DNA study links indigenous Brazilians to Polynesians

Sequences shared by far-away populations stir up a Palaeoamerican mystery.

Indigenous people that lived in southeastern Brazil in the late 1800s shared some genetic sequences with Polynesians, an analysis of their remains shows. The finding offers some support for the possibility that Pacific islanders traded with South America thousands of years ago, but researchers say that the distinctive DNA sequences, or haplogroups, may have entered the genomes of the native Brazilians through the slave trade during the nineteenth century.

Most scientists agree that humans arrived in the Americas between 15,000 and 20,000 years ago, probably via the Bering land bridge linking northeastern Asia with what is now Alaska. But the precise timing and the number of ‘migration waves’ is unclear, owing largely to variations in early Americans’ physical features, says Sérgio Pena, a molecular geneticist at the Federal University of Minas Gerais in Belo Horizonte, Brazil.

One broad group of these Palaeoamericans — the Botocudo people, who lived in inland regions of southeastern Brazil — stands out, having skull shapes that were intermediate between those of other Palaeoamericans and a presumed ancestral population in eastern Asia.

Now, a genetic analysis sheds light on the possible heritage of the Botocudo. Pena and his colleagues studied short stretches of mitochondrial DNA (mtDNA) in samples drilled from teeth in 14 Botocudo skulls kept in a museum collection in Rio de Janeiro. By analysing material from inside the teeth, the team minimized the possibility of contamination with DNA from the numerous people who have probably handled the skulls since they arrived at the museum in the late 1800s.

The mtDNA from 12 of the skulls matched a well-known Palaeoamerican haplogroup. But mtDNA from two of the skulls included a haplogroup commonly found in Polynesia, Easter Island and other Pacific island archipelagos, the researchers report today in Proceedings of the National Academy of Sciences1. A separate lab confirmed the result with samples from one of the skulls, indicating that the ‘Polynesian haplogroup’ did not result from contamination, the researchers contend.

“But to call that haplogroup Polynesian is a bit of a misnomer,” says Lisa Matisoo-Smith, a molecular anthropologist at the University of Otago in Dunedin, New Zealand. The haplogroup is also found — albeit at a lower frequency — in populations living as far west as Madagascar.

Nevertheless, says Pena, it is a mystery how DNA from Palaeoamericans living in southeastern Brazil could include gene sequences typically found in Pacific islanders. “We have this finding,” he says. “Now we have to explain it.”

The researchers say that it is possible — but unlikely — that the DNA could have come from Polynesians who voyaged from remote islands to the western coast of South America. Those traders or their progeny would then have made their way to southeastern Brazil and settled or interbred with natives. But that, too, is improbable, says Pena, because the Andes are a formidable barrier that west coast residents typically did not climb or cross. Although researchers have suggested that ancestors of some species of chickens made their way to Chile through trade with pre-Columbian seafarers from Polynesia2, a subsequent study3 poked holes in that conclusion.

The researchers also entertain scenarios in which the haplogroup arrived in South America via the slave trade. Around 2,000 Polynesians were brought to Peru in the 1860s, and some could have ended up in Brazil, although the researchers say that they are not aware of any evidence that this occurred. And between 1817 and 1843, approximately 120,000 slaves were shipped from Madagascar to Brazil — and some of them were probably transported to areas where the Botocudo also lived. Although the researchers consider the latter scenario to be the most probable, Pena says: “We currently don’t have enough evidence to definitively reject any of these scenarios.”

“This is a pretty exciting initial result,” says Alice Storey, an archaeologist at the University of New England in Armidale, Australia. Further studies of genetic material from the skulls, including detailed analyses of nuclear DNA (which contains much longer genetic sequences than mtDNA), could offer more insight into the mysterious ancestry of the Botocudo, she says.
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References:

Perkins, Sid. 2013. “DNA study links indigenous Brazilians to Polynesians”. Nature. Posted: April 1, 2013. Available online: http://www.nature.com/news/dna-study-links-indigenous-brazilians-to-polynesians-1.12710

Article Reference:

1. Gonçalves, V. F. et al. Proc. Natl Acad. Sci. USA http:dx.doi.org/10.1073/pnas.1217905110 (2013).

2. Storey, A. A. et al. Proc. Natl Acad. Sci. USA 104, 10335–10339 (2007).

3. Gongora, J. et al. Proc. Natl Acad. Sci. USA 105, 10308–10313 (2008).

How to Dance Like a 19th-Century Japanese Man

Compact, paper-bound, picture-filled books of Japan's Edo period helped democratize reading — and apparently dance lessons — for those living under the strict rule of shoguns from 1615 to 1868.

