Monday, July 30, 2012
Human behavior, as we know it, emerged earlier than previously thought
The Later Stone Age emerged in South Africa more than 20,000 years earlier than previously believed -- about the same time humans were migrating from Africa to the European continent, says a new international study led by the University of Colorado Boulder.
The study shows the onset of the Later Stone Age in South Africa likely began some 44,000 to 42,000 years ago, said Paola Villa, a curator at the University of Colorado Museum of Natural History and lead study author. The new dates are based on the use of precisely calibrated radiocarbon dates linked to organic artifacts found at Border Cave in the Lebombo Mountains on the border of South Africa and Swaziland containing evidence of hominid occupation going back 200,000 years.
The Later Stone Age is synonymous to many archaeologists with the Upper Paleolithic Period, when modern humans moved from Africa into Europe roughly 45,000 years ago and spread rapidly, displacing and eventually driving Neanderthals to extinction. The timing of the technological innovations and changes in the Later Stone Age in South Africa are comparable to that of the Upper Paleolithic, said Villa.
"Our research proves that the Later Stone Age emerged in South Africa far earlier than has been believed and occurred at about the same time as the arrival of modern humans in Europe," said Villa. "But differences in technology and culture between the two areas are very strong, showing the people of the two regions chose very different paths to the evolution of technology and society."
A companion paper published in PNAS and led by d'Errico reports on organic materials found at Border Cave dating to the Later Stone Age, an indication that the San hunter-gatherer culture first thought to have begun about 20,000 years ago in the region probably emerged as early as 44,000 years ago, said Villa.
Organic artifact assemblages at Border Cave dating to the Later Stone Age included ostrich eggshell beads, thin bone arrowhead points, wooden digging sticks, a gummy substance called pitch that was used to haft, or attach, bone and stone blades to shafts and a lump of beeswax likely used for hafting. The assemblage also included worked tusks of members of the pig family, which likely were used to plane wood, and notched bones that may have been used for counting.
A wooden digging stick from Border Cave dated to about 40,000 years ago was found in association with bored but broken stones likely used to weight such sticks. The sticks and stone weights are similar to digging implements used by women of the prehistoric San hunter-gatherer culture in the region to unearth bulbs and termite larvae, a practice that continued into historic times, said Villa. "These digging sticks from Border Cave are the oldest artifacts of this kind known from South Africa or anywhere else in Africa."
The new PNAS study led by Villa also indicates big changes were occurring in hunting technology during the Later Stone Age at Border Cave, said Villa. They included a shift from spears hafted with stone points -- the main hunting weapon in the Middle Stone Age -- to the likely use of the bow and arrow, a technology that included very thin bone points that probably were tipped with poison, she said.
"The very thin bone points from the Later Stone Age at Border Cave are good evidence for bow and arrow use," said Villa. "The work by d'Errico and colleagues shows that the points are very similar in width and thickness to the bone points produced by San culture that occupied the region in prehistoric times, whose people were known to use bows and arrows with poison-tipped bone points as a way to bring down medium and large-sized herbivores."
Chemical analyses showed the poison used with such bone points was most likely ricinoleic acid, which can be derived from the seeds of castor oil plants and which has been identified as being used in South Africa at least 24,000 years ago. "Such bone points could have penetrated thick hides, but the lack of 'knock-down' power means the use of poison probably was a requirement for successful kills," said Villa.
The lump of beeswax from Border Cave also dating to about 40,000 years ago -- the oldest known beeswax used by humans ever discovered -- was wrapped in plant fibers that may have been similar to fibers used to make the strings for hunting bows, said Villa.
While stone tools continued to be manufactured in the Later Stone Age at Border Cave, stone spear points from the Middle Stone Age gave way to tiny, thin flakes known as microliths that were probably hafted on shafts, much like the bone points, with pitch made from the bark of a common type of coniferous tree found in the region.
While a 2011 study co-authored by Villa and Wil Roebroeks of Leiden University in the Netherlands showed that Neanderthals mastered the manufacture of pitch in Europe 200,000 years ago, it was not a particularly simple task since the process involved burning peeled bark in the absence of air, said Villa. The Later Stone Age inhabitants of South Africa probably dug holes into the ground and inserted bark peels, then lit them on fire and covered the holes tightly with stones. "This is the first time pitch-making is demonstrated in South Africa," said Villa.
