited at a time of rapid decrease in oxygen levels," says Mänd, a PhD candidate at the University of Alberta and lead author of the study.

Most scientists agree that atmospheric oxygen levels significantly increased about 2.4 billion years ago--known as the Great Oxidation Event (GOE)--and reached about half of modern levels by about 2.1 billion years. The GOE was also accompanied by a shift in carbon isotope ratios in sedimentary rocks. To scientists, this fits the story--the anomalous carbon isotope ratios reflect the burial of massive amounts of plankton as organic matter in ocean sediments, which in turn lead to the generation of excess oxygen. But the prevailing understanding is that immediately after this period of high concentrations, oxygen levels decreased again and remained low for almost a billion years during Earth's so-called 'middle age'.

"Fresh drill cores that we obtained from the Lake Onega area with the support of University of Tartu and Tallinn University of Technology provide some of the best rock archives to decipher the environmental conditions immediately after the GOE" says Kirsimäe, coordinator of geological field work.

"What we found contradicts the prevailing view--essentially we have clear evidence that atmospheric oxygen levels rose even further after the carbon isotope anomaly ended," says Mänd. "This will force the Earth science community to rethink what drove the carbon and oxygen cycles on the early Earth."

These new findings are also crucial for understanding the evolution of complex life. Earth's 'middle age' represents the backdrop for the appearance of eukaryotes. Eukaryotes, the precursors to all complex life, including animals such as ourselves, generally require high oxygen levels in their environment to thrive. This work now strengthens the suggestion that suitable conditions for the evolution of complex life on early Earth existed for a much longer time than previously thought. As such, the findings indirectly support earlier studies where Prof. Konhauser was involved that revealed large, potentially eukaryotic trace fossils as old as 2.1 billion years.

Despite these new advances, the delay between the initial rise of oxygen and the appearance and radiation of eukaryotes, remains an area of active research; one that University of Tartu and University of Alberta researchers are well positioned to help answer.

The study is published in Nature Geoscience.

Source: Estonian Research Council [March 24, 2020]

* This article was originally published here

суббота, 28 марта 2020 г.

Fossil finds give clues about flying reptiles in the Sahara 100 million years ago

Three new species of toothed pterosaurs -- flying reptiles of the Cretaceous period, some 100 million years ago -- have been identified in Africa by an international team of scientists led by Baylor University.

Fossil finds give clues about flying reptiles in the Sahara 100 million years ago
Anhanguera soaring the skies over the Kem Kem with Coloborhynchus
and Ornithocheirus [Credit: Megan Jacobs]
The pterosaurs, which soared above a world dominated by predators, formed part of an ancient river ecosystem in Africa that teemed with life including fish, crocodiles, turtles and several predatory dinosaurs.

"Pterosaur remains are very rare, with most known from Europe, South America and Asia. These new finds are very exciting and provide a window into the world of pterosaurs in Cretaceous Africa," said lead author Megan L. Jacobs, a doctoral candidate in geosciences at Baylor University.

The study, published in the journal Cretaceous Research, is helping to uncover the poorly known evolutionary history of Africa during the time of the dinosaurs. The research finds that African pterosaurs were quite similar to those found on other continents. Their world included crocodile-like hunters and carnivorous dinosaurs, with few herbivores. Many predators, including the toothed pterosaurs, preyed on a superabundance of fish.

"For such large animals, they would have weighed very little," Jacobs said. "Their wingspans were around 10 to 13 feet, with their bones almost paper-thin and full of air, very similar to birds. This allowed these awesome creatures to reach incredible sizes and still be able to take off and soar the skies."

Pterosaurs snatched up their prey while on the wing, using a set of large spike-like teeth to grab. Large pterosaurs such as these would have been able to forage over hundreds of miles, with fossil evidence showing they flew between South America and Africa, similar to present-day birds such as condors and albatrosses, researchers said.

The specimens -- identified by researchers from chunks of jaws with teeth -- were obtained from fossil miners in a small village called Beggaa, just outside Erfoud in southeast Morocco. These villagers daily climb halfway up the side of a large escarpment, known as the Kem Kem beds, to a layer of a coarse sand, the most fossiliferous bed.

"They excavate everything they find, from teeth to bones to almost complete skeletons," Jacobs said. "They then sell their finds to dealers and scientists who conduct fieldwork, ensuring the villagers make enough money to survive while we get new fossils to describe. These pterosaur fragments are unique and can be identified easily -- if you know what to look for."

One of the species, Anhanguera, previously was only known to be from Brazil. Another, Ornithocheirus, had until now only been found in England and Middle Asia.

This year's find brings to five the total of toothed pterosaurs whose remains have been found in the Kem Kem beds, with the first described in the 1990s and the second one last year, Jacobs said. The specimens will be part of an acquisition in a museum in Morocco.

Source: Baylor University [March 25, 2020]

* This article was originally published here

пятница, 27 марта 2020 г.

