Wednesday, October 18, 2017

Research sheds new light on early turquoise mining in Southwest



Turquoise is an icon of the desert Southwest, with enduring cultural significance, especially for Native American communities. Yet, relatively little is known about the early history of turquoise procurement and exchange in the region.

University of Arizona researchers are starting to change that by blending archaeology and geochemistry to get a more complete picture of the mineral's mining and distribution in the region prior to the 16th-century arrival of the Spanish.

In a new paper, published in the November issue of the Journal of Archaeological Science, UA anthropology alumnus Saul Hedquist and his collaborators revisit what once was believed to be a relatively small turquoise mine in eastern Arizona. Their findings suggest that the Canyon Creek mine, located on the White Mountain Apache Indian Reservation, was actually a much more significant source of turquoise than previously thought.

With permission from the White Mountain Apache Tribe, Hedquist and his colleagues visited the now essentially exhausted Canyon Creek source -- which has been known to archaeologists since the 1930s -- to remap the area and collect new samples. There, they found evidence of previously undocumented mining areas, which suggest the output of the mine may have been 25 percent higher than past surveys indicated.

"Pre-Hispanic workings at Canyon Creek were much larger than previously estimated, so the mine was clearly an important source of turquoise while it was active," said Hedquist, lead author of the paper, who earned his doctorate from the UA School of Anthropology in the College of Social and Behavioral Sciences in May.

In addition, the researchers measured ratios of lead and strontium isotopes in samples they collected from the mine, and determined that Canyon Creek turquoise has a unique isotopic fingerprint that distinguishes it from other known turquoise sources in the Southwest. The isotopic analysis was conducted in the lab of UA College of Science Dean Joaquin Ruiz in the Department of Geosciences by study co-author and UA geosciences alumna Alyson Thibodeau. Now an assistant professor at Dickinson College in Pennsylvania, Thibodeau did her UA dissertation on isotopic fingerprinting of geological sources of turquoise throughout the Southwest.

"If you pick up a piece of turquoise from an archaeological site and say 'where does it come from?' you have to have some means of telling the different turquoise deposits apart," said David Killick, UA professor of anthropology, who co-authored the paper with Hedquist, Thibodeau and John Welch, a UA alumnus now on the faculty at Simon Fraser University. "Alyson's work shows that the major mining areas can be distinguished by measurement of major lead and strontium isotopic ratios."

Based on the isotopic analysis, researchers were able to confidently match turquoise samples they collected at Canyon Creek to several archaeological artifacts housed in museums. Their samples matched artifacts that had been uncovered at sites throughout much of east-central Arizona -- some more than 100 kilometers from the mine -- suggesting that distribution of Canyon Creek turquoise was broader than previously thought, and that the mine was a significant source of turquoise for pre-Hispanic inhabitants of the Mogollon Rim area.

The researchers also were able to pinpoint when the mine was most active. Their samples matched artifacts found at sites occupied between A.D. 1250-1400, suggesting the mine was primarily used in the late 13th and/or 14th centuries.

"Archaeologists have struggled for decades to find reliable means of sourcing archaeological turquoise -- linking turquoise artifacts to their geologic origin -- and exploring how turquoise was mined and traded throughout the greater pre-Hispanic Southwest," said Hedquist, who now lives in Tempe, Arizona, and works as an archaeologist and ethnographer for Logan Simpson Inc., a cultural resources consulting firm. "We used both archaeology and geochemistry to document the extent of workings at the mine, estimate the amount of labor spent at the mine and identify turquoise from the mine in archaeological assemblages."

Research Paves Way for Future Studies 

Turquoise is a copper mineral, found only immediately adjacent to copper ore deposits. While detailed documentation of pre-Hispanic turquoise mines is limited, the work at Canyon Creek could pave the way for future investigations.

"I think our study raises the bar a bit by combining archaeological and geochemical analyses to gain a more complete picture of operations at one mine: when it was active, how intensely it was mined and how its product moved about the landscape," Hedquist said. "Researchers have only recently developed a reliable means of sourcing the mineral, so there's plenty of potential for future research."

Similar work involving the UA is already underway to explore the origin of turquoise artifacts found at the Aztec capital of Tenochtitlan in Mexico.