The Upper Paleolithic Period in Europe that corresponds to the Later Stone Age in South Africa also spurred complex new technologies that helped humans survive and thrive in much different environments. Artifacts from the Upper Paleolithic included spear-throwers, bone needles with eyelets for sewing furs, bone fishing hooks, bone flutes and even ivory figurines carved from mammoth tusks.
Villa said that a fundamental rearrangement of human behavior that had its beginnings 50,000-60,000 years ago in Africa and spread to Europe -- an idea first proposed by Stanford University archaeologist Richard Klein -- appears quite plausible.
"The dating and analysis of archaeological material discovered at Border Cave in South Africa, has allowed us to demonstrate that many elements of material culture that characterise the lifestyle of San hunter-gatherers in southern Africa, were part of the culture and technology of the inhabitants of this site 44,000 years ago," says Backwell.
A key question in human evolution is when in prehistory human cultures similar to ours emerged? Until now, most archaeologists believed that the oldest traces of San hunter-gatherer culture in southern Africa dates back 10,000, or at most 20,000 years.
The international team of researchers, led by Francesco d'Errico, Director of Research at the French National Research Centre, dated and directly analysed objects from archaeological layers at Border Cave.
Located in the foothills of the Lebombo Mountains in KwaZulu-Natal, South Africa, the site has yielded exceptionally well-preserved organic material.
Backwell says their results have shown without a doubt that at around 44,000 years ago the people at Border Cave were using digging sticks weighted with perforated stones, like those traditionally used by the San.
"They adorned themselves with ostrich egg and marine shell beads, and notched bones for notational purposes. They fashioned fine bone points for use as awls and poisoned arrowheads. One point is decorated with a spiral groove filled with red ochre, which closely parallels similar marks that San make to identify their arrowheads when hunting," says Backwell.
Chemical analysis of residues on a wooden stick decorated with incisions reveals that, like San objects used for the same purpose, it was used to hold and carry a poison containing ricinoleic acid found in castor beans. This represents the earliest evidence for the use of poison.
A lump of beeswax, mixed with the resin of toxic Euphorbia, and possibly egg, was wrapped in vegetal fibres made from the inner bark of a woody plant. "This complex compound used for hafting arrowheads or tools, directly dated to 40,000 years ago, is the oldest known evidence of the use of beeswax," says Backwell.
Warthog tusks were shaped into awls and possibly spear heads. The use of small pieces of stone to arm hunting weapons is confirmed by the discovery of resin residue still adhering to some of the tools, which chemical analysis has identified as a suberin (waxy substance) produced from the sap of Podocarpus (yellowwood) trees.
The study of stone tools discovered in the same archaeological layers as the organic remains, and from older deposits, shows a gradual evolution in stone tool technology. Organic artifacts, unambiguously reminiscent of San material culture, appear relatively abruptly, highlighting an apparent mismatch in rates of cultural change. This finding supports the view that what we perceive today as "modern behaviour" is the result of non-linear trajectories that may be better understood when documented at a regional scale.
Link to Isaiah 10:9-10?
A beautiful and colossal human sculpture is one of the latest cultural treasures unearthed by an international team at the Tayinat Archaeological Project (TAP) excavation site in southeastern Turkey. A large semi-circular column base, ornately decorated on one side, was also discovered. Both pieces are from a monumental gate complex that provided access to the upper citadel of Kunulua, capital of the Neo-Hittite Kingdom of Patina (ca. 1000-738 BC).
The head and torso of the human figure, intact to just above its waist, stands approximately 1.5 meters in height, suggesting a total body length of 3.5 to four meters. The figure’s face is bearded, with beautifully preserved inlaid eyes made of white and black stone, and its hair has been coiffed in an elaborate series of curls aligned in linear rows. Both arms are extended forward from the elbow, each with two arm bracelets decorated with lion heads. The figure’s right hand holds a spear, and in its left is a shaft of wheat. A crescent-shaped pectoral adorns its chest. A lengthy Hieroglyphic Luwian inscription, carved in raised relief across its back, records the campaigns and accomplishments of Suppiluliuma, likely the same Patinean king who faced a Neo-Assyrian onslaught of Shalmaneser III as part of a Syrian-Hittite coalition in 858 BC. Credit: Jennifer Jacksonthe Bronze Age at the end of the second millennium BC."