Small horses got smaller, big tapirs got bigger 47 million years ago

The former coalfield of Geiseltal in Saxony-Anhalt has yielded large numbers of exceptionally preserved fossil animals, giving palaeontologists a unique window into the evolution of mammals 47 million years ago. A team led by the University of Tübingen and the Martin Luther University Halle-Wittenberg (MLU) has shown that the body size of two species of mammals developed in opposite directions. The study was published in Scientific Reports.

Small horses got smaller, big tapirs got bigger 47 million years ago
Window into the 47 million year old ecosystem of the Geiseltal fossil locality with the small-sized horse-ancestor
Propalaeotherium on the left, the ancient tapir Lophiodon in the middle, and a young terrestrial crocodile
Bergisuchus in the background [Credit: Márton Szabó]
47 million years ago - the middle Eocene - the Earth was much warmer and the area of Geiseltal was a swampy subtropical forest whose inhabitants included ancestors of the horse, ancient tapirs, large terrestrial crocodiles, as well as giant tortoises, lizards and ground-dwelling birds. So rich are the Geiseltal finds that they give researchers an unprecedented high-resolution picture of evolutionary dynamics at the population level.

A team led by Dr Márton Rabi from the University of Tübingen and the Martin Luther University Halle-Wittenberg (MLU) has shown that the body size of two species of mammals developed in opposite directions. The study, published in Scientific Reports, was carried out with Simon Ring and Professor Hervé Bocherens at the Senckenberg Centre for Human Evolution and Palaeoenvironment and the University of Tübingen in cooperation with Dr Oliver Wings from the MLU.

"We were initially interested in the evolution of the ancient horses, which were about the size of a Labrador dog. These animals are particularly abundant in the Geiseltal fossil record," Rabi says. Researchers initially believed they had several species of early horse. "However, we found that here, there was only one species, whose body size shrank significantly with time," Rabi explains. The team wanted to test whether this body size shift was climate-induced, since past global warming caused body-size reduction in ancient mammals.

Small horses got smaller, big tapirs got bigger 47 million years ago
Exceptionally-well fossilized skeletons of the ancient tapir Lophiodon (top) and the
ancestral horse Propalaeotherium (bottom) from the middle Eocene Geiseltal
 locality (Germany, Saxony-Anhalt) [Credit: Oliver Wings/MLU]
Carbon and oxygen isotope studies on fossil teeth provided the scientists with information about the local middle Eocene climate. "They indicate a humid tropical climate. However, we didn't find any evidence for climatic changes in Geiseltal over the period investigated," says Bocherens. To further test the data, the team sought to discover whether the dwarfing process was unique to the horses. For comparison, they examined the evolution of the tapir ancestor called Lophiodon.

"We had reason to question the Geiseltal's constant-climate data; so we expected that other mammals would show the same body-size trends as the horses," Simon Ring explains. In a surprising result, the tapirs - also a single species - revealed the opposite trend. They grew larger instead of shrinking. While the ancestors of the horse shrank from an average body weight of 39 kilograms to around 26 kilograms over about a million years, the tapirs increased from 124 kilograms to an average body weight of 223 kilograms.

Differing survival strategies

"All the data indicate that the body size of the horses and tapirs developed differently not because of the climate, but because of different life cycles," explains Bocherens. Small animals reproduce faster and die younger: Relative to their size, they don't have to eat as much to maintain their body mass and can devote more resources to having young. Larger animals live longer and have lower reproduction rates. They have to eat more and therefore have fewer resources for reproduction - but, being large, face fewer predators and can range further to get better food. That extends their lives and gives them more time to breed. The Geiseltal tapirs and the horses therefore likely maximized the different advantages of their respective life cycle strategies, which caused divergent body size evolution.

Exceptional fossil deposits

The Geiseltal fossil site is located in the eastern state of Saxony-Anhalt. In the course of open-cast brown coal mining between 1933 and 1993, tens of thousands of fossil specimens of more than one hundred species were discovered there. Many were the ancestors of modern vertebrates. "The Geiseltal is as important a fossil site as the Messel Pit near Darmstadt, which is a UNESCO World Heritage Site," says Dr. Rabi. "But because the Geiseltal collection was hardly accessible during East German times, it kind of went off the radar."

Source: Martin-Luther-University Halle-Wittenberg [March 24, 2020]

* This article was originally published here

четверг, 26 марта 2020 г.

The origins of East Asians (Wang et al. 2020 preprint)

Over at bioRxiv at this LINK. Here's the abstract: The deep population history of East Asia remains poorly understood due to a lack of ancient DNA data and sparse sampling of present-day people. We report genome-wide data from 191 individuals from Mongolia, northern China, Taiwan, the Amur River Basin and Japan dating to 6000 BCE - 1000 CE, many from contexts never previously analyzed with

* This article was originally published here

Prehistoric artefacts suggest a Neolithic era independently developed in New Guinea

New artefacts uncovered at the Waim archaeological site in the highlands of New Guinea - including a fragment of the earliest symbolic stone carving in Oceania - illustrate a shift in human behaviour between 5050 and 4200 years ago in response to the widespread emergence of agriculture, ushering in a regional Neolithic Era similar to the Neolithic in Eurasia.