These beautiful wood-block illustrated books, called "ehon," circulated widely, and examples of the volumes are currently on display at the Smithsonian’s Arthur M. Sackler Gallery in Washington, D.C., as part of an exhibit called "Hand-Held: Gerhard Pulverer’s Japanese Illustrated Books."

One of the highlights of this show is an 1815 book called "Odori Hitori Geiko," translated as "Dance Instruction Manual," or "Practice Dancing Alone." The manual acts like a step-by-step guide for some traditional dance sequences, and it was illustrated by Katsushika Hokusai, the Japanese artist credited with one of the most recognizable images of the past 200 years: "The Great Wave off Kanagawa."

The Smithsonian Institute made a mesmerizing moving gif of the dance steps in action.

Pulverer's collection of more than 2,000 Japanese printed books was acquired in its entirety in 2007 by the Smithsonian. The exhibition is on view until Aug. 11.
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References:

Gannon, Megan. 2013. “How to Dance Like a 19th-Century Japanese Man”. Live Science. Posted: April 11, 2013. Available online: http://www.livescience.com/28666-japanese-dance-manual.html?cmpid=514627

Ancient mysteries revealed in Turkmen desert sands

Over four millennia ago, the fortress town of Gonur-Tepe might have been a rare advanced civilisation before it was buried for centuries under the dust of the Kara Kum desert in remote western Turkmenistan.

After being uncovered by Soviet archaeologists in the last century, Gonur-Tepe, once home to thousands of people and the centre of a thriving region, is gradually revealing its mysteries with new artifacts being uncovered on every summer dig.

The scale of the huge complex which spans some 30 hectares can only be properly appreciated from the air, from where the former buildings look like a maze in the desert surrounded by vast walls.

Just 50 kilometres (30 miles) from the celebrated ancient city of Merv outside the modern city of Mary, the ruins of Gonur-Tepe are an indication of the archeological riches of Turkmenistan, one of the most isolated countries in the world.

Around 2,000 BC, Gonur-Tepe was the main settlement of the Margush or Margiana region that was home to one of the most sophisticated, but little-known Bronze Age civilisations.

The site -- which until the last century was covered by desert and scrub -- was uncovered in Soviet times by the celebrated archeologist Viktor Sarianidi who, at the age of 84, is about to spend another summer working on the site.

"I remember so well my joy when I first encountered this archaeological Klondike. A sensation right under your feet," the Russian professor told AFP.

Every digging season at Gonur-Tepe yields new discoveries showing the quality of the craftsmanship of the Bronze Age artisans in the town which at the time would likely have been home to thousands of residents.

The town's craftsmen could mould metal, make silver and gold trinkets, create materials for cult worship and carve bone and stone.

"It's amazing to what extent the people possessed advanced techniques. The craftsmen learned how to change the form of natural stone at a high temperature and then glazed it so that it was preserved," said archeologist Nadezhda Dubova.

"This year, Gonur has given us another surprise, a fantastic mosaic," she said, noting that such an object pre-dated the standard era of mosaic-making in Greek and Roman antiquity.

The ruins of Gonur-Tepe are the centrepiece of a network of towns and settlements in the delta region of the river Morghab that flows through Turkmenistan from its source in Afghanistan.

Gonur-Tepe is a three-hour drive from the provincial centre of Mary -- two hours along a bumpy asphalt road that passes former collective farms that have now fallen into disuse, and then another hour-long slog through the desert scrub.