"These newly discovered Tayinat sculptures are the product of a vibrant local Neo-Hittite sculptural tradition," said Professor Tim Harrison, the Tayinat Project director and professor of Near Eastern Archaeology in the University of Toronto's Department of Near and Middle Eastern Civilizations. "They provide a vivid glimpse into the innovative character and sophistication of the Iron Age cultures that emerged in the eastern Mediterranean following the collapse of the great imperial powers of the Bronze Age at the end of the second millennium BC."
The second sculpture is a large semi-circular column base, approximately one metre in height and 90 centimetres in diameter, lying on its side next to the human figure. A winged bull is carved on the front of the column and it is flanked by a sphinx on its left. The right side of the column is flat and undecorated, an indication that it originally stood against a wall.
"The two pieces appear to have been ritually buried in the paved stone surface of the central passageway through the Tayinat gate complex," said Harrison. The complex would have provided a monumental ceremonial approach to the upper citadel of the royal city. Tayinat, a large low-lying mound, is located 35 kilometres east of Antakya (ancient Antioch) along the Antakya-Aleppo road.
The presence of colossal human statues, often astride lions or sphinxes, in the citadel gateways of the Neo-Hittite royal cities of Iron Age Syro-Anatolia continued a Bronze Age Hittite tradition that accentuated their symbolic role as boundary zones, and the role of the king as the divinely appointed guardian or gate keeper of the community. By the ninth and eighth centuries BC, these elaborately decorated gateways, with their ornately carved reliefs, had come to serve as dynastic parades, legitimizing the power of the ruling elite. The gate reliefs also formed linear narratives, guiding their audiences between the human and divine realms, with the king serving as the link between the two worlds.
The Tayinat gate complex appears to have been destroyed following the Assyrian conquest of the region in 738 BC, when the area was paved over and converted into the central courtyard of an Assyrian sacred precinct. These smashed and deposited monumental sculptures also include a magnificently carved lion that was discovered last year and Hieroglyphic Luwian-inscribed stelae (stone slabs or pillars used for commemoratives purposes). Together these finds hint of an earlier Neo-Hittite complex that might have once faced the gateway approach.
Scholars have long speculated that the reference to Calno, identified as one of the "kingdoms of the idols" in Isaiah's oracle against Assyria (Isaiah 10:9-10), alludes to the Assyrian devastation of Kunulua (i.e., Tayinat). The destruction of the Luwian monuments and conversion of the area into an Assyrian religious complex may represent the physical manifestation of this historic event, subsequently memorialized in Isaiah's oracle.
Saturday, July 28, 2012
Archeologists have discovered large jars filled with 3,300-year-old burnt wheat at the excavation sites of the Tel Hatzor National Park in the Upper Galilee.
“Hatzor flourished during the Middle Canaanite period (1,750 BCE) and during the Israelite period (900 BCE), and generated the biggest fortified complex in Israel during this period,” said Dr. Zvika Tsuk, chief archeologist of the INPA.
“The city was one of the most important towns for the duration of the Fertile Crescent, maintaining trade relations with cities in Babylon and Syria, and substantial quantities of tin for the bronze industry were sent to the city...”
“The water system built at Hatzor is one of the largest and most amazing that have been exposed in the country, and everyone who continues to explore the site finds more and more secrets and details about our past in Israel,” he added.
Monday, July 23, 2012
Few ancient sites in the Holy Land have ignited the imagination like the lost tombs of the Maccabees, the family that led a Jewish rebel army to victory against Seleucid religious repression in the second century BCE.
Beginning more than 140 years ago, travelers, clergymen and enthusiastic scholars of varying levels of religious fervor and competence have been looking for the tomb site – described in contemporary sources as a magnificent Hellenistic monument that included pyramids and ships of carved stone and could be seen by sailors on the Mediterranean Sea, 18 miles away. The complex was one of the greatest man-made landmarks in ancient Judea.
No trace of it has ever been found.
For the early archaeologists who arrived in Ottoman Palestine with shovels, Bibles, and a thirst for the physical traces of the events described in Scripture, the tombs were a tantalizing mystery. More than a century later, so they remain.
Today, archaeologists have their eyes on a site that might — just might — provide an answer. Read more here (fascinating article.)