Prehistoric artefacts suggest a Neolithic era independently developed in New Guinea
Excavations at New Guinea’s Waim site began in 2016 after local residents discovered these stone artefacts.
The finds included mortars, pestles, carved faces and club heads [Credit: B. Shaw]

The location and pattern of the artefacts at the site suggest a fixed domestic space and symbolic cultural practices, hinting that the region began to independently develop hallmarks of the Neolithic about 1000 years before Lapita farmers from Southeast Asia arrived in New Guinea.

While scientists have known that wetland agriculture originated in the New Guinea highlands between 8000 and 4000 years ago, there has been little evidence for corresponding social changes like those that occurred in other parts of the world.

To better understand what life was like in this region as agriculture spread, archaeologists excavated and examined a trove of artefacts from the recently identified Waim archaeological site.

"What is truly exciting is that this was the first time these artefacts have been found in the ground, which has now allowed us to determine their age with radiocarbon dating," Shaw said.

The researchers analyzed a stone carving fragment depicting the brow ridge of a human or animal face, a complete stone carving of a human head with a bird perched on top (recovered by Waim residents), and two ground stone pestle fragments with traces of yam, fruit and nut starches on their surfaces.

They also identified an obsidian core that provides the first evidence for long-distance, off-shore obsidian trade, as well as postholes where house posts may have once stood.

The findings are published in Science Advances.

Source: American Association for the Advancement of Science [March 25, 2020]

* This article was originally published here

вторник, 24 марта 2020 г.

Iron Age ‘warrior’ burial with sword and spear discovered in West Sussex

A richly-furnished grave belonging to an Iron Age ‘warrior’ buried 2,000 years ago has been uncovered in West Sussex by UCL archaeologists.

Iron Age ‘warrior’ burial with sword and spear discovered in West Sussex
The burial with weapons being excavated [Credit: UCL]
Iron weapons had been placed inside the grave, including a sword in a highly-decorated scabbard and a spear.

The burial was discovered during an excavation commissioned by Linden Homes, who are developing a site on the outskirts of Walberton, near Chichester, to create 175 new homes.

Iron Age ‘warrior’ burial with sword and spear discovered in West Sussex
The grave almost fully exposed. Note the sword in the foreground,
and the vessels to the right of the picture [Credit: UCL]
The team that made the discovery were from Archaeology South-East, the commercial branch of UCL’s Institute of Archaeology.

ASE archaeologist Jim Stevenson, who is managing the post-excavation investigations into the burial, said: “There has been much discussion generally as to who the people buried in the ‘warrior’ tradition may have been in life. Were they really warriors, or just buried with the trappings of one?

Iron Age ‘warrior’ burial with sword and spear discovered in West Sussex
Schematic plan of the grave, with the wooden container, sword, spear, 
vessels and other metal objects highlighted [Credit: UCL]
“Although the soil conditions destroyed the skeleton, the items discovered within the grave suggest that the occupant had been an important individual.”

The grave is dated to the late Iron Age/ early Roman period (1st century BC – AD 50). It is incredibly rare, as only a handful are known to exist in the South of England.

Iron Age ‘warrior’ burial with sword and spear discovered in West Sussex
Results of X-rays and initial conservation 
of the sword [Credit: UCL]
X-rays and initial conservation of the sword and scabbard reveal beautiful copper-alloy decoration at the scabbard mouth, which would have been highly visible when the sword was worn in life.

Dotted lines on the X-ray may be the remains of a studded garment worn by the occupant when buried. This is particularly exciting for the archaeologists as evidence of clothing rarely survives.

Iron Age ‘warrior’ burial with sword and spear discovered in West Sussex
Ceramic vessels placed outside of the grave aretypical 
of the 1st century AD [Credit: UCL]
The grave also held the remains of a wooden container, preserved as a dark stain, likely used to lower the individual into the grave.

Four ceramic vessels were placed outside of this container, but still within the grave. The vessels are jars made from local clays and would usually have been used for food preparation, cooking and storage. It is likely that they were placed in the grave as containers for funerary offerings, perhaps intended to provide sustenance for the deceased in the afterlife.

Archaeologists are continuing to investigate this new discovery. By looking at other burials with weapons from the same time, they hope to find out more about the identity and social status of this individual, and the local area and landscape around that time.

Source: University College London via Archaeology & Arts [March 16, 2020]

* This article was originally published here

понедельник, 23 марта 2020 г.

Fossil of 43-million-year-old penguin skin found in Argentina

Argentine researchers have announced the discovery of fossilised skin on the remains of the wing of a 43-million-year-old penguin on Marambio Island in the Antarctic. The fossil was actually discovered during a research mission in 2014.

Fossil of 43-million-year-old penguin skin found in Argentina
The fossilized skin belongs to the Palaeeudyptes gunnari, one of the many extinct types of penguins that
lived in Antarctica during the Eocene period, which lasted from around 56 to 34 million years ago
[Credit: Agencia CTyS-UNLaM]
The fossil was then studied at the La Plata Museum by Argentine paleontologist Carolina Acosta Hospitaleche, the agency for scientific disclosure at La Matanza National University said on Friday.

