A new study of DNA from ancient and modern chickens has shed light on the controversy about the extent of pre-historic Polynesian contact with the Americas.
The study questions recent claims that chickens were first introduced into South America by Polynesians, before the arrival of Spanish chickens in the 15th century following Christopher Columbus.
It is published this week in the Proceedings of the National Academy of Sciences USA (July 28) by an international research group, including scientists from the University of Adelaide’s Australian Centre for Ancient DNA (ACAD).
ACAD Director Professor Alan Cooper says there has been considerable debate about the existence and degree of contact between Polynesians and South Americans, with the presence of the sweet potato throughout the Pacific often used as evidence of early trading contacts.
“Similarly, Polynesians are known to have spread chickens across the Pacific at least as far as Easter Island, but were not thought to have introduced them to South America,” he says
A recent study claimed to have found the first direct evidence of a genetic link between ancient Polynesian and apparently pre-Columbian chickens from archaeological sites in Chile, supporting the idea that there was extensive contact between Polynesia and South America and that chicken and ‘chips’ had been traded in opposite directions.
The current work challenges this conclusion however, by generating DNA data from 41 native Chilean chicken specimens, and comparing these with over 1000 modern domestic chickens from around the world, and the previously published DNA from Polynesian and Chilean chicken bones.
“The results showed that the ancient Polynesian and Chilean chickens possessed a genetic sequence that is the most common in the world today, the so-called ‘KFC’ gene” Professor Cooper says. “This sequence would undoubtedly have been common in the early Spanish chickens, and therefore provides no evidence of Polynesian contact. So while we can say the KFC chicken was popular amongst early Polynesian voyagers, we certainly can’t use it as evidence for trade with South America”.
The researchers did find a highly unusual DNA sequence in the ancient Easter Island chickens, which originate from Indonesia or the Philippines, but this apparently did not get passed on to South America. “This is important because Easter Island is commonly thought of as a major jumping off point for Polynesian contact with South America,” says team member and ACAD PhD student Nicolas Rawlence.
According to project leader Dr Jaime Gongora from Sydney University, many people in South America like to believe they are descendants of Polynesians. “This study does not disprove this idea, but we have found no evidence to support pre-historic contact.”
Thursday, July 31, 2008
Tuesday, July 1, 2008
Tell Edfu in Southern Egypt
A University of Chicago expedition at Tell Edfu in southern Egypt has unearthed a large administration building and silos that provide fresh clues about the emergence of urban life.
The discovery provides new information about a little understood aspect of ancient Egypt—the development of cities in a culture that is largely famous for its monumental architecture.
The archaeological work at Tell Edfu was initiated with the permission of the Supreme Council of Antiquities, headed by Zahi Hawass, under the direction of Nadine Moeller, Assistant Professor at the Oriental Institute, University of Chicago. Work late last year revealed details of seven silos, the largest grain bins found in ancient Egypt as well as an older columned hall that was an administration center.
Long fascinated with temples and monuments such as pyramids, scholars have traditionally spent little time exploring the residential communities of ancient Egypt. Due to intense farming and heavy settlement over the years, much of the record of urban civilization has been lost. So little archaeological evidence remains that some scholars believe Egypt did not have a highly developed urban culture, giving Mesopotamia the distinction of teaching people how to live in cities.
"The traditional view of ancient Egypt has been biased by the fact that most excavation work so far has focused on temples and tombs. The mounds which comprise the remains of Egyptian cities were either ignored, buried under modern towns, or else destroyed by modern agricultural activities. Edfu is one of the very few remaining city mounds that are accessible for scientific study," said Gil Stein, Director of the Oriental Institute.
"The work at Edfu is important and innovative in that it finally allows us to examine ancient Egypt as an urban society, whose cities and towns housed bureaucrats, craft specialists, priests, and farmers. Nadine Moeller's discovery of silos and local administrative buildings shows us how these cities actually functioned as places where the agricultural wealth of the Nile valley was mobilized for the state. Grain as currency provided the sinews of power for the pharoahs," he added.
"Ancient Egyptian administration is mainly known from texts, but the full understanding of the institutions involved and their role within towns and cities has been so far difficult to grasp because of the lack of archaeological evidence with which textual data needs to be combined," Moeller said.
At Tell Edfu, archaeologists have uncovered what amounts to a downtown area. The community, halfway between the modern cities of Aswan and Luxor, was a provincial capital an important regional center. Tell Edfu is also rare, in that almost 3,000 years of Egyptian history are preserved in the stratigraphy of a single mound.
The administrative building and silos were at the heart of the ancient community. Because grain was a form of currency, the silos functioned as a bank and a food source. The silos' size indicates the community was apparently a prosperous urban center.
The grain bins are in a large silo courtyard of the 17th Dynasty (1630-1520 B.C.) and consist of at least seven round, mud-brick silos. With a diameter between 5.5 and 6.5 meters, they are the largest examples discovered within a town center.