This fascinating find is the first of its kind, says Prof. Oren Tal, director of the excavation and Chairman of TAU's Department of Archaeology and Ancient Near Eastern Cultures. "The scientific value is unprecedented. This is the first hoard of gold coins that we have in Israel that we can date to the Crusader period."
Prof. Tal believes that the coins provide an important clue to how large-scale economic transactions were made in the Crusader period. "They were not afraid to use older coins in order to complete large transactions and run large-scale businesses," he said, indicating that this "pot of gold" may be one of a group hidden in the castle, remnants of Arsur's role as a business center where industrial and agricultural goods were traded.
According to Prof. Tal, the discovery adds to the debate over gold circulation during the time of the Crusades, a series of military incursions into the region to establish Christianity. It puts Fatimid-period coins, minted by Egyptian Sultans in the 10th and 11th centuries, in a Crusader context. Their use of gold from an earlier period is somewhat surprising, given the importance placed on coin minting.
Typically, societies mint their own coins, especially for the completion of large transactions, because it impacts more than just economics — it has marketing and public relations value. From a social and political standpoint, the minting of coins shows that a culture has the wealth and ability to make its own currency, feeding into a sense of independence as a people, cultural self-definition, and a collective identity, explains Prof. Tal.
Though historically priceless, the actual cash value of the coins is difficult to pin down, says Prof. Tal. A document found in the Cairo Genizah hints at the worth of the hoard, suggesting that two gold dinars, the face value on the coins that were found, can provide sufficiently for an extended family for one month.
Assuming the extended family includes a father, mother, sons, daughters, and their spouses and children, this could include 12 to 24 people. If 20 people can make their living for a month on two gold coins, the horde that was discovered could sustain 50 families for 30 days, or five families for approximately one year, all depending on the standard of living.
Arsur is a perfect time capsule due to its short period of occupation, says Prof. Tal. The findings from the castle, which in addition to the coins include items such as pottery, glass and metal objects, arrowheads, and catapult stones, are a window into a specific historical period. They help researchers to develop a working knowledge of the material culture of the Crusaders, and provide clues to interactions between the Islamic and Christian worlds.
The seigniory of Arsur was leased to the Military Order of the Hospitallers in 1261. The Order originally arrived in the Holy Land in the 12th century as a group of orderlies serving European pilgrims. As evidenced by their use of the castle as a storage place for their profits, Arsur was one of their most important strongholds. In 1265, the castle was attacked by the Egyptian Sultan Baybars, and after withstanding a 40-day siege, the castle was eventually conquered. It has remained uninhabited since then.
In archaeological excavations the Israel Antiquities Authority is conducting at the foot of Akko’s southern seawall, installations were exposed that belong to a harbor that was operating in the city already in the Hellenistic period (third-second centuries BCE) and was the most important port in Israel at that time.
Among the finds there: large mooring stones that were incorporated in the quay, which were used to secure sailing vessels.
A mooring stone that was incorporated in the quay. There was a hole in the stone in which the mooring/anchoring rope was inserted
The finds were discovered during the course of archaeological excavations being carried out as part of the seawall conservation project undertaken by the Old Akko Development Company and underwritten by the Israel Lands Administration.
The first evidence indicating the possible existence of this quay was in 2009 when a section of pavement was discovered comprised of large kurkar flagstones dressed in a technique reminiscent of the Phoenician style that is characteristic of installations found in a marine environment. This pavement, which was discovered underwater, raised many questions amongst archaeologists. Besides the theory that this is a quay, some suggested this was the floor of a large building.
According to Kobi Sharvit, director of the Marine Archaeology Unit of the Israel Antiquities Authority, “Among the finds we’ve discovered now are large mooring stones that were incorporated in the quay and were used to secure sailing vessels that anchored in the harbor c. 2,300 years ago. This unique and important find finally provides an unequivocal answer to the question of whether we are dealing with port installations or the floor of a building. In addition, we exposed collapse comprised of large dressed stones that apparently belonged to large buildings or installations, which was spread of a distance of dozens of meters. What emerges from these finds is a clear picture of systematic and deliberate destruction of the port facilities that occurred in antiquity”.
Sharvit adds, “Recently a find was uncovered that suggests we are excavating part of the military port of Akko. We are talking about an impressive section of stone pavement c. 8 meters long by c. 5 meters wide that was partially exposed. The floor is delimited on both sides by two impressive stone walls that are also built in the Phoenician manner. It seems that the floor between the walls slopes slightly toward the south, and there was a small amount of stone collapse in its center. Presumably this is a slipway, an installation that was used for lifting boats onto the shore, probably warships in this case”. According to Sharvit, “Only further archaeological excavations will corroborate or invalidate this theory”.