The fossilised skin belongs to the Palaeeudyptes gunnari, one of the many extinct types of penguins that lived in Antarctica during the Eocene period, which lasted from around 56 to 34 million years ago. At that time, Antarctica was covered in woodland and boasted a diverse fauna.

Fossil of 43-million-year-old penguin skin found in Argentina
Close-up of the fossilized skin [Credit: Agencia CTyS-UNLaM]
“The fossilization of the skin of this wing is unique because it’s the first conserved example in the world of a penguin with skin,” said Acosta Hospitaleche.

“The skin was conserved as a fossil on both surfaces of its wing, enveloping the bones that have remained articulated in their original position,” she added.

Source: AFP [March 14, 2020]

* This article was originally published here

воскресенье, 22 марта 2020 г.

Global human genomes reveal rich genetic diversity shaped by complex evolutionary history

A new study has provided the most comprehensive analysis of human genetic diversity to date, after the sequencing of 929 human genomes by scientists at the Wellcome Sanger Institute, the University of Cambridge and their collaborators. The study uncovers a large amount of previously undescribed genetic variation and provides new insights into our evolutionary past, highlighting the complexity of the process through which our ancestors diversified, migrated and mixed throughout the world.

Global human genomes reveal rich genetic diversity shaped by complex evolutionary history
Credit: Matt Midgley
The resource, published in Science, is the most detailed representation of the genetic diversity of worldwide populations to date. It is freely available to all researchers to study human genetic diversity, including studies of genetic susceptibility to disease in different parts of the world.

The consensus view of human history tells us that the ancestors of present-day humans diverged from the ancestors of extinct Neanderthal and Denisovan groups around 500,000-700,000 years ago, before the emergence of 'modern' humans in Africa in the last few hundred thousand years.

Around 50,000-70,000 years ago, some humans expanded out of Africa and soon after mixed with archaic Eurasian groups. After that, populations grew rapidly, with extensive migration and mixture as many groups transitioned from hunter-gatherers to food producers over the last 10,000 years.

This study is the first to apply the latest high-quality sequencing technology to such a large and diverse set of humans, covering 929 genomes from 54 geographically, linguistically and culturally diverse populations from across the globe. The sequencing and analysis of these genomes, which are part of the Human Genome Diversity Project (HGDP)-CEPH panel**, now provides unprecedented detail of our genetic history.

The team found millions of previously unknown DNA variations that are exclusive to one continental or major geographical region. Though most of these were rare, they included common variations in certain African and Oceanian populations that had not been identified by previous studies.

Variations such as these may influence the susceptibility of different populations to disease. However, medical genetics studies have so far predominantly been conducted in populations of European ancestry, meaning that any medical implications that these variants might have are not known. Identifying these novel variants represents a first step towards fully expanding the study of genomics to underrepresented populations.

However, no single DNA variation was found to be present in 100 per cent of genomes from any major geographical region while being absent from all other regions. This finding underlines that the majority of common genetic variation is found across the globe.

Dr Anders Bergström, of the Francis Crick Institute and an alumnus of the Wellcome Sanger Institute, said: "The detail provided by this study allows us to look deeper into human history, particularly inside Africa where less is currently known about the timescale of human evolution. We find that the ancestors of present-day populations diversified through a gradual and complex process mostly during the last 250,000 years, with large amounts of gene flow between these early lineages. But we also see evidence that small parts of human ancestries trace back to groups that diversified much earlier than this."

Hélène Blanché, Head of the Biological Resource Centre at the Centre d'Etude du Polymorphisme Humain (CEPH) in Paris, France, said: "The Human Genome Diversity Project resource has facilitated many new discoveries about human history in the past two decades. It is exciting to see that with the latest genomic sequencing technology, these genomes will continue to help us understand our species and how we have evolved."

The study also provides evidence that the Neanderthal ancestry of modern humans can be explained by just one major 'mixing event', most likely involving several Neanderthal individuals coming into contact with modern humans shortly after the latter had expanded out of Africa. In contrast, several different sets of DNA segments inherited from Denisovans were identified in people from Oceania and East Asia, suggesting at least two distinct mixing events.

The discovery of small amounts of Neanderthal DNA in west African people, most likely reflecting later genetic backflow into Africa from Eurasia, further highlights how human genetic history is characterised by multiple layers of complexity. Until recently, it was thought that only people outside sub-Saharan Africa had Neanderthal DNA.

Dr Chris Tyler-Smith, recently retired from the Wellcome Sanger Institute, said: "Though this resource is just the beginning of many avenues of research, already we can glimpse several tantalising insights into human history. It will be particularly important for better understanding human evolution in Africa, as well as facilitating medical research for the full diversity of human ancestries."

Source: Wellcome Trust Sanger Institute [March 19, 2020]

* This article was originally published here

суббота, 21 марта 2020 г.