The team unearthed an earlier building phase for the hall that predated the silos. In that phase, a mud-brick building with 16 wooden columns stood at the site. The pottery and seal impressions found in the hall date it to the early 13th Dynasty (1773-1650 B.C.). The building layout indicates that it may have been part of the governor's palace, which was typical of provincial towns.
There is no exact parallel for such a columned hall being part of the administrative buildings. Scribes did accounting, opened and sealed containers, and received letters in the column hall. The ostraca, or inscribed pottery shards, list commodities written on them.
The administrative center was used when Egypt's political unity was lost and a small kingdom developed at Thebes (modern Luxor) and controlled most of Upper Egypt.
"During this period, we can see an increase in connections between the provincial elite, such as the family of the governor, to the royal family at Thebes, who were keen on strengthening bonds through marriage, or by awarding important offices to these people," Moeller said.
"It is exactly at this period when Edfu seems to have been very prosperous, which can now be confirmed further by archaeological discoveries such as this silo-court, a symbol for the wealth of the town," she said.
The discovery provides new information about a little understood aspect of ancient Egypt—the development of cities in a culture that is largely famous for its monumental architecture.
The archaeological work at Tell Edfu was initiated with the permission of the Supreme Council of Antiquities, headed by Zahi Hawass, under the direction of Nadine Moeller, Assistant Professor at the Oriental Institute, University of Chicago. Work late last year revealed details of seven silos, the largest grain bins found in ancient Egypt as well as an older columned hall that was an administration center.
Long fascinated with temples and monuments such as pyramids, scholars have traditionally spent little time exploring the residential communities of ancient Egypt. Due to intense farming and heavy settlement over the years, much of the record of urban civilization has been lost. So little archaeological evidence remains that some scholars believe Egypt did not have a highly developed urban culture, giving Mesopotamia the distinction of teaching people how to live in cities.
"The traditional view of ancient Egypt has been biased by the fact that most excavation work so far has focused on temples and tombs. The mounds which comprise the remains of Egyptian cities were either ignored, buried under modern towns, or else destroyed by modern agricultural activities. Edfu is one of the very few remaining city mounds that are accessible for scientific study," said Gil Stein, Director of the Oriental Institute.
"The work at Edfu is important and innovative in that it finally allows us to examine ancient Egypt as an urban society, whose cities and towns housed bureaucrats, craft specialists, priests, and farmers. Nadine Moeller's discovery of silos and local administrative buildings shows us how these cities actually functioned as places where the agricultural wealth of the Nile valley was mobilized for the state. Grain as currency provided the sinews of power for the pharoahs," he added.
"Ancient Egyptian administration is mainly known from texts, but the full understanding of the institutions involved and their role within towns and cities has been so far difficult to grasp because of the lack of archaeological evidence with which textual data needs to be combined," Moeller said.
At Tell Edfu, archaeologists have uncovered what amounts to a downtown area. The community, halfway between the modern cities of Aswan and Luxor, was a provincial capital an important regional center. Tell Edfu is also rare, in that almost 3,000 years of Egyptian history are preserved in the stratigraphy of a single mound.
The administrative building and silos were at the heart of the ancient community. Because grain was a form of currency, the silos functioned as a bank and a food source. The silos' size indicates the community was apparently a prosperous urban center.
The grain bins are in a large silo courtyard of the 17th Dynasty (1630-1520 B.C.) and consist of at least seven round, mud-brick silos. With a diameter between 5.5 and 6.5 meters, they are the largest examples discovered within a town center.
The team unearthed an earlier building phase for the hall that predated the silos. In that phase, a mud-brick building with 16 wooden columns stood at the site. The pottery and seal impressions found in the hall date it to the early 13th Dynasty (1773-1650 B.C.). The building layout indicates that it may have been part of the governor's palace, which was typical of provincial towns.
There is no exact parallel for such a columned hall being part of the administrative buildings. Scribes did accounting, opened and sealed containers, and received letters in the column hall. The ostraca, or inscribed pottery shards, list commodities written on them.
The administrative center was used when Egypt's political unity was lost and a small kingdom developed at Thebes (modern Luxor) and controlled most of Upper Egypt.
"During this period, we can see an increase in connections between the provincial elite, such as the family of the governor, to the royal family at Thebes, who were keen on strengthening bonds through marriage, or by awarding important offices to these people," Moeller said.
"It is exactly at this period when Edfu seems to have been very prosperous, which can now be confirmed further by archaeological discoveries such as this silo-court, a symbol for the wealth of the town," she said.
Monday, June 23, 2008
Britain’s last Neanderthals were sophisticated
An archaeological excavation at a site near Pulborough, West Sussex, has thrown remarkable new light on the life of northern Europe’s last Neanderthals. It provides a snapshot of a thriving, developing population – rather than communities on the verge of extinction.
“The tools we’ve found at the site are technologically advanced and potentially older than tools in Britain belonging to our own species, Homo sapiens,” says Dr Matthew Pope of Archaeology South East based at the UCL Institute of Archaeology. “It’s exciting to think that there’s a real possibility these were left by some of the last Neanderthal hunting groups to occupy northern Europe. The impression they give is of a population in complete command of both landscape and natural raw materials with a flourishing technology - not a people on the edge of extinction.”