The bottom of the ancient harbor was exposed at the foot of the installations. There the mooring stones were found as well as thousands of fragments of pottery vessels, among which are dozens of intact vessels and metallic objects. The preliminary identification of the pottery vessels indicates that many of them come from islands in the Aegean Sea, including Knidos, Rhodes, Kos and others, as well as other port cities located along the Mediterranean coast.
An imported bowl characteristic of the Hellenistic period. The bowl was found in a layer of harbor sludge. This layer contained thousands of intact pottery vessels, potsherds, etc.
These finds constitute solid archaeological evidence regarding the location of the Hellenistic harbor and perhaps the military port. According to Sharvit, “It should be understood that until these excavations the location of this important harbor was not clear. Remains of it were found at the base of the Tower of Flies and in the region of the new marina in excavations conducted in the early 1980s by the late Dr. Elisha Linder and the late Professor Avner Raban. But now, for the first time, parts of the harbor are being discovered that are adjacent to the ancient shoreline and the Hellenistic city. Unfortunately, parts of the quay continue beneath the Ottoman city wall – parts that we will probably not be able to excavate in the future.
Nevertheless, in those sections of the harbor that extend in the direction of the sea and the modern harbor the excavation will continue in an attempt to learn about the extent of the ancient harbor, and to try and clarify if there is a connection between the destruction in the harbor and the destruction wrought by Ptolemy in 312 BCE, the destruction that was caused by the Hasmonean uprising in 167 BCE or by some other event.
Thursday, July 12, 2012
Who were the first humans to enter the North American continent? Were they humans who founded what is known as the Clovis culture over 13,000 years ago? Or did other, totally unrelated peoples precede the Clovis immigrants? This issue has been intensely, if not bitterly debated for decades. The Clovis culture has been seen as the cradle of North American indigenous culture. Now new international research shows that people of another culture and technology were present concurrently or even previous to those of Clovis. Scientists have added a new and dramatic chapter to the history of the peopling of the Americas striking a deadly blow to the "Clovis First" theory that has dominated pre-historic American archaeology for so long. The sensational results are published in the international journal Science.
Evidence that a non-Clovis culture was present in North America at least as early as Clovis people themselves and likely before is presented by an international team of researchers from the USA, the UK, and Denmark.
Archeological excavations at the Paisley Caves in south-central Oregon were led by Dr. Dennis Jenkins from the University of Oregon.
Dr. Loren Davis of Oregon State University mapped the stratigraphy and studied the site formation processes.
Dr. Paula Campos and Professor Eske Willerslev from the Centre for GeoGenetics at the University of Copenhagen, Denmark, profiled the many DNA finds from the caves.
Dr. Thomas Stafford, Jr., also from Centre of GeoGenetics, was in charge of the radiocarbon geochronology and biogeochemistry.
The evidence for a pre-13,000 year old non-Clovis culture in North America includes obsidian and chert artifacts known as Western Stemmed projectile points, and DNA-profiling of dried human excrement — more accurately known as coprolites. Both obsidian projectile points and coprolites were excavated from sediments in the Paisley Caves.
Previous investigations found that human coprolites in the caves predated the Clovis culture by over 1,000 years; however, critics questioned the interpretations by saying that the cave strata had not been sufficiently examined and that no Clovis-age stone tools had been found with the coprolites.
Critics also questioned whether or not younger DNA could have been washed down through the cave's sediments, thereby contaminating non-human coprolites with more recent human DNA. If true, evidence for pre-Clovis human presence would have been bogus.
The new study refutes every one of the critics' arguments and uses overwhelming archaeological, stratigraphic, DNA and radiocarbon evidence to conclusively state that humans — and ones totally unrelated to Clovis peoples — were present at Paisley Caves over a millennium before Clovis.
Rocking the theoretical boat
The new results severely contrast with the "Clovis First" theory for early peopling of the Americas. The Clovis First hypothesis states that no humans existed in the Americas prior to Clovis, which dates from 13,000 years ago, and that the distinct Clovis lithic technology is the mother technology of all other stone artifact types later occurring in the New World.