Fine-tuning radiocarbon dating could 'rewrite' ancient events

Radiocarbon dating, invented in the late 1940s and improved ever since to provide more precise measurements, is the standard method for determining the dates of artifacts in archaeology and other disciplines.

Fine-tuning radiocarbon dating could 'rewrite' ancient events
A human femur, thought to be from medieval times, being sampled for carbon dating
[Credit: James King-Holmes/Science Photo Library]
"If it's organic and old - up to 50,000 years - you date it by radiocarbon," said Sturt Manning, the Goldwin Smith Professor of Classical Archaeology in the College of Arts and Sciences.

Manning is lead author of a new paper that points out the need for an important new refinement to the technique. The outcomes of his study, published in Science Advances, have relevance for understanding key dates in Mediterranean history and prehistory, including the tomb of Tutankhamen and a controversial but important volcanic eruption on the Greek island of Santorini.

Radiocarbon dating measures the decomposition of carbon-14, an unstable isotope of carbon created by cosmic radiation and found in all organic matter. Cosmic radiation, however, is not constant at all times. To account for fluctuations of cosmic radiation in the Earth's atmosphere, the radiocarbon content of known-age tree rings was measured backward in time from the 20th century, for thousands of years.

Tree-ring calibrated radiocarbon started to be widely used 50 years ago. A standard calibration curve was introduced in 1986 and is updated every few years as more data are added.

"A single Northern Hemisphere calibration curve has formed the basis of radiocarbon dating in Europe and the Mediterranean for five decades, setting the time frame for prehistory," Manning and co-authors write. "However, as measurement precision increases, there is mounting evidence for some small but substantive regional (partly growing season) offsets in the same-year radiocarbon levels."

In their study, Manning and co-authors question the accuracy of a single calibration curve for all of the Northern Hemisphere. Using data collected by only one lab to control for interlaboratory variation, they compared radiocarbon data from northern Europe (Germany) and from the Mediterranean (central Turkey) in the 2nd and 1st millennia B.C. They found that some small but critical periods of variation for Mediterranean radiocarbon levels exist. Data from two other radiocarbon labs on samples from central Italy and northern Turkey then provided consistency.

Growing seasons play a role, the paper says. The radiocarbon level on Earth varies according to the season; there's a winter low and a summer high, Manning said. The carbon in a tree ring reflects when the tree was photosynthesizing and, therefore, taking carbon out of the atmosphere.

"In northern Europe or in North America, a tree is going to be doing this in April through September. But a tree in Jordan or Israel does that October through April - almost the opposite time of the year," he said.

These variations, although small, potentially affect calendar dates for prehistory by up to a few decades, the paper concludes.

Even small date offsets - 50 years or less - are important for building the timeline of the Mediterranean region, which, in the last two millennia B.C., was a hotbed of interrelated cultures.

The adjusted dates confirm previously awkward timelines, where radiocarbon and history did not seem to agree for some historical landmarks, including the death and burial of Egyptian pharaoh Tutankhamen, which is dated around the 1320s to 1310s B.C., according to recent Egyptology.

The study also addresses a debate over the date of a massive volcanic eruption on Santorini. This much-studied event is dated around 1500 B.C. by archaeologists but earlier - 1630 to 1600 B.C. - by scientists. Manning said the new findings rule out the date of 1500 B.C., but may also modify the science. A 1630-1600 B.C. date remains possible, but a later date in the range 1600-1550 B.C. now becomes plausible, and even works better with existing archaeological and historical records, including writings from Egypt.

The study also has ramifications for understanding which culture influenced the Minoans and Mycenaeans, which led to ancient Greece.

"Getting the date right will rewrite and get our history correct in terms of what groups were significant in shaping what then became classical civilization," Manning said. "An accurate timeline is key to our history."

He predicts follow-up on this study and a future with more specific regional calibration curves within the Northern Hemisphere - as well as subsequent adjustment to historical dates.

Author: Kate Blackwood | Source: Cornell University [March 19, 2020]

* This article was originally published here

пятница, 20 марта 2020 г.

The Rosicrucian Egyptian Museum senet table revisited

An enigmatic ancient Egyptian game table housed in the Rosicrucian Egyptian Museum was the missing link in iconic board game evolution, according to an American ancient gaming expert.

The Rosicrucian Egyptian Museum senet table revisited
Senet table, cedar, ca. 1549-1069 BC [Credit: Rosicrucian Egyptian Museum]
Of all ancient Egyptian games, senet is probably the most well-recorded as well as popular. Known from physical objects as well as artistic representations dating from the Early Dynastic Period  (c. 3.000 BC) till the 26th Dynasty, both from Egypt itself and abroad (the Levant, Cyprus, Nubia), and associated with secular and symbolic functions, archaeologists connect senet with ideals rooted deep into the ancient Egyptian worldview. As a form, senet is known as a rectangular board divided into 30 squares in a 3 x10 allocation.