Mary, 380 kilometres from the capital Ashgabat, is a typical Turkmen provincial city, home to 200,000 people and largely built in the Soviet style with a railway connection and low-rise apartment buildings.

Some 30 kilometres (19 miles) outside Mary lies the other great glory of the region -- the great ruined city of Merv, whose importance goes back to the time of the Achaemenid Persians and reached a peak under Turkic rule in the 12th century AD.

Merv went into terminal decline after it was sacked by the Mongols in 1221 in a deadly conquest that left tens of thousands dead. Its ruins are as deserted as those of Gonur-Tepe.

Its greatest treasure is the still preserved mausoleum of the Seljuk Sultan Sanjar under whose rule Merv was a city of 200,000 people and briefly one of the most heavily populated settlements in the world.

The mausoleum, which is crowned by a cupola with a diameter of over 17 metres, was revolutionary in its design, Turkmen architectural historian Ruslan Muradov told AFP.

The design of the dome "anticipates by 300 years the ideas of the great Renaissance architect Filippo Brunelleschi" who designed the great dome of the cathedral in Florence, he said.

Unlike the ruins of Gonur-Tepe, ancient Merv was excavated as far back as Tsarist times when today's Turkmenistan was a far-flung outpost of the Russian Empire. It has been listed as a World Heritage Site by UNESCO since 1999.

Archaeologists have only just begun to scratch the surface of the huge riches of the Mary region, said Viktor Turik, a historian who works at the Mary history museum.

"In the region there are 354 archeological monuments, 95 percent of which have, until now, not been studied by experts," he said.

Turkmenistan remains one of the most isolated countries in the world but still sees a trickle of foreign tourists every year, mostly on organised special interest tours.

Mary has just three hotels although President Gurbanguly Berdymukhamedov has recently ordered the construction of a new 350-bed hotel in an apparent bid to boost tourism.

Meanwhile the question remains about what to do with the extraordinary silver and gold artefacts that are being unearthed in the region but which need painstaking restoration and conservation.

An employee of Turkmenistan's national heritage department said a joint project had been mooted with the antiquities department of the Louvre in Paris, but had fallen through.

"Many unique discoveries which are like nothing in the world are waiting their moments in the storage departments of Turkmen museums," said the employee who asked not to be named.
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References:

France 24. 2013. “Ancient mysteries revealed in Turkmen desert sands”. France 24. Posted: April 6, 2013. Available online: http://www.france24.com/en/20130406-ancient-mysteries-revealed-turkmen-desert-sands

First Love Child of Human, Neanderthal Found

The skeletal remains of an individual living in northern Italy 40,000-30,000 years ago are believed to be that of a human/Neanderthal hybrid, according to a paper in PLoS ONE.

If further analysis proves the theory correct, the remains belonged to the first known such hybrid, providing direct evidence that humans and Neanderthals interbred. Prior genetic research determined the DNA of people with European and Asian ancestry is 1 to 4 percent Neanderthal.

The present study focuses on the individual’s jaw, which was unearthed at a rock-shelter called Riparo di Mezzena in the Monti Lessini region of Italy. Both Neanderthals and modern humans inhabited Europe at the time.

“From the morphology of the lower jaw, the face of the Mezzena individual would have looked somehow intermediate between classic Neanderthals, who had a rather receding lower jaw (no chin), and the modern humans, who present a projecting lower jaw with a strongly developed chin,” co-author Silvana Condemi, an anthropologist, told Discovery News.

Condemi is the CNRS research director at the University of Ai-Marseille. She and her colleagues studied the remains via DNA analysis and 3D imaging. They then compared those results with the same features from Homo sapiens.

The genetic analysis shows that the individual’s mitochondrial DNA is Neanderthal. Since this DNA is transmitted from a mother to her child, the researchers conclude that it was a “female Neanderthal who mated with male Homo sapiens.”

By the time modern humans arrived in the area, the Neanderthals had already established their own culture, Mousterian, which lasted some 200,000 years. Numerous flint tools, such as axes and spear points, have been associated with the Mousterian. The artifacts are typically found in rock shelters, such as the Riparo di Mezzena, and caves throughout Europe.