The team, led by Dr Pope and funded by English Heritage, is undertaking the first modern, scientific investigation of the site since its original discovery in 1900. During the construction of a monumental house known as ‘Beedings’ some 2,300 perfectly preserved stone tools were removed from fissures encountered in the foundation trenches.
Only recently were the tools recognised for their importance. Research by Roger Jacobi of the Leverhulme-funded Ancient Human Occupation of Britain (AHOB) Project showed conclusively that the Beedings material has strong affinities with other tools from northern Europe dating back to between 35,000 and 42,000 years ago. The collection of tools from Beedings is more diverse and extensive than any other found in the region and therefore offers the best insight into the technologically advanced cultures which occupied Northern Europe before the accepted appearance of our own species.
“Dr Jacobi’s work showed the clear importance of the site,” says Dr Pope. “The exceptional collection of tools appears to represent the sophisticated hunting kit of Neanderthal populations which were only a few millennia from complete disappearance in the region. Unlike earlier, more typical Neanderthal tools these were made with long, straight blades - blades which were then turned into a variety of bone and hide processing implements, as well as lethal spear points.
“There were some questions about the validity of the earlier find, but our excavations have proved beyond doubt that the material discovered here was genuine and originated from fissures within the local sandstone. We also discovered older, more typical Neanderthal tools, deeper in the fissure. Clearly, Neanderthal hunters were drawn to the hill over a long period time, presumably for excellent views of the game-herds grazing on the plains below the ridge.”
The excavations suggest the site may not be unique. Similar sites with comparable fissure systems are thought to exist across south east England. The project now aims to prospect more widely across the region for similar sites.
Barney Sloane, Head of Historic Environment Commissions at English Heritage, said: “Sites such as this are extremely rare and a relatively little considered archaeological resource. Their remains sit at a key watershed in the evolutionary history of northern Europe. The tools at Beedings could equally be the signature of pioneer populations of modern humans, or traces of the last Neanderthal hunting groups to occupy the region. This study offers a rare chance to answer some crucial questions about just how technologically advanced Neanderthals were, and how they compare with our own species.”
“The tools we’ve found at the site are technologically advanced and potentially older than tools in Britain belonging to our own species, Homo sapiens,” says Dr Matthew Pope of Archaeology South East based at the UCL Institute of Archaeology. “It’s exciting to think that there’s a real possibility these were left by some of the last Neanderthal hunting groups to occupy northern Europe. The impression they give is of a population in complete command of both landscape and natural raw materials with a flourishing technology - not a people on the edge of extinction.”
The team, led by Dr Pope and funded by English Heritage, is undertaking the first modern, scientific investigation of the site since its original discovery in 1900. During the construction of a monumental house known as ‘Beedings’ some 2,300 perfectly preserved stone tools were removed from fissures encountered in the foundation trenches.
Only recently were the tools recognised for their importance. Research by Roger Jacobi of the Leverhulme-funded Ancient Human Occupation of Britain (AHOB) Project showed conclusively that the Beedings material has strong affinities with other tools from northern Europe dating back to between 35,000 and 42,000 years ago. The collection of tools from Beedings is more diverse and extensive than any other found in the region and therefore offers the best insight into the technologically advanced cultures which occupied Northern Europe before the accepted appearance of our own species.
“Dr Jacobi’s work showed the clear importance of the site,” says Dr Pope. “The exceptional collection of tools appears to represent the sophisticated hunting kit of Neanderthal populations which were only a few millennia from complete disappearance in the region. Unlike earlier, more typical Neanderthal tools these were made with long, straight blades - blades which were then turned into a variety of bone and hide processing implements, as well as lethal spear points.
“There were some questions about the validity of the earlier find, but our excavations have proved beyond doubt that the material discovered here was genuine and originated from fissures within the local sandstone. We also discovered older, more typical Neanderthal tools, deeper in the fissure. Clearly, Neanderthal hunters were drawn to the hill over a long period time, presumably for excellent views of the game-herds grazing on the plains below the ridge.”
The excavations suggest the site may not be unique. Similar sites with comparable fissure systems are thought to exist across south east England. The project now aims to prospect more widely across the region for similar sites.
Barney Sloane, Head of Historic Environment Commissions at English Heritage, said: “Sites such as this are extremely rare and a relatively little considered archaeological resource. Their remains sit at a key watershed in the evolutionary history of northern Europe. The tools at Beedings could equally be the signature of pioneer populations of modern humans, or traces of the last Neanderthal hunting groups to occupy the region. This study offers a rare chance to answer some crucial questions about just how technologically advanced Neanderthals were, and how they compare with our own species.”
Thursday, May 29, 2008
Rewriting Greenland's immigration history
Thirty-six-year-old Professor Eske Willerslev, University of Copenhagen, and his team of fossil DNA researchers have done it a couple of times before: rewritten world history. Most recently two months ago when he and his team discovered that the ancestors of the North American Indians were the first people to populate America, and that they came to the country more than 1,000 years earlier than originally assumed. And the evidence is, so to speak, quite tangible: DNA samples of fossilised human faeces found in deep caves in southern Oregon.
