Monday, February 27, 2017

38,000-year-old engravings confirm ancient origins of pointillist technique used by Seurat, Van Gogh



Newly discovered limestone slab from Abri Cellier with pointillist mammoth in profile view formed my dozens of individual punctuations and re-shaping of the natural edge of the block to conform to the animals head and back line.
CREDIT
Photo and drawing by R. Bourrillon.
A newly discovered trove of 16 engraved and otherwise modified limestone blocks, created 38,000 years ago, confirms the ancient origins of the pointillist techniques later adopted by 19th and 20th century artists such as Georges Seurat, Vincent Van Gogh, Camille Pissarro, and Roy Lichtenstein.

"We're quite familiar with the techniques of these modern artists," observes New York University anthropologist Randall White, who led the excavation in France's Vézère Valley. "But now we can confirm this form of image-making was already being practiced by Europe's earliest human culture, the Aurignacian."

Pointillism, a painting technique in which small dots are used to create the illusion of a larger image, was developed in the 1880s. However, archaeologists have now found evidence of this technique thousands of years earlier -- dating back more than 35,000 years.

The findings appear in the journal Quaternary International.

Major discoveries by White and his colleagues--which include images of mammoths and horses--confirm that a form of pointillism was used by the Aurignacian, the earliest modern human culture in Europe. These add weight to previous isolated discoveries, such as a rhinoceros, from the Grotte Chauvet in France, formed by the application of dozens of dots, first painted on the palm of the hand, and then transferred to the cave wall.

Earlier this year, White's team reported the uncovering of a 38,000-year-old pointillist image of an aurochs or wild cow--a finding that marks some of the earliest known graphic imagery found in Western Eurasia and offers insights into the nature of modern humans during this period. Now, in short order they have found another pointillist image--this time of a woolly mammoth--in a rock shelter of the same period known as Abri Cellier located near the previous find-site of Abri Blanchard.

Abri Cellier has long been on archeologists' short-list of major art-bearing sites attributed to the European Aurignacian. Excavations in 1927 yielded 15 engraved and/or pierced limestone blocks that have served as a key point of reference for the study of Aurignacian art in the region.

In 2014, White and his colleagues returned to Cellier, seeking intact deposits that would allow a better understanding of the archaeological sequence at the site and its relationship to other Aurignacian sites. They had their fingers crossed that the new excavation might yield new engraved images in context, but nothing prepared them for the discovery of the 16 stone blocks detailed in the Quaternary International article. One of these, broken in half prehistorically, was found in place with a radiocarbon date of 38,000 years ago.

Remarkably, the remaining 15 blocks, including the pointillist mammoth, one of three mammoth figures recognized during the new work at Cellier, had been left on-site by the 1927 excavators. As many of the engraved traces are rudimentary and thus difficult to interpret, the original excavators set them aside just in case they might have something inscribed on them. The new article presents evidence that the 38,000 year date for the newly excavated engraving also applies to the new trove and to the other blocks found in 1927 and now housed in the French National Prehistory Museum.



Study shows ancient humans arrived in South America in multiple waves



Analysis of ancient human skulls found in southeastern Brazil are providing new insights into the complex narrative of human migration from our origins in sub-Saharan Africa to the peopling of the Americas tens of thousands of years later.

The many differences in cranial morphology, the study of skull shape, seen in Paleoamerican remains found in the Lagoa Santa region of Brazil suggest a model of human history that included multiple waves of population dispersals from Asia, across the Bering Strait, down the North American coast and into South America.

The findings published Wednesday (Feb. 22, 2017) in the journal Science Advances suggest that Paleoamericans share a last common ancestor with modern native South Americans outside, rather than inside, the Americas and underscore the importance of looking at both genetic and morphological evidence, each revealing different aspects of the human story, to help unravel our species' history.

"When you look at contemporary genomic data, the suggestion, particularly for South America, was for one wave of migration and that indigenous South American people are all descendants of that wave," says Noreen von Cramon-Taubadel, an associate professor of anthropology at the University at Buffalo and the paper's lead author. "But our data is suggesting that there were at least two, if not more, waves of people entering South America."

How people settled the Americas is a debate that has continued for years in the scientific community. It's now clear that the first human entry into the Americas began at least 15,000 years ago and dispersed quickly into South America following a coastal Pacific route.

The conundrum of conflicting data between morphology and genetics is among the issues fueling the debate of how people first entered the New World, but von Cramon-Taubadel's conclusions are similar to previous morphological research while also relying on a pioneering method to reach those conclusions.

