(Press-News.org) CORVALLIS, Ore. – A new study of Oregon's Paisley Caves confirms that humans used the site as early as 12,450 radiocarbon years ago, and the projectile points they left behind were of the "Western Stemmed" tradition and not Clovis – which suggests parallel technological development of early inhabitants to the Americas.
The study, published this week in the journal Science, could have a major impact on theories of how the Western Hemisphere was populated. The research was funded by multiple organizations, including the National Science Foundation.
Lead author Dennis Jenkins, from the University of Oregon, and second author Loren Davis, from Oregon State University, were part of a large multidisciplinary team that spent much of the past two years combing through deposits and collecting more than 100 high-precision radiocarbon dates from Paisley Caves, located in south-central Oregon's Summer Lake basin.
What cemented the authors' findings was a thorough examination of the stratigraphy in the caves, which confirmed that coprolites containing human DNA were definitely associated with layers of sediment ranging in age from 2,295 to 12,450 years ago – and were not contaminated by humans or animals at later dates. The researchers last year also found additional Western Stemmed projectile points.
"The Western Stemmed and Clovis traditions include different technological strategies," said Davis, an associate professor of anthropology in OSU's School of Language, Culture and Society. "The Western Stemmed artifacts from Paisley Caves are at least as old – and may predate – the oldest confirmed Clovis sites, indicating that the peopling of the Americas was at least technologically divergent, if not genetically divergent."
The projectile points were found in deposits dating back to 11,070 to 11,340 radiocarbon years ago, and thus were not quite as old as the oldest coprolites. But DNA from coprolites of that era was similar to that found in the oldest coprolites, Davis pointed out. "They were from the same genetic group," he said.
The difference in technology between Clovis and Western Stemmed projectile points revolves around how they were attached to spears, which relates to the strategy of finding and shaping pieces of rock in the first place. Clovis artifacts have a distinct notch at the base, where a piece has been removed. The tool builder starts with a large rock and reduces it considerably.
Western Stemmed points and Clovis points primarily differ in the construction of their hafting portions, Davis said. Stemmed points bear constricted bases, while the hafting element of a Clovis point is thinned through the removal of a large flake from the base. Western Stemmed points are also often made by modifying smaller flakes in a different way than Clovis peoples manufactured their spear points.
"These two approaches to making projectile points were really quite different," Davis said, "and the fact that Western Stemmed point-makers fully overlap, or even pre-date Clovis point makers likely means that Clovis peoples were not the sole founding population of the Americas."
Clovis technology has only been found in the New World, while Western Stemmed technology can be related to archaeological patterns seen in northeastern Asia.
"We seem to have two different traditions co-existing in the United States that did not blend for a period of hundreds of years," said the University of Oregon's Jenkins.
Past studies of Paisley Caves also have reported on human coprolites with ancient DNA, but questions arose about whether those samples could have been contaminated, and whether they were found in context with artifacts from the same era. So the researchers did an exhaustive examination of the stratigraphy, which is one of Davis' specialties.
Davis conducted microscopic analysis of the soil structure using a petrographic microscope to eliminate signs of liquid – such as water or urine from humans or animals – moving downward through the soil. The team also carefully analyzed the silt lens where the stem points were found and bracketed above and below those layers to see if radiocarbon dates synchronized.
"The stemmed points were in great context," Davis said. "There is no doubt that they were in primary context, associated with excellent radiocarbon dates."
The earliest models for peopling of the Americas suggest that the first inhabitants arrived from Asia via a land bridge at the end of the last Ice Age and fanned out across the continent. However, those models can't explain the presence of two separate and distinct stone tool technologies at the end of the last glacial period.
"Given these recent results from Paisley Caves, it's clear that we need to come up with some better models," Davis said.
INFORMATION:
By Mark Floyd, 541-737-0788 mark.floyd@oregonstate.edu
Source: Loren Davis, 541-602-4142 loren.davis@oregonstate.edu
END
BOSTON—Scientists at Dana-Farber Cancer Institute have isolated a new type of energy-burning fat cell in adult humans which they say may have therapeutic potential for treating obesity.