This time, focus is on Greenland, and the scientific evidence is DNA analyses of hair from the Disco Bay ice fjord area in north-west Greenland, which are well-preserved after 4,000 years in permafrost soil. The team’s discovery makes it necessary to review Greenland’s immigration history. Until now, science regarded it as a possibility that the earliest people in Greenland were direct ancestors of the present-day Greenlandic population.
It now turns out that the original immigrants on the maternal side, which is reflected in the mitochondrial DNA, instead came from a Siberian population whose closest present-day descendants come from the Aleutian Islands on the boundary between the Northern Pacific Ocean and the Bering Sea and the Seriniki Yuit in north-east Siberia. Discovered in more recent times by the Dane Vitus Bering in 1741, the Aleutian Islands today include some 300 islands spanning 1,900 km from Alaska in the USA to the Kamchatka peninsula in Russia.
“They must have crossed the ice from the Aleutian Islands via Alaska and Canada and then on to Greenland. We have always known that the first immigrants came to Greenland approx. 4,500 years ago, because tools from that time have been found. But what we did not know was that they probably came via the Aleutian Islands, which our DNA research now shows. The project was actually close to being shelved. Originally, I was in the most northern part of Greenland with Claus Andreasen from the National Museum of Greenland, Nuuk, looking for DNA traces. It was a total failure. But in another context, I found out that archaeologist Bjarne Grønnow from the National Museum of Denmark, Copenhagen, had made some excavations at the Qeqertasussuk settlement in the northern part of West Greenland in the 1980s. And then, among all the samples taken from the frozen culture layers on the site, I suddenly found a tuft of hair which I analysed together with my colleague Tom Gilbert,” says Eske Willerslev.
‘The forgotten Greenlandic hair’ from the samples was subsequently analysed for so-called mitochondria. They are the genes on the maternal side, a kind of cellular power plant, and they are well-suited for comparative DNA studies of mammals, including humans. The Willerslev team then checked the results of the analysis of the Greenlandic hair against an international DNA database and the database came up with the eastern part of Siberia and the Aleutian Islands, which is populated by a group that has peopled other places in the Arctic area.
Another interesting finding is that there is no connection between this DNA mass and the most recent immigration to Greenland, the Thule culture, the ancestors of modern Greenlandic Inuit.
“Our findings prove that humans moved to other places far earlier than what is normally assumed today. We may only have studied the mitochondria – the female part, but it is the first time ever that someone has succeeded in sequencing the entire mitochondrial genome from an extinct human. Our next project will be to raise funds for recreating what is technically known as the core genome from the tuft of hair, in other words the first full picture of the genetic material of an extinct human. Today, this is technically possible, and it may tell us where the paternal line came from in the earliest immigration to Greenland, and, for example, the eye colour of these early people. The paternal line may very well come from a totally different place,” says Eske Willerslev, who will shortly publish his autobiographical book ‘Fra pelsjæger til professor – en personlig rejse gennem fortidens dna-mysterier’ (From fur hunter to professor – a personal journey through the DNA mysteries of the past).
This time, focus is on Greenland, and the scientific evidence is DNA analyses of hair from the Disco Bay ice fjord area in north-west Greenland, which are well-preserved after 4,000 years in permafrost soil. The team’s discovery makes it necessary to review Greenland’s immigration history. Until now, science regarded it as a possibility that the earliest people in Greenland were direct ancestors of the present-day Greenlandic population.
It now turns out that the original immigrants on the maternal side, which is reflected in the mitochondrial DNA, instead came from a Siberian population whose closest present-day descendants come from the Aleutian Islands on the boundary between the Northern Pacific Ocean and the Bering Sea and the Seriniki Yuit in north-east Siberia. Discovered in more recent times by the Dane Vitus Bering in 1741, the Aleutian Islands today include some 300 islands spanning 1,900 km from Alaska in the USA to the Kamchatka peninsula in Russia.
“They must have crossed the ice from the Aleutian Islands via Alaska and Canada and then on to Greenland. We have always known that the first immigrants came to Greenland approx. 4,500 years ago, because tools from that time have been found. But what we did not know was that they probably came via the Aleutian Islands, which our DNA research now shows. The project was actually close to being shelved. Originally, I was in the most northern part of Greenland with Claus Andreasen from the National Museum of Greenland, Nuuk, looking for DNA traces. It was a total failure. But in another context, I found out that archaeologist Bjarne Grønnow from the National Museum of Denmark, Copenhagen, had made some excavations at the Qeqertasussuk settlement in the northern part of West Greenland in the 1980s. And then, among all the samples taken from the frozen culture layers on the site, I suddenly found a tuft of hair which I analysed together with my colleague Tom Gilbert,” says Eske Willerslev.