The researchers found that, although the hybridization between the two hominid species likely took place, the Neanderthals continued to uphold their own cultural traditions.

That's an intriguing clue, because it suggests that the two populations did not simply meet, mate and merge into a single group.

As Condemi and her colleagues wrote, the mandible supports the theory of "a slow process of replacement of Neanderthals by the invading modern human populations, as well as additional evidence of the upholding of the Neanderthals' cultural identity.”

Prior fossil finds indicate that modern humans were living in a southern Italy cave as early as 45,000 years ago. Modern humans and Neanderthals therefore lived in roughly the same regions for thousands of years, but the new human arrivals, from the Neanderthal perspective, might not have been welcome, and for good reason. The research team hints that the modern humans may have raped female Neanderthals, bringing to mind modern cases of "ethnic cleansing."

Ian Tattersall is one of the world’s leading experts on Neanderthals and the human fossil record. He is a paleoanthropologist and a curator emeritus at the American Museum of Natural History.

Tattersall told Discovery News that the hypothesis, presented in the new paper, “is very intriguing and one that invites more research.”

Neanderthal culture and purebred Neanderthals all died out 35,000-30,000 years ago.
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References:

Viegas, Jennifer. 2013. “First Love Child of Human, Neanderthal Found”. Discovery News. Posted: March 27, 2013. Available online: http://news.discovery.com/human/evolution/neanderthal-skeleton-provides-evidence-of-interbreeding-with-humans-130327.htm

Holocene Epoch: The Age of Man

The Holocene Epoch is the current period of geologic time. Another term that is sometimes used is the Anthropocene Epoch, because its primary characteristic is the global changes caused by human activity. This term can be misleading, though; modern humans were already well established long before the epoch began. The Holocene Epoch began 12,000 to 11,500 years ago at the close of the Paleolithic Ice Age and continues through today.

As Earth entered a warming trend, the glaciers of the late Paleolithic retreated. Tundra gave way to forest. As the climate changed, the very large mammals that had adapted to extreme cold, like mammoth and wooly rhinoceros, became extinct. Humans, once dependent on these “mega mammals” for much of their food, switched to smaller game and increased their gathering of plant materials to supplement their diet.

Evidence indicates that about 10,800 years ago, the climate underwent a sharp cold turn lasting for several years. The glaciers did not return, but game and plant materials would have been scarce. As temperatures began to rebound, human population began to increase and we began inventing the processes that would change the planet forever.

Agriculture takes root

Agriculture is one of the primary ways in which human activity has impacted the planet. By 8000 B.C., the cultivation of wheat, barley and other plants had spread from its origins in the Fertile Crescent through much of the Indo/European world. Domestication of sheep, goats and cattle began at about the same time. In Central and South America, the most commonly domesticated plants were maize, bottle gourds, squash and beans. Farming seems to have gotten a later start in Asia. Current evidence suggests that it may have been introduced to China by trade with Indo/European tribes, although it appears to have been common by the time of the start of the Shang Dynasty in about 1675 B.C.

Until the advent of agriculture and urbanization, the human population was largely limited by the same factors that limit other living organisms. Limiting factors in the environment, such as availability of food, water and shelter, evolutionary relationships like predator/prey ratios or presence of pathogens provide natural balances to populations. A population will generally expand until it reaches the carrying capacity, the maximum number of individuals an environment can support without detrimental effects, at which time it will level off.  Continued expansion beyond the carrying capacity generally results in a crash (a rapid decline to a level far below the carrying capacity). If enough genetic diversity remains the population may recover; it may also become extinct.

Beginning about the first century A.D., humans began to sidestep these restraints. Agriculture had increased the number of people that could be supported by the environment; we were the first animals to increase the carrying capacity of our existing habitat. Population slowly began to rise. There were approximately 170 million people on Earth at the end of the first century; by 1800, the population was over 1 billion. The Industrial Revolution of the 19th century allowed human populations to grow exponentially. Industrialization, improved sanitation and medical care caused death rates to decline, while birth rates continued to climb in most parts of the world. Science has continued to help us increase the carrying capacity of the planet, but not the size of the planet.