This theory has been predominant since the first evidence of human presence in America was found in 1932 at the Clovis type locality in Blackwater Draw, just outside the village of Clovis in New Mexico. But now this praised and respected foundation of American prehistory has been overthrown.
Dr. Jenkins says of the paradigm shifting results:
"One of the central questions has been whether the technological evolution of hunting tools such as dart and spearheads can be attributed solely to the Clovis culture and the knowledge that these people brought from the Old World. During our excavations in the Paisley Caves we've found a completely different type of dart points. But these new points are of a completely different construction from those found in the Clovis culture. As our radiocarbon dating shows, the new finds are as old, or possibly older than the Clovis finds, which proves that the Clovis culture cannot have been the 'Mother technology' for all other technologies in America. Our results show that America was colonized by multiple cultures at the same time. And some perhaps even earlier than Clovis."
Human excreta rewrite history
It's not the first time that the partners Dr. Jenkins from the US and Professor Willerslev from Denmark rewrite American prehistory.
In 2008, the two researchers presented a DNA-profiling's and radiocarbon dating of coprolites moving the first human settlements in North America back in time by one thousand years, from 13,000 to 14,340 years ago. As if that was not enough, the team showed through DNA analysis of ancient human excrement that these people originated in Asia and were the probable predecessors of modern indigenous Americans.
With the new results the international team has added an important piece to the puzzle of who peopled the Americas — the final continent on Earth to be colonized by humans.
Professor Willerslev says of the new results:
"Our investigations constitute the final blow to the Clovis First theory. Culturally, biologically and chronologically the theory is no longer viable. The dissimilar stone artefacts, as well as the DNA-profiling of the human excrement, show that humans were present before Clovis and that another culture in North America was at least as old as the Clovis Culture itself. Or to put it differently: Either America was populated several thousand years before Clovis by people who created 'mother' technologies to the two very different styles of Clovis tools and Western Stemmed Tradition tools. Or else there must have been two earlier migrations into North America of which one must have predated the Clovis immigration by at least one thousand years. Both assumptions would explain our findings, but trying to distinguish which is more likely is very premature."
Dr Paula Campos, a former postdoc at Willerslev's lab in Copenhagen, now at Science Museum, University of Coimbra, Portugal, elaborates the point:
"When we published the first DNA results from the Paisley Caves four years ago it caused an outcry. Many archaeologists felt that our results must be wrong. They considered it an established fact that Clovis were the first Americans. People would come up with any number of alternative explanations to our data in order to repudiate our interpretation. Today we demonstrate that our conclusions were right."
Thomas Stafford, also of the Centre for GeoGenetics in Copenhagen, and Loren Davies of Oregon State University agree:
"Critics said that the stratigraphy in the Paisley Caves is diffuse and chaotic and that this explains the finding of human coprolites older that Clovis. This couldn't be more wrong. The stratigraphy is well developed, clear and ordered correctly top to bottom."
Tom Stafford elaborates:
"No other archaeological site in the US has been as thoroughly and exhaustively dated as the Paisley Caves. We've completed more than 141 new radiocarbon measurements on materials ranging from coprolites to wood and plant artefacts, fossil plants and mummified animals, to unique, water soluble chemical fractions from sediments and the coprolites themselves. We have used 14C dating to physically and temporally dissect the Paisley Caves strata at the millimetre l level. At present, we see no evidence that geologically younger, water-borne molecules — DNA in particular — have moved downward and contaminated deeper, older coprolites. The aDNA and 14C data are iterative and corroborate each other. Our conclusion is that humans were present in North America at least one thousand years before Clovis and that these earlier peoples probably had no technological or genetic similarity to the iconic Clovis Culture. The Clovis First debate has ended. The theory is now dead and buried."
Wednesday, July 11, 2012
Scientists have found that Native American populations — from Canada to the southern tip of Chile — arose from at least three migrations, with the majority descended entirely from a single group of First American migrants that crossed over through Beringia, a land bridge between Asia and America that existed during the ice ages, more than 15,000 years ago.
By studying variations in Native American DNA sequences, the international team found that while most of the Native American populations arose from the first migration, two subsequent migrations also made important genetic contributions. The paper is published in the journal Nature today.