‘The forgotten Greenlandic hair’ from the samples was subsequently analysed for so-called mitochondria. They are the genes on the maternal side, a kind of cellular power plant, and they are well-suited for comparative DNA studies of mammals, including humans. The Willerslev team then checked the results of the analysis of the Greenlandic hair against an international DNA database and the database came up with the eastern part of Siberia and the Aleutian Islands, which is populated by a group that has peopled other places in the Arctic area.
Another interesting finding is that there is no connection between this DNA mass and the most recent immigration to Greenland, the Thule culture, the ancestors of modern Greenlandic Inuit.
“Our findings prove that humans moved to other places far earlier than what is normally assumed today. We may only have studied the mitochondria – the female part, but it is the first time ever that someone has succeeded in sequencing the entire mitochondrial genome from an extinct human. Our next project will be to raise funds for recreating what is technically known as the core genome from the tuft of hair, in other words the first full picture of the genetic material of an extinct human. Today, this is technically possible, and it may tell us where the paternal line came from in the earliest immigration to Greenland, and, for example, the eye colour of these early people. The paternal line may very well come from a totally different place,” says Eske Willerslev, who will shortly publish his autobiographical book ‘Fra pelsjæger til professor – en personlig rejse gennem fortidens dna-mysterier’ (From fur hunter to professor – a personal journey through the DNA mysteries of the past).
Thursday, May 8, 2008
Genetics Confirm Oral Traditions of Druze in Israel
DNA analysis of residents of Druze villages in Israel suggests these ancient religious communities offer a genetic snapshot of the Near East as it was several thousands of years ago.
The Druze harbor a remarkable diversity of mitochondrial DNA types or lineages that appear to have separated from each other many thousands of years ago, according to a new study by multinational team, led by researchers at the Technion-Israel Institute of Technology Rappaport School of Medicine.
But instead of dispersing throughout the world after their separation, the full range of lineages can still be found within the small, tightly knit Druze population.
Technion researcher Karl Skorecki noted that the findings are consistent with Druze oral tradition suggesting the adherents came from diverse ancestral lineages "stretching back tens of thousands of years." The Druze represent a "genetic sanctuary" or "living relic" that provides a glimpse of the genetic diversity of the Near East in antiquity, the researchers write in the May 7th issue of the journal PLoS ONE.
But there is a modern twist to their story: the diversity of Druze mitochondrial DNA, which is the part of the genome that is passed on strictly through the maternal line, offers a unique opportunity for researchers to study whether people in different mitochondrial DNA lineages are predisposed to different kinds of diseases.
Skorecki points to metabolic syndrome, the combination of insulin resistance, high cholesterol, abdominal obesity and other factors, as one such disease. Mitochondria are the energy factories within cells, so one might expect that differences in mitochondrial DNA might be linked to different predispositions to energy-related diseases such as metabolic syndrome, he explained.
With the Druze, "you can look at 150 kinds of mitochondrial DNA within one group with a similar environment, and be able to see the specific contribution of these variations" to disease, Skorecki said.
Dan Mishmar, a genetics researcher at Ben-Gurion University who was not involved with the study, said there is another "great advantage" to studying the link between disease and mitochondrial DNA variation in a group like the Druze. Although the Druze have great variety in their mitochondrial genome, the rest of their genome inherited from both paternal and maternal lines has grown less diverse as a result of thousands of years of intermarriage.
That means that researchers searching for genetic mutations linked to disease would have an easier time discerning whether these mutations are limited to the mitochondrial genome, which could help researchers design specific, targeted therapies, Mishmar explained.
The findings also guide the approach to screen for genetic disease among the Druze. Instead of scanning for disease-linked genes associated with an entire population--as is the case with Ashkenazi Jews, for example-it may make sense to screen within smaller groups. "Since they are comprised of so many distinct lineages, genetic disease may vary from clan to clan and village to village," Skorecki explained.
The researchers, including Druze co-authors Fuad Basis of the Rambam Medical Center and former Technion student Yarin Hadid, took genetic samples from 311 Druze households in 20 villages in Israel. They soon discovered an unusually high frequency of a mitochondrial DNA haplogroup-a distinct collection of genetic markers - called haplogroup X - among the Druze. Haplogroup X is found at low frequencies throughout the world, and is not confined to a specific geographical region as are most other mitochondrial DNA haplogroups.
Even more unusual, the Druze villages contained a striking range of variations on the X haplogroup. Together, the high frequency and high diversity of the X haplogroup "suggest that this population provides a glimpse into the past genetic landscape of the Near East, at a time when the X haplogroup was more prevalent," the researchers note.
How did the Druze become a genetic sanctuary in the Near East? The religious minority has lived for centuries in remote, mountainous regions, and unlike other monotheistic religions, the group has not sought converts since shortly after the "Dawa" or "revelation" of the religion in 1017 C.E. These factors, along with other cultural and political practices, may have kept the Druze a people apart for thousands of years, according to Skorecki and colleagues.
Skorecki is best-known for his 1997 discovery of genetic evidence indicating that the majority of modern-day Jewish priests (Kohanim) are descendants of a single common male ancestor, consistent with the Biblical high priest, Aaron. He also led an international team of researchers who, in 2006, found that some 3.5 million or 40 percent of Ashkenazi Jews are descended from just four "founding mothers," who lived in Europe 1,000 years ago.