"Canyon Creek is but one of many ancient turquoise mines," Hedquist said. "This study provides a standard for the detailed documentation of ancient mineral procurement and a framework for linking archaeological turquoise to specific geologic locations. Building on other archaeological patterns -- the circulation of pottery and flaked stone artifacts, for example -- we can piece together the social networks that facilitated the ancient circulation of turquoise in different times and places."

A better understanding of the pre-Hispanic history of turquoise is important not only to archaeologists and mining historians but to modern Native Americans, Killick said.

"It's of great interest to modern-day Apache, Zuni and Hopi, whose ancestors lived in this area, because turquoise continues to be ritually important for them," he said. "They really have shown a great deal of interest in this work, and they've encouraged it."

Friday, October 13, 2017

40,000-year-old man in China reveals complicated genetic history of Asia Chinese Academy


The biological makeup of humans in East Asia is shaping up to be a very complex story, with greater diversity and more distant contacts than previously known, according to a new study in Current Biology analyzing the genome of a man that died in the Tianyuan Cave near Beijing, China 40,000 years ago. His bones had enough DNA molecules left that a team led by Professor FU Qiaomei, at the Molecular Paleontology Lab at the Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), could use advanced ancient DNA sequencing techniques to retrieve DNA from him that spans the human genome.

Though several ancient humans have been sequenced in Europe and Siberia, few have been sequenced from East Asia, particularly China, where the archaeological record shows a rich history for early modern humans. This new study on the Tianyuan man marks the earliest ancient DNA from East Asia, and the first ancient genome-wide data from China.

The Tianyuan man was studied in 2013 by the same lab. Then, they found that he showed a closer relationship to present-day Asians than present-day Europeans, suggesting present-day Asian history in the region extends as far back as 40,000 years ago. With new molecular techniques only published in the last two years, Professor FU and her team, in a joint collaboration with experts at the Max Planck Institute of Evolutionary Anthropology and UC Berkeley, sequenced and analyzed more regions of the genome, particularly at positions also sequenced in other ancient humans.

Since 2013, DNA generated from ancient Europeans has shown that all present-day Europeans derive some of their population history from a prehistoric population that separated from other early non-African populations soon after the migration out of Africa. The mixed ancestry of present-day Europeans could bias tests of genetic similarity, including the results found for the Tianyuan man. With the newly published data, however, the Fu lab showed that his genetic similarity to Asians remained in comparisons including ancient Europeans without mixed ancestry. They confirmed that the closest relationship he shares is with present-day Asians. That was not, however, the most exciting result they found.

With a close relationship to present-day Asians, they expected him to act similarly to present-day Asian populations with respect to Europeans. It was a surprise when they found that a 35,000-year-old individual from Belgium, GoyetQ116-1, who in other ways behaved as an ancient European, shared some genetic similarity to the Tianyuan individual that no other ancient Europeans shared. It is unlikely that this is due to direct interactions between populations near the east and west coasts of Eurasia, since other ancient Europeans do not show a similar result. Instead, the researchers suggested that the two populations represented by the Tianyuan and GoyetQ116-1 individuals derived some of their ancestry from the same sub-population prior to the European-Asian separation. The genetic relationship observed between these two ancient individuals is direct evidence that European and Asian populations have a complex history.

A second unexpected result shed some light on human genetic diversity in prehistoric East Asia. In 2015, a study comparing present-day populations in Asia, the Pacific and the Americas showed that some Native American populations from South America had an unusual connection to some populations south of mainland Asia, most notably the Melanesian Papuan and the Andamanese Onge.
That study proposed that the population that crossed into the Americas around 20,000 years ago could not be thought of as a single unit. Instead, one or more related but distinct populations crossed at around the same time period, and at least one of these groups had additional ties to an Asian population that also contributed to the present-day Papuan and Onge.

No trace of this connection is observed in present-day East Asians and Siberians, but unlike them, the Tianyuan man also possesses genetic similarities to the same South Americans, in a pattern similar to that found for the Papuan and Onge. The new study directly confirms that the multiple ancestries represented in Native Americans were all from populations in mainland Asia. What is intriguing, however, is that the migration to the Americas occurred approximately 20,000 years ago, but the Tianyuan individual is twice that age. Thus, the population diversity represented in the Americas must have persisted in mainland Asia in two or more distinct populations since 40,000 years ago.