Holocene extinction

Pressure from the human population has had far-reaching effects on the biodiversity of the planet. Earth has undergone at least five major mass extinction events (times when at least 60 percent of extant genera became extinct within a span of no more than a few hundred thousand years.) Most people are familiar with the last mass extinction that closed the Cretaceous Period 65 million years ago and resulted in the extinction of the dinosaurs. Many scientists believe we are in the midst of a sixth mass extinction event caused by ourselves. Based on population numbers required to maintain genetic viability; it is estimated that as many as 30 percent of plant and animal species may become extinct within the next 100 years. Habitat destruction is the leading cause of species extinction today.

We have also had significant impacts on the geophysical characteristics of Earth. Monoculture (devoting large tracts of land to single crops) has affected the composition and fertility of the soil in most arable parts of the world. This effect has been ameliorated by use of chemical fertilizers, but has not been eliminated. Depletion of aquifers has reduced the availability of free fresh water.

We base our division of geologic time on evidence of changes in the life forms present on Earth in different times. In the past, global climate change has often been synchronous with mass extinction. Although there is some controversy about whether humans are part of the cause for the current global warming trend, there is no doubt that Earth is experiencing climate change. We may be nearing the end of the Holocene Epoch.
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References:

Bagley, Mary. 2013. “Holocene Epoch: The Age of Man”. Live Science. Posted: March 27, 2013. Available online: http://www.livescience.com/28219-holocene-epoch.html

Artifacts shed light on social networks of the past

Researchers studied thousands of ceramic and obsidian artifacts from A.D. 1200-1450 to learn about the growth, collapse and change of social networks in the late pre-Hispanic Southwest

The advent of social networking sites like Facebook and Twitter have made us all more connected, but long-distance social networks existed long before the Internet.

An article published this week in the Proceedings of the National Academy of Sciences sheds light on the transformation of social networks in the late pre-Hispanic American Southwest and shows that people of that period were able to maintain surprisingly long-distance relationships with nothing more than their feet to connect them.

Led by University of Arizona anthropologist Barbara Mills, the study is based on analysis of more than 800,000 painted ceramic and more than 4,800 obsidian artifacts dating from A.D. 1200-1450, uncovered from more than 700 sites in the western Southwest, in what is now Arizona and western New Mexico.

With funding from the National Science Foundation, Mills, director of the UA School of Anthropology, worked with collaborators at Archeology Southwest in Tucson to compile a database of more than 4.3 million ceramic artifacts and more than 4,800 obsidian artifacts, from which they drew for the study.

They then applied formal social network analysis to see what material culture could teach them about how social networks shifted and evolved during a period that saw large-scale demographic changes, including long-distance migration and coalescence of populations into large villages.

Their findings illustrate dramatic changes in social networks in the Southwest over the 250-year period between A.D. 1200 and 1450. They found, for example, that while a large social network in the southern part of the Southwest grew very large and then collapsed, networks in the northern part of the Southwest became more fragmented but persisted over time.

"Network scientists often talk about how increasingly connected networks become, or the 'small world' effect, but our study shows that this isn't always the case," said Mills, who led the study with co-principal investigator and UA alumnus Jeffery Clark, of Archaeology Southwest.

"Our long-term study shows that there are cycles of growth and collapse in social networks when we look at them over centuries," Mills said. "Highly connected worlds can become highly fragmented."

Another important finding was that early social networks do not appear to have been as restricted as expected by settlements' physical distance from one another. Researchers found that similar types of painted pottery were being created and used in villages as far as 250 kilometers apart, suggesting people were maintaining relationships across relatively large geographic expanses, despite the only mode of transportation being walking.

"They were making, using and discarding very similar kinds of assemblages over these very large spaces, which means that a lot of their daily practices were the same," Mills said. "That doesn't come about by chance; it has to come about by interaction – the kind of interaction where it's not just a simple exchange but where people are learning how to make and how to use and ultimately discard different kinds of pottery."