"We've adopted and modified the method from ecology, but to my knowledge this method has never been used in an anthropological setting before," she says.

In the past, researchers have looked mainly at the overall similarities between the morphology of prehistoric skeletons from the Americas compared with the morphology of living people. Models of dispersal, each with a different number of waves that attempt to match existing data, have also been used.

But von Cramon-Taubadel's current research with Mark Hubbe, an associate professor in the Department of Anthropology at Ohio State University, and University of Tübingen researcher André Strauss, doesn't make any previous assumptions about dispersals. It looks at an existing population as descendants of many possible branches of a theoretical tree of relatedness and then uses statistics to determine where in the tree their sample best fits.

This method has the advantage of not needing pre-determined models of dispersal but rather considers all possible patterns of relatedness.

All living people, von Cramon-Taubadel explains, have a common ancestor, but not all fossils necessarily contribute to the ancestry of living people. Some populations of modern humans did not survive or made only a marginal contribution to living people. So fossils of these extinct humans provide few clues about the ancestry of living people.

"There are other fossils, particularly in the Americas and Eurasia where at the moment we are not 100 percent sure how they fit into the human picture," von Cramon-Taubadel says. "We could use this method to elucidate where they sit and to what extent those populations actually play a role in the modern ancestry of people in those areas."

Puzzle of the Maya pendant


To say that UC San Diego archaeologist Geoffrey Braswell was surprised to discover a precious jewel in Nim Li Punit in southern Belize is something of an understatement.



The jade once belonging to an ancient Maya king is inscribed with 30 hieroglyphs. It was used during important religious ceremonies.
CREDIT
Courtesy G. Braswell/UC San Diego

"It was like finding the Hope Diamond in Peoria instead of New York," said Braswell, who led the dig that uncovered a large piece of carved jade once belonging to an ancient Maya king. "We would expect something like it in one of the big cities of the Maya world. Instead, here it was, far from the center," he said.

The jewel -- a jade pendant worn on a king's chest during key religious ceremonies -- was first unearthed in 2015. It is now housed at the Central Bank of Belize, along with other national treasures. Braswell recently published a paper in the Cambridge University journal Ancient Mesoamerica detailing the jewel's significance. A second paper, in the Journal of Field Archaeology, describes the excavations.

The pendant is remarkable for being the second largest Maya jade found in Belize to date, said Braswell, a professor in the Department of Anthropology at UC San Diego. The pendant measures 7.4 inches wide, 4.1 inches high and just 0.3 inches thick. Sawing it into this thin, flat form with string, fat and jade dust would have been a technical feat. But what makes the pendant even more remarkable, Braswell said, is that it's the only one known to be inscribed with a historical text. Carved into the pendant's back are 30 hieroglyphs about its first owner.

"It literally speaks to us," Braswell said. "The story it tells is a short but important one." He believes it may even change what we know about the Maya.

Also important: The pendant was "not torn out of history by looters," said Braswell. "To find it on a legal expedition, in context, gives us information about the site and the jewel that we couldn't have otherwise had or maybe even imagined."

Where the jewel was found

Nim Li Punit is a small site in the Toledo District of Belize. It sits on a ridge in the Maya Mountains, near the contemporary village of Indian Creek. Eight different types of parrot fly overhead. It rains nine months of the year.

On the southeastern edge of the ancient Maya zone (more than 250 miles south of Chichen Itza in Mexico, where similar but smaller breast pieces have been found), Nim Li Punit is estimated to have been inhabited between A.D. 150 and 850. The site's name means "big hat." It was dubbed that, after its rediscovery in 1976, for the elaborate headdress sported by one of its stone figures. Its ancient name might be Wakam or Kawam, but this is not certain.

Braswell, UC San Diego graduate students Maya Azarova and Mario Borrero, along with a crew of local people, were excavating a palace built around the year 400 when they found a collapsed, but intact, tomb. Inside the tomb, which dates to about A.D. 800, were 25 pottery vessels, a large stone that had been flaked into the shape of a deity and the precious jade pectoral. Except for a couple of teeth, there were no human remains.

What was it doing there?

The pendant is in the shape of a T. Its front is carved with a T also. This is the Mayan glyph "ik'," which stands for "wind and breath." It was buried, Braswell said, in a curious, T-shaped platform. And one of the pots discovered with it, a vessel with a beaked face, probably depicts a Maya god of wind.