The Tianyuan man is only one individual, but the deeper sequencing of his genome by Professor FU and her team reveals a complicated separation for ancient Europeans and Asians and hints at a diverse genetic landscape for humans in East Asia. Their study also showed that he derives from a population that is related to present-day East Asians, but is not directly ancestral to these populations, further suggesting that multiple genetically distinct populations were located in Asia from 40,000 years ago until the present.

The Tianyuan man shows us that between 40,000 years ago and the present, there are many unanswered questions about the past populations of Asia, and ancient DNA will be the key solving those questions.

Thursday, October 12, 2017


Indigenous people have been on the far northeastern edge of Canada for most of the last 10,000 years, moving in shortly after the ice retreated from the Last Glacial Maximum. Archaeological evidence suggests that people with distinct cultural traditions inhabited the region at least three different times with a possible hiatus for a period between 2,000 and 3,000 years ago.


  • This schematic shows the settlement history of Newfoundland encompassing occupations by at least three distinct cultural groups: MA, Dorset Palaeoeskimo, and Beothuk.
  • Credit

  • Produced by Deirdre Elliott with QGIS 2.18.44, and data from Stephen Hull and Natural Earth.

Now, researchers who've examined genetic evidence from mitochondrial DNA provide evidence that two of those groups, known as the Maritime Archaic and Beothuk, brought different matrilines to the island, adding further support to the notion that those groups had distinct population histories. The findings are published in Current Biology on October 12.

"Our paper suggests, based purely on mitochondrial DNA, that the Maritime Archaic were not the direct ancestors of the Beothuk and that the two groups did not share a very recent common ancestor," says Ana Duggan of McMaster University. "This in turn implies that the island of Newfoundland was populated multiple times by distinct groups."

The relationship between the older Maritime Archaic population and Beothuk hadn't been clear from the archaeological record. With permission from the current-day indigenous community, Duggan and her colleagues, led by Hendrik Poinar, examined the mitochondrial genome diversity of 74 ancient remains from the island together with the archaeological record and dietary isotope profiles. All samples were collected from tiny amounts of bone or teeth.

The sample set included a Maritime Archaic subadult more than 7,700 years old found in the L'Anse Amour burial mound, the oldest known burial mound in North America and one of the first manifestations of the Maritime Archaic tradition. The majority of the Beothuk samples came from the Notre Dame Bay area, where the Beothuk retreated in response to European expansions. Most of those samples are from people that lived on the island within the last 300 years. The DNA evidence showed that the two groups didn't share a common maternal ancestor in the recent past, but rather one that coalesces sometime in the more distant past.

"These data clearly suggest that the Maritime Archaic people are not the direct maternal ancestors of the Beothuk and thus that the population history of the island involves multiple independent arrivals by indigenous peoples followed by habitation for many generations," the researchers write. "This shows the extremely rich population dynamics of early peoples on the furthest northeastern edge of the continent."

No trace of early contact between Rapanui and South Americans in ancient DNA


IMAGE
  • IMAGE: This photograph shows moai on Rapa Nui. view more 
    Credit: Terry Hunt
Rapa Nui (Easter Island, Chile) has long been a source of intrigue and mystery. How did such a small community of people build so many impressively large statues? And what happened to cause that community to collapse? Researchers have also been curious about what kind of contact Rapa Nui's inhabitants, known as Rapanui, might have had with South Americans prior to the arrival of Europeans. Earlier evidence seemed to support early contact between the Rapanui and Native Americans .

But a new study of ancient DNA evidence collected from archaeological samples and reported in Current Biology on October 12th calls those findings back into question. The new study finds no genetic evidence that ancient inhabitants of Rapa Nui intermixed with South Americans. While the findings can't exclude the possibility that cultural contact took place between the two populations, if long-distance treks across the ocean did occur, "they did not leave genetic traces among the individual samples," said Lars Fehren-Schmitz of the University of California, Santa Cruz. "We were surprised that we didn't find any Native American admixture in our ancient Rapanui specimens."

The idea that there had been early Pacific contact with South America, or even that a Southern Pacific migration route contributed to the peopling of the Americas, has been a long-standing debate in the field. In their new study, Fehren-Schmitz and colleagues wanted to find out what DNA from ancient Rapanui samples had to say on the matter.