"That really shocked us, this idea that you can have such long distance connections. In the pre-Hispanic Southwest they had no real vehicles, they had no beasts of burden, so they had to share information by walking," she said.

The application of formal social network analysis – which focuses on the relationships among nodes, such as individuals, household or settlements – is relatively new in the field of archaeology, which has traditionally focused more on specific attributes of those nodes, such as their size or function.

The UA study shows how social network analysis can be applied to a database of material culture to illustrate changes in network structures over time.

"We already knew about demographic changes – where people were living and where migration was happening – but what we didn't know was how that changed social networks," Mills said. "We're so used to looking traditionally at distributions of pottery and other objects based on their occurrence in space, but to see how social relationships are created out of these distributions is what network analysis can help with."

One of Mills's collaborators on the project was Ronald Breiger, renowned network analysis expert and a UA professor of sociology, with affiliations in statistics and government and public policy, who says being able to apply network analysis to archaeology has important implications for his field.

"Barbara (Mills) and her group are pioneers in bringing the social network perspective to archaeology and into ancient societies," said Breiger, who worked with Mills along with collaborators from the UA School of Anthropology; Archaeology Southwest; the University of Wisconsin; Hendrix College; the University of Colorado, Boulder; the Santa Fe Institute; and Archaeological XRF Laboratory in Albuquerque, N.M.

"What archaeology has to offer for a study of networks is a focus on very long-term dynamics and applications to societies that aren't necessarily Western, so that's broadening to the community of social network researchers," Breiger said. "The coming together of social network and spatial analysis and the use of material objects to talk about culture is very much at the forefront of where I see the field of social network analysis moving."

Going forward, Mills hopes to use the same types of analyses to study even older social networks. "We have a basis for building on, and we're hoping to get even greater time depth. We'd like to extend it back in time 400 years earlier," she said. "The implications are we can see things at a spatial scale that we've never been able to look at before in a systematic way. It changes our picture of the Southwest."
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References:

EurekAlert. 2013. “Artifacts shed light on social networks of the past”. EurekAlert. Posted: March 25, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/uoa-asl032513.php

Nouns before verbs?

New research agenda could help shed light on early language, cognitive development

Researchers are digging deeper into whether infants' ability to learn new words is shaped by the particular language being acquired.

A new Northwestern University study cites a promising new research agenda aimed at bringing researchers closer to discovering the impact of different languages on early language and cognitive development.

For decades, researchers have asked why infants learn new nouns more rapidly and more easily than new verbs. Many researchers have asserted that the early advantage for learning nouns over verbs is a universal feature of human language.

In contrast, other researchers have argued that early noun-advantage is not a universal feature of human language but rather a consequence of the particular language being acquired.

Sandra Waxman, lead author of the study and Louis W. Menk Professor of Psychology at Northwestern, shows in her research that even before infants begin to produce many verbs in earnest, infants acquiring either noun-friendly or verb-friendly languages already appreciate the concepts underlying both noun and verb meaning.

In all languages examined to date, researchers see a robust ability to map nouns to objects, Waxman said, but when it comes to mapping verbs to events, infants' performance is less robust and more variable. Their ability to learn new verbs varied not only as a function of the native language being acquired, but also with the particular linguistic context in which the verb was presented.

Based on new evidence, a shift in the research agenda is necessary, according to Waxman and her colleagues.

"We now know that by 24 months infants acquiring distinctly different languages can successfully map novel nouns to objects and novel verbs to event categories," Waxman said. "It is essential that we shift the research focus to include infants at 24 months and younger, infants who are engaged in the very process of acquiring distinctly different native languages."

Waxman said the implications are clear. "Rather than characterizing languages as either 'noun friendly' or 'verb friendly,' it would be advantageous to adopt a more nuanced treatment of the syntactic, semantic, morphologic and pragmatic properties of each language and the consequences of these properties on infants' acquisition of linguistic structure and meaning."
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References:

EurekAlert. 2013. “Nouns before verbs?”. EurekAlert. Posted: March 25, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/nu-nbv032513.php