Wind was seen as vital by the Maya. It brought annual monsoon rains that made the crops grow. And Maya kings -- as divine rulers responsible for the weather -- performed rituals according to their sacred calendar, burning and scattering incense to bring on the wind and life-giving rains. According to the inscription on its back, Braswell said, the pendant was first used in A.D. 672 in just such a ritual.

Two relief sculptures on large rock slabs at Nim Li Punit also corroborate that use. In both sculptures, a king is shown wearing the T-shaped pendant while scattering incense, in A.D. 721 and 731, some 50 and 60 years after the pendant was first worn.

By the year 800, the pendant was buried, not with its human owner, it seems, but just with other objects. Why? The pendant wasn't a bauble, Braswell said, "it had immense power and magic." Could it have been buried as a dedication to the wind god? That's Braswell's educated hunch.

Maya kingdoms were collapsing throughout Belize and Guatemala around A.D. 800, Braswell said. Population levels plummeted. Within a generation of the construction of the tomb, Nim Li Punit itself was abandoned.

"A recent theory is that climate change caused droughts that led to the widespread failure of agriculture and the collapse of Maya civilization," Braswell said. "The dedication of this tomb at that time of crisis to the wind god who brings the annual rains lends support to this theory, and should remind us all about the danger of climate change."

Still and again: What was it doing there?

The inscription on the back of the pendant is perhaps the most intriguing thing about it, Braswell said. The text is still being analyzed by Braswell's coauthor on the Ancient Mesoamerica paper, Christian Prager of the University of Bonn. And Mayan script itself is not yet fully deciphered or agreed upon.

But Prager and Braswell's interpretation of the text so far is this: The jewel was made for the king Janaab' Ohl K'inich. In addition to noting the pendant's first use in A.D. 672 for an incense-scattering ceremony, the hieroglyphs describe the king's parentage. His mother, the text implies, was from Cahal Pech, a distant site in western Belize. The king's father died before aged 20 and may have come from somewhere in Guatemala.

It also describes the accession rites of the king in A.D. 647, Braswell said, and ends with a passage that possibly links the king to the powerful and immense Maya city of Caracol, located in modern-day Belize.

"It tells a political story far from Nim Li Punit," Braswell said. He notes that Cahal Pech, the mother's birthplace, for example, is 60 miles away. That's a five-hour bus ride today, and back then would have been many days' walk -- through rainforest and across mountains. How did the pendant come to this outpost?

While it's possible it had been stolen from an important place and whisked away to the provinces, Braswell doesn't think so. He believes the pendant is telling us about the arrival of royalty at Nim Li Punit, the founding of a new dynasty. The writing on the pendant is not particularly old by Maya standards, but it's the oldest found at Nim Li Punit so far, Braswell said. It's also only after the pendant's arrival that other hieroglyphs and images of royalty begin to show up on the site's stelae, or sculptured stone slabs.

It could be that king Janaab' Ohl K'inich himself moved to Nim Li Punit, Braswell said. Or it could be that a great Maya state was trying to ally with the provinces, expand its power or curry favor by presenting a local king with the jewel. Either way, Braswell believes, the writing on the pendant indicates ties that had been previously unknown.

"We didn't think we'd find royal, political connections to the north and the west of Nim Li Punit," said Braswell, who has been excavating in Belize since 2001 and at Nim Li Punit since 2010. "We thought if there were any at all that they'd be to the south and east."

Even if you ignore the writing and its apparent royal provenance, the jade stone itself is from the mountains of Guatemala, southwest of Belize. There are few earlier indications of trade in that direction either, Braswell said.

We may never know exactly why the pendant came to Nim Li Punit or why it was buried as it was, but Braswell's project to understand the site continues. He plans to return in the spring of 2017. This time, he also wants to see if he might discover a tie to the Caribbean Sea. After all, that's a mere 12 miles downriver, a four-hour trip by canoe.

1,800 Year Old Hebrew Inscriptions were Exposed on a Column Capital in Peqiin Village




Margalit Zinati of Peqi?in village, resting on the ancient stone. Photo: Ritvo, courtesy of Beit Zinati


An 1,800 year old limestone capital dating to the Roman period that is engraved with two Hebrew inscriptions was discovered during the course of restoration and conservation work being carried out in the ancient synagogue and neighboring Beit Zinati visitor center at Peqiin, in the Western Galilee. The work is being conducted by the Council for Conservation of Heritage Sites in Israel as part of a heritage project by the Ministry of Jerusalem Affairs and Heritage. The stone was found upside down in the building’s courtyard, and upon discovery of the inscriptions archaeologists of the Israel Antiquities Authority arrived at the site in order to examine the special find. A preliminary analysis of the engraving suggests that these are dedicatory inscriptions honoring donors to the synagogue.