From as early as the Old Kingdom, it is represented in tomb paintings. During the New Kingdom, the game is mentioned in the Book of the Dead, as the deceased is playing against an unknown opponent, while it clearly represents the “passing” of the soul through the underworld. Representations are found in various spaces connected with eternal life; from tombs to temples. Most actual senet game boards and game boxes come from that period. Examples from the Levant and Cyprus are also of that period (corresponding to the Late Bronze Age). It is actually been stated that Cyprus has given more game tables identifiable with senet than Egypt itself.

The Rosicrucian Egyptian Museum senet table revisited
Playing field on the surface of the senet table [Credit: Rosicrucian Egyptian Museum]
The Rosicrucian Egyptian Museum senet table revisited
Side view of senet table showing legs and panel [Credit: Rosicrucian Egyptian Museum]
Despite its rich archaeological record, however, senet remains a mystery. Despite information given from Egyptian written sources (Book of the Dead mentioned above, Turin Papyrus 1.775 and especially the Great Game Text) its complete rules remain obscure. What experts can track, however, is its evolution. Earlier examples of senet, dating till the 17th Dynasty show to have a different orientation than the actual New Kingdom ones while drawings on squares become more and more complicated as we proceed into the New Kingdom. What was missing from the archaeological record was an example highlighting whether the change in orientation happened before, after or at the same pace to the change in markings.

Enter the Rosicrucian Egyptian Museum Senet Table, an out of context example acquired by San Jose California’s Rosicrucian Museum (U.S.) in 1947 through an auction in London. Previously unpublished, the object has been studied by Walter Crist, an expert in ancient gaming, who recently published it in the Journal of Egyptian Archaeology. According to Crist, the board itself is in the shape of a small table, measuring 32cm long by 13.5cm wide and 12.1cm high. A panel runs the length of the main board which, based on the orientation of the hieroglyphs on the playing face, forms the rear side of the table, while two rectangular supports running across the width of the main playing board are placed perpendicular to the panel running along with it.

Wall painting of Nefertari playing senet with an invisible opponent in her Valley of the Queens tomb
[Credit: The Yorck Project/WikiCommons]
What is more important, however, is the orientation of hieroglyphs marked on the top surface of the table (bearing the senet pattern). Here Crist observes that “the hieroglyphs are drawn so that they are upright when the board is positioned with them at the top left, with the long vertical panel at the back, indicating that the orientation of the board is that seen more commonly during the Middle Kingdom, while the hieroglyphs themselves are more typical of the Eighteenth Dynasty”.

The above element, compared with decoration in known senet examples allowed Crist to understand the importance of the Rosicrucian Senet. In fact, there were two senet examples sharing a style of hieroglyphs/markings with the Rosicrucian senet: one dating to the reign of Hatshepsut and housed at the British Museum and the other, of the era of Thutmose III, housed at the Rijksmuseum van Oudheden in Leiden (AH 34a). Still, the Rosicrucian senet differs from these two examples in one important aspect: based on its marked squares, it has the Middle Kingdom/Second Intermediate Period orientation rather than the New Kingdom one, which is found in the two Thutmosid examples above.

The above observations led the researcher to support that the senet board in the Rosicrucian Museum demonstrates a transitional stage in the pattern of decoration between the Middle Kingdom/Second Intermediate Period and the middle of the 18th Dynasty. As such, it represents the missing link in the evolution of the game from the time of Egypt’s liberation from the Hyksos up to the first Thutmosids, when it becomes more complicated before its orientation changes.

Source: Archaeology & Arts [February 11, 2020]

* This article was originally published here

COVID-19/SARS-CoV-2 open thread

When's the peak expected in your neighborhood? Do you plan to hunker down when it arrives or take your chances? If you're a Brit, how do you feel about your government's diabolical plan to have you inoculated against SARS-CoV-2 many months before a vaccine is available? It's certainly an interesting experiment, and it might just work, but at what cost? To be honest, I'm very concerned. This

* This article was originally published here

четверг, 19 марта 2020 г.

Organic molecules discovered by Curiosity Rover consistent with early life on Mars

Organic compounds called thiophenes are found on Earth in coal, crude oil and oddly enough, in white truffles, the mushroom beloved by epicureans and wild pigs.

Organic molecules discovered by Curiosity Rover consistent with early life on Mars
Credit: NASA/JPL-Caltech
Thiophenes were also recently discovered on Mars, and Washington State University astrobiologist Dirk Schulze-Makuch thinks their presence would be consistent with the presence of early life on Mars.

Schulze-Makuch and Jacob Heinz with the Technische Universitat in Berlin explore some of the possible pathways for thiophenes' origins on the red planet in a new paper published in the journal Astrobiology. Their work suggests that a biological process, most likely involving bacteria rather than a truffle though, may have played a role in the organic compound's existence in the Martian soil.

"We identified several biological pathways for thiophenes that seem more likely than chemical ones, but we still need proof," Dirk Schulze-Makuch said. "If you find thiophenes on Earth, then you would think they are biological, but on Mars, of course, the bar to prove that has to be quite a bit higher."

Thiophene molecules have four carbon atoms and a sulfur atom arranged in a ring, and both carbon and sulfur, are bio-essential elements. Yet Schulze-Makuch and Heinz could not exclude non-biological processes leading to the existence of these compounds on Mars.