The researchers sequenced DNA from five individual samples representing Rapanui both before and after European contact. They report that the DNA, including both complete mitochondrial genomes and low-coverage autosomal genomes, indicates that the DNA of the sampled individuals falls within the genetic diversity of present-day and ancient Polynesians.

"We can reject the hypothesis that any of these individuals had substantial Native American ancestry," Fehren-Schmitz said. "Our data thus suggest that the Native American ancestry in contemporary Easter Islanders was not present on the island prior to European contact and may thus be due to events in more recent history."

The new study highlights the value of ancient DNA for testing hypotheses about the past. It's clear from earlier evidence that living Rapanui do have a small proportion of Native American ancestry. But, the researchers in the new study say, "it is especially difficult to disentangle movements of people in the prehistoric period from more recent times." The question remains: How and when did this population exchange happen?

The researchers say they'd now like to generate genome-wide data from additional ancient Oceania and western South American populations. The goal is to develop a more detailed picture of the populations that lived within each of these regions and potential interactions among them.

Monday, October 9, 2017

Amazon farmers discovered the secret of domesticating wild rice 4,000 years ago

                     


Amazonian farmers discovered how to manipulate wild rice so the plants could provide more food 4,000 years ago, long before Europeans colonised America, archaeologists have discovered.

Experts from the UK and Brazil have found the first evidence that ancient South Americans learned how to grow bigger rice crops with larger grains, but this expertise may have been lost after 1492 when the indigenous population was decimated, research shows.

The evidence of the success of early rice farmers on the vast wetlands near the Guaporé River in Rondônia state, Brazil, could help modern day plant breeders develop rice crops which are less susceptible to disease and more adaptable to the effects of climate change than the Asian varieties. Different species of rice were first grown approximately 11,000 years ago in the Yangtze River, China, and around 2,000 years ago in West Africa.

The University of Exeter study, funded in part by the European Research Council, also shows how important the huge wetlands and tropical forests of lowland South America were in providing food for early human settlers in South America. Ancient inhabitants managed to domesticate cassava, peanuts and chilli peppers crops for food.

The archaeologists analysed 16 samples of microscopic plant remains from ten different time periods found during excavations during 2014 led by the University of São Paulo in South West Amazonia. More phytoliths, hard, microscopic pieces of silica made by plant cells, were found at higher ground level, suggesting rice began to play a larger role in the diet of people who lived in the area - and more was farmed - as time went on.

Changes in the ratio of husk, leaf and stem remains found at different ground levels also suggest the Amazon residents became more efficient harvesters over time, bringing more grain and fewer leaves to the site. The rice grown, Oryza sp, also became bigger over time compared to the wild rice first cultivated by the South Americans. This area has been occupied by humans for at least 10,000 years.

Professor Jose Iriarte, from the University of Exeter, who led the research, said: "This is the first study to identify when wild rice first began to be grown for food in South America. We have found people were growing crops with larger and larger seeds. Even though they were also eating wild and domesticated plants including maize, palm fruits, soursop and squash, wild rice was an important food, and people began to grow it at lake or river edges.

"During a time when the climate was getting wetter and the wetlands expanding, this critical seasonal resource that is ripe at the peak of the flooding season when other resources are dispersed and scarce, residents of Monte Castelo began to grow larger rice."

Evidence for mid-Holocene rice domestication in the Americas by Lautaro Hilbert and Jose Iriarte from the University of Exeter, Elizabeth Veasey, Carlos Augusto Zimpel, Eduardo Goes Neves and Francisco Pugliese from the Universidade de São Paulo, Bronwen S. Whitney from Northumbria University and Myrtle Shock from the Universidade Federal do Oeste de Pará, is published in the journal Nature Ecology and Evolution

Friday, October 6, 2017

More traits associated with your Neandertal DNA


After humans and Neandertals met many thousands of years ago, the two species began interbreeding. Although Neandertals aren't around anymore, about two percent of the DNA in non-African people living today comes from them. Recent studies have shown that some of those Neandertal genes have contributed to human immunity and modern diseases. Now researchers reporting in the American Journal of Human Genetics on October 5th have found that our Neandertal inheritance has contributed to other characteristics, too, including skin tone, hair color, sleep patterns, mood, and even a person's smoking status.