According to Yoav Lerer, the IAA inspector in the Western Galilee, “The Talmudic and Midrashic sources tell of the Galilean sages that lived in Peqiin, including Rabbi Shimon Bar Yochai, who hid from the Romans in a cave. However, there are those who disagree with the identification of the location of Peqi?in. I believe that these inscriptions will add an important tier to our knowledge about the Jewish settlement in the village of Peqiiin during the Roman and Byzantine periods”.

In the past year rehabilitation and conservation work was carried out in Peqiin’s ancient synagogue and nearby Beit Zinati in order to upgrade the visitor center located there. The visitor center will tell the two thousand year long history of the Jews in the village, and the unique story of the Zinati family – the village’s oldest Jewish family. Until today Margalit Zinati, the last member of the Jewish Zinati family to "keep the flame alive", resides in the house next door to the synagogue.

Ze’ev Elkin, the Minister of Jerusalem Affairs and Heritage, said "Peqiin is one of the most significant sites in the Galilee, and is a place where there has always been a Jewish presence. It is a great honor for me that during my tenure in office such an important discovery has been made that tells this 2,000 year old story of the Land of Israel”.

Uriel Rosenboym, director of Beit Zinati says with great excitement “This is a historical discovery of unparalleled importance that confirms what the late President Yitzhak Ben Zvi maintained in the early twentieth century about the Jewish settlement at Peqiin. No one can argue with the written artifact. There was an ancient synagogue here and the synagogue was built in its current form in recent centuries. We thank the Ministry of Jerusalem Affairs and Heritage, which aims to preserve the heritage of Peqiin’s Jews. We are pleased to open the new museum with a historic message about this ancient community. Although the stone itself was taken to be studied by the Israel Antiquities Authority, this unique story of the keepers of the flame in Peqiin is revealed in the renewed museum”.


Discovery of Rare Bronze Age Weapon Hoard



GUARD Archaeologists have recently recovered a very rare and internationally significant hoard of metalwork that is a major addition to Scottish Late Bronze Age archaeology.

A bronze spearhead decorated with gold was found alongside a bronze sword, pin and scabbard fittings in a pit close to a Bronze Age settlement excavated by a team of GUARD Archaeologists led by Alan Hunter Blair, on behalf of Angus Council in advance of their development of two football pitches at Carnoustie.

Each individual object in the hoard is significant but the presence of gold ornament on the spearhead makes this an exceptional group. Within Britain and Ireland, only a handful of such spearheads are known - among them a weapon hoard found in 1963 at Pyotdykes Farm to the west of Dundee. These two weapon hoards from Angus - found only a few kilometres apart - hint at the wealth of the local warrior society during the centuries around 1000-800 BC.

There are two more aspects that elevate the Carnoustie discovery to international significance. The first aspect is the extremely rare survival of organic remains. A leather and wooden scabbard encased the Carnoustie sword and is probably the best preserved Late Bronze Age sword scabbard ever found in Britain. Fur skin survives around the spearhead, and textile around the pin and scabbard. Such organic remains rarely survive on dryland sites.

The second aspect is that the hoard is not an isolated find but was buried within a Late Bronze Age settlement, which means that once the excavation has been completed it will be possible to study the archaeological context of the hoard, revealing new insights into the local Bronze Age community that buried it. Not least of which was the longevity of settlement here. For the excavation has also revealed the largest Neolithic hall so far found in Scotland, a building dating to around 4000 BC and that may have been as old to the people who buried the weapon hoard, as they are to us.

‘It is very unusual to recover such artefacts in a modern archaeological excavation, which can reveal so much about the context of its burial. Owing to the fragile nature of these remains when we first discovered them, our team removed the entire pit, and the surrounding subsoil which it was cut into, as a single 80 kg block of soil,' said GUARD Project Officer Alan Hunter Blair. 'This was then delivered to our Finds Lab where it was assessed by a specialist Finds Conservator to plan how it could be carefully excavated and the artefacts conserved.’