Meteor impacts provide one possible abiotic explanation. Thiophenes can also be created through thermochemical sulfate reduction, a process that involves a set of compounds being heated to 248 degrees Fahrenheit (120 degrees Celsius) or more.

In the biological scenario, bacteria, which may have existed more than three billion years ago when Mars was warmer and wetter, could have facilitated a sulfate reduction process that results in thiophenes. There are also other pathways where the thiophenes themselves are broken down by bacteria.

While the Curiosity Rover has provided many clues, it uses techniques that break larger molecules up into components, so scientists can only look at the resulting fragments.

Further evidence should come from the next rover, the Rosalind Franklin, which is expected to launch in July 2020. It will be carrying a Mars Organic Molecule Analyzer, or MOMA, which uses a less destructive analyzing method that will allow for the collection of larger molecules.

Schulze-Makuch and Heinz recommend using the data collected by the next rover to look at carbon and sulfur isotopes. Isotopes are variations of the chemical elements that have different numbers of neutrons than the typical form, resulting in differences in mass.

"Organisms are 'lazy'. They would rather use the light isotope variations of the element because it costs them less energy," he said.

Organisms alter the ratios of heavy and light isotopes in the compounds they produce that are substantially different from the ratios found in their building blocks, which Schulze-Makuch calls "a telltale signal for life."

Yet even if the next rover returns this isotopic evidence, it may still not be enough to prove definitively that there is, or once was, life on Mars.

"As Carl Sagan said 'extraordinary claims require extraordinary evidence,'" Schulze-Makuch said. "I think the proof will really require that we actually send people there, and an astronaut looks through a microscope and sees a moving microbe."

Source: Washington State University [March 06, 2020]

* This article was originally published here

среда, 18 марта 2020 г.

What other planets can teach us about Earth

Sometimes, you need to leave home to understand it. For Stanford planetary geologist Mathieu Lapôtre, "home" encompasses the entire Earth.

What other planets can teach us about Earth
A composite image shows Earth from the vantage point of a spacecraft in orbit around our planet’s
moon in October 2015 [Credit: NASA/Goddard/Arizona State University]
"We don't only look at other planets to know what's out there. It's also a way for us to learn things about the planet that's under our own feet," said Lapôtre, an assistant professor of geological sciences in the School of Earth, Energy, & Environmental Sciences (Stanford Earth).

Scientists since Galileo have sought to understand other planetary bodies through an earthly lens. More recently, researchers have recognized planetary exploration as a two-way street. Studies of space have helped to explain aspects of climate and the physics of nuclear winter, for example. Yet revelations have not permeated all geoscience fields equally. Efforts to explain processes closer to the ground—at Earth's surface and deep in its belly—are only beginning to benefit from knowledge gathered in space.

Now, as telescopes acquire more power, exoplanet studies grow more sophisticated and planetary missions produce new data, there's potential for much broader impacts across Earth sciences, as Lapôtre and co-authors from Arizona State University, Harvard University, Rice University, Stanford and Yale University argue in the journal Nature Reviews Earth & Environment.

"The multitude and variety of planetary bodies within and beyond our solar system," they write in a paper published March 2, "might be key to resolving fundamental mysteries about the Earth."

In the coming years, studies of these bodies may well alter the way we think about our place in the universe.

Alien forms

Observations from Mars have already changed the way scientists think about the physics of sedimentary processes on Earth. One example got underway when NASA's Curiosity Rover crossed a dune field on the red planet in 2015.

"We saw that there were big sand dunes and small, decimeter-scale ripples like the ones we see on Earth," said Lapôtre, who worked on the mission as a Ph.D. student at Caltech in Pasadena, Calif. "But there was also a third type of bedform, or ripple, that does not exist on Earth. We couldn't explain how or why this shape existed on Mars."

What other planets can teach us about Earth
Ripples formed by wind atop a sand dune in Gale Crater on Mars offer an analog for understanding
 the conditions that created ancient ripples and dunes on Earth
[Credit: NASA/JPL-Caltech/MSSS]
The strange patterns prompted scientists to revise their models and invent new ones, which ultimately led to the discovery of a relationship between the size of a ripple and the density of the water or other fluid that created it. "Using these models developed for the environment of Mars, we can now look at an old rock on Earth, measure ripples in it and then draw conclusions about how cold or salty the water was at the time the rock formed," Lapôtre said, "because both temperature and salt affect fluid density."

This approach is applicable across the geosciences. "Sometimes when exploring another planet, you make an observation that challenges your understanding of geological processes, and that leads you to revise your models," Lapôtre explained.

Planets as experiments

Other planetary bodies can also help to show how frequent Earth-like bodies are in the universe and what, exactly, makes Earth so different from the average planet.

"By studying the variety of outcomes that we see on other planetary bodies and understanding the variables that shape each planet, we can learn more about how things might have happened on Earth in the past," explained co-author Sonia Tikoo-Schantz, a geophysics professor at Stanford Earth whose research centers on paleomagnetism.