Inspired by an earlier study that found associations between Neandertal DNA and disease risk, Janet Kelso at the Max Planck Institute for Evolutionary Anthropology in Germany says her team was interested in exploring connections between Neandertal DNA and traits unrelated to disease. In other words, they wanted to uncover the "influence Neandertal DNA might be having on ordinary variation in people today."

Because Neandertal alleles are relatively rare, the researchers needed data representing a really large number of people. They found what they were looking for in data representing more than 112,000 participants in the UK Biobank pilot study. The Biobank includes genetic data along with information on many traits related to physical appearance, diet, sun exposure, behavior, and disease.

Earlier studies had suggested that human genes involved in skin and hair biology were strongly influenced by Neandertal DNA, Kelso says. But it hadn't been clear how.

"We can now show that it is skin tone, and the ease with which one tans, as well as hair color that are affected," Kelso says.

The researchers observe multiple different Neandertal alleles contributing to skin and hair tones. What they found somewhat surprising is that some Neandertal alleles are associated with lighter skin tones and others with darker skin tones. The same was true for hair color.

"These findings suggest that Neandertals might have differed in their hair and skin tones, much as people now do" adds Michael Dannemann, first author of the study.

Kelso notes that the traits influenced by Neandertal DNA, including skin and hair pigmentation, mood, and sleeping patterns are all linked to sunlight exposure. When modern humans arrived in Eurasia about 100,000 years ago, Neandertals had already lived there for thousands of years. They were likely well adapted to lower and more variable levels of ultraviolet radiation from the sun than the new human arrivals from Africa were accustomed to.

"Skin and hair color, circadian rhythms and mood are all influenced by light exposure," the researchers wrote. "We speculate that their identification in our analysis suggests that sun exposure may have shaped Neandertal phenotypes and that gene flow into modern humans continues to contribute to variation in these traits today."

Kelso and her colleagues say they'll continue to explore Neandertals' influence on modern-day traits as more data becomes available.

New Neandertal genomes advance our understanding of human evolution


Two new studies on ancient genomes provide valuable insights into the lives of our ancestors and their cousins, the Neandertals. First, scientists have sequenced a new genome of a female Neandertal, which is only the second genome of the species to be fully sequenced with such a high level of quality. The advancement confirms a number of theories about Neandertals, but also reveals new genetic contributions of the species to modern-day humans. Neandertals are the closest evolutionary relatives of all present-day humans and therefore provide a unique perspective on human biology and history. Five Neandertal genomes have been sequenced to date, yet only one yielded high-quality data, an individual found in Siberia known as the "Altai Neandertal."

Three less well-defined genomes come from individuals found in a cave, Vindija, in Croatia, and one from Mezmaiskaya Cave, in Russia. Here, Kay Prüfer and colleagues successfully analyzed billions of DNA fragments sampled from a new individual in the Croatian cave, dubbed Vindija 33.19, a female who lived roughly 52,000 years ago. Similar to previous findings, the genetic data suggest that Neandertals lived in small and isolated populations of about 3,000 individuals.

The previously sequenced Altai Neandertal genome suggested that the individual's parents were half-siblings, prompting scientists to wonder if Neandertals commonly interbred with family members - yet the new Vindija genome does not have similar incestual patterns, suggesting that the extreme inbreeding between the parents of the Altai Neandertal may not have been ubiquitous among Neandertals. Vindija 33.19 does appear to share a maternal ancestor with two of the three other individuals from the Croatian cave who were genetically sequenced, however.

The authors use the Vindija 33.19 genome to analyze divergences and gene flow among Neandertals, Denisovans (another extinct species of hominin), and modern humans. Among many findings, they report that early modern human gene flow into Neandertal populations occurred between 130,000 and 145,000 years ago, before the Croatian and Siberian Neandertals diverged.

Based on the new high-quality genome, the authors estimate that modern non-African populations carry between 1.8-2.6% Neandertal DNA, which is higher than previous estimates of 1.5-2.1%.

Lastly, they identify a wealth of new gene variants in the Neandertal genome that are influential in modern day humans, including variants related to plasma levels of LDL cholesterol and vitamin D, eating disorders, visceral fat accumulation, rheumatoid arthritis, schizophrenia and responses to antipsychotic drugs.