'Organic evidence like Bronze Age wooden scabbards rarely survive so this just underlines how extraordinary these finds are,' said GUARD Project Officer, Beth Spence, who undertook the excavation of the hoard in GUARD Archaeology’s Finds Lab along with Conservator Will Murray from the Scottish Conservation Studio.

Along with the hoard, the GUARD Archaeology team have discovered around 1000 archaeological features, among them the remains of up to 12 sub-circular houses that probably date to the Bronze Age along with the remains of 2 rectilinear halls that likely date to the Neolithic period. Some of the other archaeology on site consists of clusters of large pits containing discarded, broken pots and lithic artefacts. It is unclear yet if the archaeological remains comprise a settlement that lasted from the Neolithic until the Late Bronze Age or if it comprises several settlements built upon the same site but separated in time by many centuries.

Claire Herbert of ACAS, Archaeological advisers to Angus Council, said ‘The archaeology uncovered at Carnoustie is undoubtedly of national and international significance, and will certainly further enhance our knowledge of the prehistory of this area, providing an invaluable opportunity to learn more about how people in Angus lived in the Neolithic and Bronze Age.’

Angus Council communities convener Donald Morrison added: ‘It is clear that Carnoustie was as much a hive of activity in Neolithic and Bronze Age times as it is now. The discoveries made on land destined for sporting development have given us a fascinating insight into our Angus forebears and I look forward to learning more about our local prehistory.’

Vice convener Jeanette Gaul said: ‘To make such a find while preparing to create sports facilities for Carnoustie came as a huge surprise to us all. We’ve since learned it is of national and, indeed, international importance. But I am pleased that the archaeologists have involved local young people in the excavation project and are offering us all an insight into Angus’ distant past.’

Thursday, February 23, 2017

Neanderthal DNA contributes to human gene expression


 



This visual abstract depicts the findings of McCoy et al., who show genome-wide interrogation of the functional differences between modern human and Neanderthal alleles reveals that Neanderthal-inherited sequences are not silent remnants of ancient interbreeding but have a measurable impact on gene expression that may contribute to phenotypic variation in modern humans.
CREDIT
McCoy et al./Cell 2017

The last Neanderthal died 40,000 years ago, but much of their genome lives on, in bits and pieces, through modern humans. The impact of Neanderthals' genetic contribution has been uncertain: Do these snippets affect our genome's function, or are they just silent passengers along for the ride? In Cell on February 23, researchers report evidence that Neanderthal DNA sequences still influence how genes are turned on or off in modern humans. Neanderthal genes' effects on gene expression likely contribute to traits such as height and susceptibility to schizophrenia or lupus, the researchers found.

"Even 50,000 years after the last human-Neanderthal mating, we can still see measurable impacts on gene expression," says geneticist and study co-author Joshua Akey of the University of Washington School of Medicine. "And those variations in gene expression contribute to human phenotypic variation and disease susceptibility."

Previous studies have found correlations between Neanderthal genes and traits such as fat metabolism, depression, and lupus risk. However, figuring out the mechanism behind the correlations has proved difficult. DNA can be extracted from fossils and sequenced, but RNA cannot. Without this source of information, scientists can't be sure exactly if Neanderthal genes functioned differently than their modern human counterparts. They can, however, look to gene expression in modern humans who possess Neanderthal ancestry.

In this study, researchers analyzed RNA sequences in a dataset called the Genotype-Tissue Expression (GTEx) Project, looking for people who carried both Neanderthal and modern human versions of any given gene--one version from each parent. For each such gene, the investigators then compared expression of the two alleles head-to-head in 52 different tissues.

"We find that for about 25% of all those sites that we tested, we can detect a difference in expression between the Neanderthal allele and the modern human allele," says the study's first author, UW postdoctoral researcher Rajiv McCoy.

Expression of Neanderthal alleles tended to be especially low in the brain and the testes, suggesting that those tissues may have experienced more rapid evolution since we diverged from Neanderthals approximately 700,000 years ago. "We can infer that maybe the greatest differences in gene regulation exist in the brain and testes between modern humans and Neanderthals," says Akey.

One example uncovered by this study is a Neanderthal allele of a gene called ADAMTSL3 that decreases risk of schizophrenia, while also influencing height. "Previous work by others had already suggested that this allele affects alternative splicing. Our results support this molecular model, while also revealing that the causal mutation was inherited from Neanderthals," says McCoy. Alternative splicing refers to a process in which mRNAs are modified before they leave the cell's nucleus. When the Neanderthal mutation is present, the cell's machinery removes a segment of the mRNA that is expressed in the modern human version. The cell ends up making a modified protein because of a single mutation from a Neanderthal ancestor.