Consider, she suggested, how studies of Venus and Earth have helped scientists better understand plate tectonics. "Venus and Earth are about the same size, and they probably formed under fairly similar conditions," Tikoo-Schantz said. But while Earth has tectonic plates moving around and abundant water, Venus has a mostly solid lid, no water on its surface and a very dry atmosphere.

What other planets can teach us about Earth
Unlike Earth, Venus has a mostly solid lid, no water on its surface
and a very dry atmosphere [Credit: NASA/JPL]
"From time to time, Venus has some kind of catastrophic disruption and a resurfacing of much of the world," Tikoo-Schantz said, "but we don't see this continuous steady state tectonic environment that we have on Earth."

Scientists are increasingly convinced that water may explain much of the difference. "We know that subduction of tectonic plates brings water down into the Earth," Tikoo-Schantz said. "That water helps lubricate the upper mantle, and helps convection happen, which helps drive plate tectonics."

This approach—using planetary bodies as grand experiments—can be applied to answer more questions about how Earth works. "Imagine you want to see how gravity might affect certain processes," Lapôtre said. "Going to other planets can let you run an experiment where you can observe what happens with a lower or higher gravity—something that's impossible to do on Earth."

Core paradox

Studies measuring magnetism in ancient rocks suggest that Earth's magnetic field has been active for at least 3.5 billion years. But the cooling and crystallization of the inner core that scientists believe sustains Earth's magnetic field today started less than 1.5 billion years ago. This 2-billion-year gap, known as the new core paradox, has left researchers puzzling over how Earth's dynamo could have started so early, and persisted for so long. Answers may lie in other worlds.

"In our circle of close neighbors—the Moon, Mars, Venus—we're the only planet with a magnetic field that's been going strong since the beginning and remains active today," Lapôtre said. But Jupiter-sized exoplanets orbiting close to their star have been identified with magnetic fields, and it may soon be technically feasible to detect similar fields on smaller, rocky, Earth-like worlds. Such discoveries would help clarify whether Earth's long-lived dynamo is a statistical anomaly in the universe whose startup required some special circumstance.

Ultimately, the mystery around the origin and engine behind Earth's dynamo is a mystery about what creates and sustains the conditions for life. Earth's magnetic field is essential to its habitability, protecting it against dangerous solar winds that can strip a planet of water and atmosphere. "That's part of why Mars is such a dry desert compared to Earth," Tikoo-Schantz said. "Mars started to dehydrate when its magnetic field died."

Earth everchanging

Much of the impetus to look far beyond Earth when trying to decode its inner workings has to do with our planet's restless nature. At many points in its 4.5 billion-year existence, Earth looked nothing like the blue-green marble it is today.

What other planets can teach us about Earth
Night-side view of magnetic field lines in a simulation of a “hot Jupiter” exoplanet. Simulations like these help
researchers better understand the interior dynamics of these planets and learn more about how they may
have formed. Magenta indicates magnetic fields with positive polarity, and blue indicates fields
 with negative polarity [Credit: Tamara Rogers, Jess Vriesema, University of Arizona]
"We're trying to get to the point where we can characterize planets that are like the Earth, and hopefully, someday find life on one of them," said co-author Laura Schaefer, a planetary scientist at Stanford Earth who studies exoplanets. Chances are it will be something more like bacteria than E.T., she said.

"Just having another example of life anywhere would be amazing," Schaefer said. It would also help to illuminate what happened on Earth during the billions of years before oxygen became abundant and, through processes and feedback loops that remain opaque, complex life burst forth.

"We're missing information from different environments that existed on the surface of the Earth during that time period," Schaefer explained. Plate tectonics constantly recycles rocks from the surface, plunging them into the planet's fiery innards, while water sloshing around oceans, pelting down from rainclouds, hanging in the air, and slipping in rivers and streams tends to alter the geochemistry of rocks and minerals that remain near the surface.

Earth's very liveliness makes it a poor archive for evidence of life and its impacts. Other planetary bodies—some of them dead still and bone dry, others somehow akin to the ancient Earth—may prove better suited to the task.

That's part of why scientists were so excited to find, in 2019, that a rock sample collected by the Apollo 14 astronauts in 1971 may in fact hold minerals that rocketed off of Earth as a meteorite billions of years ago. "On the Moon, there is no plate tectonics or aqueous weathering," Lapôtre said. "So this piece of rock has been sitting there intact for the last few billion years just waiting for us to find it."

To be sure, planetary scientists do not expect to find many ancient Earth time capsules preserved in space. But continued exploration of other worlds in our solar system and beyond could eventually yield a small statistical sample of planets with life on them—not carbon copies of Earth's systems, but systems nonetheless where interactions between life and atmosphere can come into sharper focus.

"They're not going to be at the same stage of life as we have today on Earth, and so we'll be able to learn about how planets and life evolve together," Schaefer said. "That would be pretty revolutionary."

Author: Josie Garthwaite | Source: Stanford University [March 05, 2020]

* This article was originally published here