"For years it has been contentious whether the settlement of the Americas occurred by means of a single or multiple migrations from Siberia," said Professor Andres Ruiz-Linares (UCL Genetics, Evolution and Environment), who coordinated the study. "But our research settles this debate: Native Americans do not stem from a single migration. Our study also begins to cast light on patterns of human dispersal within the Americas."
In the most comprehensive survey of genetic diversity in Native Americans so far, the team took data from 52 Native American and 17 Siberian groups, studying more than 300,000 specific DNA sequence variations called Single Nucleotide Polymorphisms to examine patterns of genetic similarities and differences between the population groups.
The second and third migrations have left an impact only in Arctic populations that speak Eskimo-Aleut languages and in the Canadian Chipewyan who speak a Na-Dene language. However, even these populations have inherited most of their genome from the First American migration. Eskimo-Aleut speakers derive more than 50% of their DNA from First Americans, and the Chipewyan around 90%. This reflects the fact that these two later streams of Asian migration mixed with the First Americans they encountered after they arrived in North America.
"There are at least three deep lineages in Native American populations," said co-author David Reich, Professor of genetics at Harvard Medical School. "The Asian lineage leading to First Americans is the most anciently diverged, whereas the Asian lineages that contributed some of the DNA to Eskimo–Aleut speakers and the Na-Dene-speaking Chipewyan from Canada are more closely related to present-day East Asian populations."
The team also found that once in the Americas, people expanded southward along a route that hugged the coast with populations splitting off along the way. After divergence, there was little gene flow among Native American groups, especially in South America.
Two striking exceptions to this simple dispersal were also discovered. First, Central American Chibchan-speakers have ancestry from both North and South America, reflecting back-migration from South America and mixture of two widely separated strands of Native ancestry. Second, the Naukan and coastal Chukchi from north-eastern Siberia carry 'First American' DNA. Thus, Eskimo-Aleut speakers migrated back to Asia, bringing Native American genes.
The team's analysis was complicated by the influx into the hemisphere of European and African immigrants since 1492 and the 500 years of genetic mixing that followed. To address this, the authors developed methods that allowed them to focus on the sections of peoples' genomes that were of entirely Native American origin.
"The study of Native American populations is technically very challenging because of the widespread occurrence of European and African mixture in Native American groups," said Professor Ruiz-Linares.
"We developed a method to peel back this mixture to learn about the relationships among Native Americans before Europeans and Africans arrived," Professor Reich said, "allowing us to study the history of many more Native American populations than we could have done otherwise."
The assembly of DNA samples from such a diverse range of populations was only possible through a collaboration of an international team of 64 researchers from the Americas (Argentina, Bolivia, Brazil, Canada, Chile, Colombia, Costa Rica, Guatemala, Mexico, Peru, Russia and the USA), Europe (England, France, Spain and Switzerland) and Russia.
Monday, July 2, 2012
A monumental synagogue building dating to the Late Roman period (ca. 4th-5th centuries C.E.) has been discovered in archaeological excavations at Huqoq in Israel’s Galilee.
The excavations are being conducted by Jodi Magness of the University of North Carolina at Chapel Hill and David Amit and Shua Kisilevitz of the Israel Antiquities Authority, under the sponsorship of UNC, Brigham Young University in Utah, Trinity University in Texas, the University of Oklahoma and the University of Toronto in Canada. Students and staff from UNC and the consortium schools are participating in the dig.
Huqoq is an ancient Jewish village located approximately two to three miles west of Capernaum and Migdal (Magdala). This second season of excavations has revealed portions of a stunning mosaic floor decorating the interior of the synagogue building. The mosaic, which is made of tiny colored stone cubes of the highest quality, includes a scene depicting Samson placing torches between the tails of foxes (as related in the book of Judges 15). In another part of the mosaic, two human (apparently female) faces flank a circular medallion with a Hebrew inscription that refers to rewards for those who perform good deeds.
“This discovery is significant because only a small number of ancient (Late Roman) synagogue buildings are decorated with mosaics showing biblical scenes, and only two others have scenes with Samson (one is at another site just a couple of miles from Huqoq),” said Magness, the Kenan Distinguished Professor in the department of religious studies in UNC’s College of Arts and Sciences. “Our mosaics are also important because of their high artistic quality and the tiny size of the mosaic cubes. This, together with the monumental size of the stones used to construct the synagogue’s walls, suggest a high level of prosperity in this village, as the building clearly was very costly.”
Excavations are scheduled to continue in summer 2013.