The connection between that modified protein, height, and schizophrenia still requires more investigation, but it's an example of how small differences between modern humans and Neanderthals can contribute to variation in people.

"Hybridization between modern humans and Neanderthals increased genomic complexity," explains Akey. "Hybridization wasn't just something that happened 50,000 years ago that we don't have to worry about anymore. Those little bits and pieces, our Neanderthal relics, are influencing gene expression in pervasive and important ways."

Next steps may include investigating whether Denisovans--another species of hominins that crossbred with modern humans--are contributing to gene expression, as well as applying the side-by-side method of expression analysis more broadly. For this study, McCoy and his colleagues had to develop a new statistical approach to sift through the immense amount of RNA data, but the same technique could be used to compare gene expression differences between modern human alleles.

Tuesday, February 21, 2017

Radiocarbon dating and DNA show ancient Puebloan leadership in the maternal line


Discovering who was a leader, or even if leaders existed, from the ruins of archaeological sites is difficult, but now a team of archaeologists and biological anthropologists, using a powerful combination of radiocarbon dating and ancient DNA, have shown that a matrilineal dynasty likely ruled Pueblo Bonito in New Mexico for more than 300 years.

"We are not saying that this was a state-level society," said Douglas J. Kennett, head and professor of anthropology, Penn State. "But we don't think it was egalitarian either."

Archaeologists have described the Chaco Phenomenon as anything from an egalitarian society without any rulers at all, to a full-fledged state-level society or kingdom. The researchers now think that Chaco Canyon was much more than a leaderless conglomeration of people, but a hierarchically organized society with leadership inherited through the maternal line.

Typically, the only things found in prehistoric archaeological ruins to indicate elevated status are grave goods -- the artifacts found with burials. Throughout the Southwest it is unusual to find formal burials within structures, because most people were buried with limited grave goods outside housing compounds, but in excavations sponsored by the American Museum of Natural History and carried out in the 1890s at Chaco Canyon, archaeologists found room 33 in Pueblo Bonito -- a burial crypt within a 650-room pueblo dating between 800 and 1130 -- that contained 14 burials.

"It has been clear for some time that these were venerated individuals, based on the exceptional treatment they received in the afterlife -- most Chacoans were buried outside of the settlement and never with such high quantities of exotic goods," said Adam Watson, postdoctoral fellow in the American Museum of Natural History Division of Anthropology. "But previously one could only speculate about the exact nature of their relationship to one another."

The researchers note in today's (Feb. 21) issue of Nature Communications, that this 6.5 by 6.5 foot room "was purposely constructed as a crypt for a high-status member of this nascent community and ultimately his lineal descendants." The initial burial was of a male in his 40s who died from a lethal blow to the head. He was buried with more than 11,000 turquoise beads, 3,300 shell beads and other artifacts including abalone shells and a conch shell trumpet originating from the Pacific Ocean and Gulf of California far from central New Mexico. This burial is the richest ever found in the American Southwest.

Another individual was buried above this initial interment and a split plank floor placed above them. In the space above, another 12 burials took place over the span of 300 years.

"We originally worked with Steve Plog (David A. Harrison Professor of Archaeology, University of Virginia) to radiocarbon date these burials," said Kennett. "The results of this work had all the Individuals dating to a 300 year period. Then the question came up, are they related?"

Kennett and Plog teamed up with George Perry, assistant professor of anthropology and biology, Penn State and Richard George, a graduate student in anthropology, to first examine the mitochondrial genomes of these individuals."

When the results came back, the researchers found that all the individuals shared the same mitochondrial genome sequence. Mitochondrial DNA (mtDNA) is inherited only from an individual's mother, so matching mtDNA indicates that not only where all the individuals from the same family, but the inheritance was matrilineal -- through the mother.

"First we thought this could be some kind of contamination problem," said Kennett. "We checked for contamination, but found no evidence for it and David Reich's laboratory at Harvard Medical School corroborated our results."

Working with Reich, professor of genetics, the researchers then wondered if they could determine specific relationships among these individuals.

"Using DNA sequences from the nuclear genome combined with the radiocarbon dates, we identified a mother-daughter pair and a grandmother-grandson relationship," said Kennett.

"For the first time, we're saying that one kinship group controlled Pueblo Bonito for more than 300 years," said Plog "This is the best evidence of a social hierarchy in the ancient Southwest."