Called "beige fat," the cells are found in scattered pea-sized deposits beneath the skin near the collarbone and along the spine in adult humans. Because this type of fat can burn off calories – rather than store them, as "white fat" cells do – beige fat cells might spawn new therapies for obesity and diabetes, according to researchers led by Bruce Spiegelman, PhD, of Dana-Farber.
Spiegelman ...
A clever new imaging technique discovered at the University of California, Berkeley, reveals a possible plan of attack for many bacterial diseases, such as cholera, lung infections in cystic fibrosis patients and even chronic sinusitis, that form biofilms that make them resistant to antibiotics.
By devising a new fluorescent labeling strategy and employing super-resolution light microscopy, the researchers were able to examine the structure of sticky plaques called bacterial biofilms that make these infections so tenacious. They also identified genetic targets for potential ...
What do beer, dogs and cats, and corn all have in common?
All of them are the end products of the process of domestication. Almost everybody knows that a number of different animals and plants have been bred for qualities that benefit humans. But few people realize that a number of microbes have undergone a similar transformation.
Take brewer's yeast, for example. It is the quintessential ingredient in beer making: genetically altered to convert the sugars in malted barley into alcohol and to produce metabolic byproducts that give beer its unique taste. In fact, dozens ...
Biologists at UC San Diego have discovered a chemical that offers a completely new and promising direction for the development of drugs to treat metabolic disorders such as type 2 diabetes—a major public health concern in the United States due to the current obesity epidemic.
Their discovery, detailed in a paper published July 13 in an advance online issue of the journal Science, initially came as a surprise because the chemical they isolated does not directly control glucose production in the liver, but instead affects the activity of a key protein that regulates the ...
Obesity is not to blame for poor educational performance, according to early findings from research funded by the Economic and Social Research Council (ESRC). In a study that combines statistical methods with genetic information, researchers dispel the false idea that being overweight has damaging educational consequences.
Previous studies have shown that children who are heavier are less likely to do well at school. However, Dr Stephanie von Hinke Kessler Scholder from University of York argues it's vital to understand what drives this association. "We sought to test ...
Adverse childhood experiences (ACEs) can stay with us for life. New research published in BioMed Central's open access journal Substance Abuse Treatment, Prevention, and Policy explains how these events can be tied up with adult smoking patterns, especially for women, and suggests that treatment and strategies to stop smoking need to take into account the psychological effects of childhood trauma.
ACEs can range from emotional, physical, and sexual abuse to neglect and household dysfunction and affect a large range of people. In one of the largest studies of ACEs survey ...
Receptor
The protein in question is the adenosine A2A receptor, the main receptor for caffeine in the human body. This receptor is also linked to Parkinson's disease. The class of around 800 proteins to which the adenosine A2A receptor belongs forms the target for roughly half of all medicines. 'No wonder that researchers across the globe have been trying for decades to find out more about these proteins,' comments IJzerman.
Crystallizing the protein
To find out whether medicines are effective, you need to understand how the receptors in the cell wall work. An important ...
Research: Reoperation rates after breast conserving surgery for breast cancer among women in England: retrospective study of hospital episode statistics
One in five women with breast cancer who opt for breast conserving surgery rather than a mastectomy have a reoperation, according to a national study published on bmj.com today. This information on the risk of reoperation should help women in making the decision about whether to undergo breast conserving surgery or mastectomy.
45,000 women are diagnosed with breast cancer each year in England and in 2008, 58% chose ...
Research: Impact of age and sex on primary preventative treatment for cardiovascular disease in the West Midlands, UK: cross sectional study.
More patients aged 75 and over should be prescribed drugs to help lower their risk of cardiovascular disease, a study published today on bmj.com suggests.
The researchers argue that older people are being "largely ignored" by current guidance, yet as the population ages, greater use of these drugs could reduce disability and prolong healthy life expectancy.
Cardiovascular diseases such as stroke, heart attack and heart failure ...
Diagnosis is key to the control and prevention of endemic livestock diseases in developing regions. New research has found the use of a low-cost diagnostic decision support tool could lead to the improvement in clinical practice by veterinary and animal health officers in sub-Saharan Africa.
An international team, led by Professor Mark Eisler, Chair in Global Farm Animal Health in the School of Veterinary Sciences at the University of Bristol, evaluated the effectiveness of a low-cost decision support tool as a diagnostic aid by observing whether its introduction to ...