The Druze harbor a remarkable diversity of mitochondrial DNA types or lineages that appear to have separated from each other many thousands of years ago, according to a new study by multinational team, led by researchers at the Technion-Israel Institute of Technology Rappaport School of Medicine.
But instead of dispersing throughout the world after their separation, the full range of lineages can still be found within the small, tightly knit Druze population.
Technion researcher Karl Skorecki noted that the findings are consistent with Druze oral tradition suggesting the adherents came from diverse ancestral lineages "stretching back tens of thousands of years." The Druze represent a "genetic sanctuary" or "living relic" that provides a glimpse of the genetic diversity of the Near East in antiquity, the researchers write in the May 7th issue of the journal PLoS ONE.
But there is a modern twist to their story: the diversity of Druze mitochondrial DNA, which is the part of the genome that is passed on strictly through the maternal line, offers a unique opportunity for researchers to study whether people in different mitochondrial DNA lineages are predisposed to different kinds of diseases.
Skorecki points to metabolic syndrome, the combination of insulin resistance, high cholesterol, abdominal obesity and other factors, as one such disease. Mitochondria are the energy factories within cells, so one might expect that differences in mitochondrial DNA might be linked to different predispositions to energy-related diseases such as metabolic syndrome, he explained.
With the Druze, "you can look at 150 kinds of mitochondrial DNA within one group with a similar environment, and be able to see the specific contribution of these variations" to disease, Skorecki said.
Dan Mishmar, a genetics researcher at Ben-Gurion University who was not involved with the study, said there is another "great advantage" to studying the link between disease and mitochondrial DNA variation in a group like the Druze. Although the Druze have great variety in their mitochondrial genome, the rest of their genome inherited from both paternal and maternal lines has grown less diverse as a result of thousands of years of intermarriage.
That means that researchers searching for genetic mutations linked to disease would have an easier time discerning whether these mutations are limited to the mitochondrial genome, which could help researchers design specific, targeted therapies, Mishmar explained.
The findings also guide the approach to screen for genetic disease among the Druze. Instead of scanning for disease-linked genes associated with an entire population--as is the case with Ashkenazi Jews, for example-it may make sense to screen within smaller groups. "Since they are comprised of so many distinct lineages, genetic disease may vary from clan to clan and village to village," Skorecki explained.
The researchers, including Druze co-authors Fuad Basis of the Rambam Medical Center and former Technion student Yarin Hadid, took genetic samples from 311 Druze households in 20 villages in Israel. They soon discovered an unusually high frequency of a mitochondrial DNA haplogroup-a distinct collection of genetic markers - called haplogroup X - among the Druze. Haplogroup X is found at low frequencies throughout the world, and is not confined to a specific geographical region as are most other mitochondrial DNA haplogroups.
Even more unusual, the Druze villages contained a striking range of variations on the X haplogroup. Together, the high frequency and high diversity of the X haplogroup "suggest that this population provides a glimpse into the past genetic landscape of the Near East, at a time when the X haplogroup was more prevalent," the researchers note.
How did the Druze become a genetic sanctuary in the Near East? The religious minority has lived for centuries in remote, mountainous regions, and unlike other monotheistic religions, the group has not sought converts since shortly after the "Dawa" or "revelation" of the religion in 1017 C.E. These factors, along with other cultural and political practices, may have kept the Druze a people apart for thousands of years, according to Skorecki and colleagues.
Skorecki is best-known for his 1997 discovery of genetic evidence indicating that the majority of modern-day Jewish priests (Kohanim) are descendants of a single common male ancestor, consistent with the Biblical high priest, Aaron. He also led an international team of researchers who, in 2006, found that some 3.5 million or 40 percent of Ashkenazi Jews are descended from just four "founding mothers," who lived in Europe 1,000 years ago.
Earliest known human settlement in the Americas
New evidence from earliest known human settlement in the Americas
Provides support for coastal migration theories
New evidence from the Monte Verde archaeological site in southern Chile confirms its status as the earliest known human settlement in the Americas and provides additional support for the theory that one early migration route followed the Pacific Coast more than 14,000 years ago.
The study was conducted by a team of anthropologists, geologists and botanists headed by Vanderbilt University’s Distinguished Professor of Anthropology Tom Dillehay and was reported in the May 9 issue of the journal Science.
The paper, which includes the first new data reported from the site in 10 years, includes the identification of nine species of seaweed and marine algae recovered from hearths and other areas in the ancient settlement. The seaweed samples were directly dated between 14,220 to 13,980 years ago, confirming that the upper layer of the site, labeled Monte Verde II, was occupied more than 1,000 years earlier than any other reliably dated human settlements in the Americas.
The Monte Verde site was discovered in 1976. It is located in a peat bog about 500 miles south of Santiago and has revealed well-preserved ruins of a small settlement of 20 to 30 people living in a dozen huts along a small creek. A wide variety of food has been found at the site, including extinct species of llama and an elephant-like animal called a gomphothere, shellfish, vegetables and nuts.
In 1979, when Dillehay and his colleagues first reported that the radiocarbon dating of the bones and charcoal found at Monte Verde returned dates of more than 14,000 years before the present, it stirred up a major controversy because the early dates appeared to conflict with other archaeological evidence of the settlement of North America.
Since at least 1900, the prevailing theory had been that human colonization began at the end of the last Ice Age about 13,000 years ago, when groups of big game hunters, called the Clovis culture, followed herds from Siberia to Alaska over a land bridge across the Bering Strait and then gradually spread southward. None of the Clovis artifacts were dated earlier than 13,000 years ago. So having a substantially older human settlement in southern Chile was difficult to reconcile with this view.
It wasn’t until 1997 that the controversy was resolved by a prominent group of archaeologists who reviewed the evidence, visited the Monte Verde site and unanimously approved the dating.
Most scholars now believe that people first entered the new world through the Bering land bridge more than 16,000 years ago. After entering Alaska, it is not known whether they colonized the hemisphere by moving down the Pacific coast, by inland routes or both. The general view is that the early immigrants would have spread down the coast much faster than they could move inland because they could exploit familiar coastal resources more readily and get much of their food from the sea. However, evidence to support the coastal migration theory has been particularly hard to find because sea levels at the time were about 200 feet lower than today: As the sea level rose, it would have covered most of the early coastal settlements.
According to Dillehay, the new Monte Verde findings provide additional support for the coastal migration theory but, at the same time, raise the possibility that the process may have been considerably slower than currently envisioned.
At the time it was inhabited, Monte Verde was situated on a small tributary of a large river. It was about 400 feet above sea level and located more than 50 miles from the coast and about 10 miles from a large marine bay. Despite its inland location, the researchers identified a total of nine different species of seaweed and algae in the material collected at the site — material that the Monte Verdeans must have brought from the coast and the bay. The researchers have also found a variety of other beach or coastal resources, including flat beach pebbles, water plants from brackish estuaries and bitumen.
“Finding seaweed wasn’t a surprise, but finding five new species in the abundance that we found them was a surprise,” said Dillehay. “There are other coastal resources at the site. The Monte Verdeans were really like beachcombers: The number and frequency of these items suggests very frequent contact with the coast, as if they had a tradition of exploiting coastal resources.”
In addition, the scientists have found a number of inland resources, such as the gomphothere meat, in the ancient village. This suggests that the group was moving back and forth between different ecological zones, a process called transhumance.
“It takes time to adapt to these inland resources and then come back out to the coast. The other coastal sites that we have found also show inland contacts. If all the early American groups were following a similar pattern of moving back and forth between inland and coastal areas, then the peopling of the Americas may not have been the blitzkrieg movement to the south that people have presumed, but a much slower and more deliberate process,” Dillehay observed.
Provides support for coastal migration theories
New evidence from the Monte Verde archaeological site in southern Chile confirms its status as the earliest known human settlement in the Americas and provides additional support for the theory that one early migration route followed the Pacific Coast more than 14,000 years ago.
The study was conducted by a team of anthropologists, geologists and botanists headed by Vanderbilt University’s Distinguished Professor of Anthropology Tom Dillehay and was reported in the May 9 issue of the journal Science.
The paper, which includes the first new data reported from the site in 10 years, includes the identification of nine species of seaweed and marine algae recovered from hearths and other areas in the ancient settlement. The seaweed samples were directly dated between 14,220 to 13,980 years ago, confirming that the upper layer of the site, labeled Monte Verde II, was occupied more than 1,000 years earlier than any other reliably dated human settlements in the Americas.
The Monte Verde site was discovered in 1976. It is located in a peat bog about 500 miles south of Santiago and has revealed well-preserved ruins of a small settlement of 20 to 30 people living in a dozen huts along a small creek. A wide variety of food has been found at the site, including extinct species of llama and an elephant-like animal called a gomphothere, shellfish, vegetables and nuts.
In 1979, when Dillehay and his colleagues first reported that the radiocarbon dating of the bones and charcoal found at Monte Verde returned dates of more than 14,000 years before the present, it stirred up a major controversy because the early dates appeared to conflict with other archaeological evidence of the settlement of North America.
Since at least 1900, the prevailing theory had been that human colonization began at the end of the last Ice Age about 13,000 years ago, when groups of big game hunters, called the Clovis culture, followed herds from Siberia to Alaska over a land bridge across the Bering Strait and then gradually spread southward. None of the Clovis artifacts were dated earlier than 13,000 years ago. So having a substantially older human settlement in southern Chile was difficult to reconcile with this view.
It wasn’t until 1997 that the controversy was resolved by a prominent group of archaeologists who reviewed the evidence, visited the Monte Verde site and unanimously approved the dating.
Most scholars now believe that people first entered the new world through the Bering land bridge more than 16,000 years ago. After entering Alaska, it is not known whether they colonized the hemisphere by moving down the Pacific coast, by inland routes or both. The general view is that the early immigrants would have spread down the coast much faster than they could move inland because they could exploit familiar coastal resources more readily and get much of their food from the sea. However, evidence to support the coastal migration theory has been particularly hard to find because sea levels at the time were about 200 feet lower than today: As the sea level rose, it would have covered most of the early coastal settlements.
According to Dillehay, the new Monte Verde findings provide additional support for the coastal migration theory but, at the same time, raise the possibility that the process may have been considerably slower than currently envisioned.
At the time it was inhabited, Monte Verde was situated on a small tributary of a large river. It was about 400 feet above sea level and located more than 50 miles from the coast and about 10 miles from a large marine bay. Despite its inland location, the researchers identified a total of nine different species of seaweed and algae in the material collected at the site — material that the Monte Verdeans must have brought from the coast and the bay. The researchers have also found a variety of other beach or coastal resources, including flat beach pebbles, water plants from brackish estuaries and bitumen.
“Finding seaweed wasn’t a surprise, but finding five new species in the abundance that we found them was a surprise,” said Dillehay. “There are other coastal resources at the site. The Monte Verdeans were really like beachcombers: The number and frequency of these items suggests very frequent contact with the coast, as if they had a tradition of exploiting coastal resources.”
In addition, the scientists have found a number of inland resources, such as the gomphothere meat, in the ancient village. This suggests that the group was moving back and forth between different ecological zones, a process called transhumance.
“It takes time to adapt to these inland resources and then come back out to the coast. The other coastal sites that we have found also show inland contacts. If all the early American groups were following a similar pattern of moving back and forth between inland and coastal areas, then the peopling of the Americas may not have been the blitzkrieg movement to the south that people have presumed, but a much slower and more deliberate process,” Dillehay observed.
Wednesday, April 30, 2008
You Are What You Eat? Maybe Not for Ancient Man
Careful analysis of microscopic abrasions on the teeth of early human "cousins" by resesarchers at Johns Hopkins, University of Arkansas, Cambridge University and Stony Brook University show that although equipped with thick enamel, large jaws and powerful chewing muscles, this ancient species may not have eaten the nuts, seeds or roots their anatomy suggests. Instead, the tooth wear suggests a more general diet, as reported in next week's Public Library of Science One.
"For so many years we've operated under the assumption that the shape of something's teeth, jaws and skull tells us what they habitually ate," says Mark Teaford, Ph.D., a professor of anatomy at Hopkins' Center for Functional Anatomy and Evolution. "But it seems like we had the wrong idea - just because they're capable of eating hard foods doesn't mean that they did - it really makes us rethink some of our basic assumptions."
Using high-powered microscopy to scan tooth surfaces and computer programs that measure imperfections on the surfaces of teeth, the researchers analyzed tooth surfaces from Paranthropus boisei from eastern Africa. According to most researchers, P. boisei's jaw and tooth structure was so specialized and extreme it must have had a very specialized diet. In fact, its anatomy gave it the nickname "Nutcracker Man."
Measuring the microwear from permanent molars of P. boisei from Ethiopia, Kenya and Tanzania dating from 2.27 million years ago to about 1.4 million years ago, the team compared their results with microwear from living primates and other fossils. They found that P. boisei teeth had very little pitting indicative of eating hard foods.
"It seems that while they were perhaps capable of eating harder foods, they generally didn't," says Teaford. "We see similar situations in modern primates, who often like soft fruit. But they can't find that all the time, so occasionally they'll eat harder or tougher foods if they have to."
"Looking at P. boisei you think 'wow, it's a chewing machine,' but that's really an oversimplification." "It may not have been so specialized," he adds.
"For so many years we've operated under the assumption that the shape of something's teeth, jaws and skull tells us what they habitually ate," says Mark Teaford, Ph.D., a professor of anatomy at Hopkins' Center for Functional Anatomy and Evolution. "But it seems like we had the wrong idea - just because they're capable of eating hard foods doesn't mean that they did - it really makes us rethink some of our basic assumptions."
Using high-powered microscopy to scan tooth surfaces and computer programs that measure imperfections on the surfaces of teeth, the researchers analyzed tooth surfaces from Paranthropus boisei from eastern Africa. According to most researchers, P. boisei's jaw and tooth structure was so specialized and extreme it must have had a very specialized diet. In fact, its anatomy gave it the nickname "Nutcracker Man."
Measuring the microwear from permanent molars of P. boisei from Ethiopia, Kenya and Tanzania dating from 2.27 million years ago to about 1.4 million years ago, the team compared their results with microwear from living primates and other fossils. They found that P. boisei teeth had very little pitting indicative of eating hard foods.
"It seems that while they were perhaps capable of eating harder foods, they generally didn't," says Teaford. "We see similar situations in modern primates, who often like soft fruit. But they can't find that all the time, so occasionally they'll eat harder or tougher foods if they have to."
"Looking at P. boisei you think 'wow, it's a chewing machine,' but that's really an oversimplification." "It may not have been so specialized," he adds.
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