Friday, October 30, 2009
Pairing a new approach to prepare ancient DNA with a new scientific technique developed specifically to genotype a cow, an MU animal scientist, along with a team of international researchers, created a very accurate and widespread "family tree" for cows and other ruminants, going back as far as 29 million years.
This genetic information could allow scientists to understand the evolution of cattle, ruminants and other animals. This same technique also could be used to verify ancient relatives to humans, help farmers develop healthier and more efficient cattle, and assist scientists who are studying human diseases, according to the research, which is being published in the Proceedings of the National Academy of Sciences (PNAS).
"We studied 678 different animals, representing 61 different species, and using the new Illumina cow 'SNP chip,' or 'snip chip,' we were able to generate some very precise genetic data for which the chip was not designed," said Jerry Taylor, a professor of animal science in the MU College of Agriculture, Food and Natural Resource and lead author of the study. "Our SNP chips allow scientists to examine hundreds of thousands of points on an animal's genome simultaneously. When we applied this technique to 48 recognized breeds of cattle, we were able to construct a family tree and infer the history of cattle domestication and breed formation across the globe."
The research revealed the history of European cattle, with domesticated cattle moving sequentially through Turkey, the Balkans and Italy, then spreading through Central Europe and France, and ending in Britain. The scientists also found evidence supporting a second route of ancient cattle into Europe by way of the Iberian Peninsula.
The applications for this technology and information discovered in the research could help solve a number of problems and answer questions about evolution, including how humans are related to extinct hominids and how different plant species are related to each other, Taylor said.
Based on the findings, animal scientists can begin to study evolution of certain breeds. For example, if breeds of cattle with high amounts of intramuscular fat, which is known as marbling, are closely related to each other, then they likely share the same gene variations to create the marbling, which is a trait some beef consumers prefer. On the other hand, if those same cattle are not closely related, different genetic variants might be at work. Understanding how different genetic variations allow high levels of marbling, feed efficiency and disease resistance in cattle could have a large economic impact for farmers who raise cattle throughout the world.
"This also provides us an opportunity to identify animal models for human disease since, for example, an excess amount of intramuscular fat in humans is associated with insulin resistance and type 2 diabetes," Taylor said. We're all interested in reconstructing our ancestry. This is essentially the same thing, except that we're able to zoom out by millions of years and include relatives who are long gone. The amazing thing about this technique is that it is very fast and extremely cheap. For relatively small amounts of money, we can generate the data that will allow us to recreate millions of years of evolutionary history."
(Photo: U. Missouri)
University of Missouri
It started in the year 1000 BCE, when the Jebusite city's water system proved to be its undoing. The Spring of Gihon sat just outside the city walls, a vital resource in the otherwise parched region. But King David, in tent on taking the city, sent an elite group of his soldiers into a karst limestone tunnel that fed the spring. His men climbed up through a cave system hollowed out by flowing water, infiltrated beneath the city walls, and attacked from the inside. David made the city the capital of his new kingdom, and Israel was born.
In a new analysis of historical documents and detailed geological maps, Michael Bramnik of Northern Illinois University added new geological accents to this pivotal moment in human history in a presentation Tuesday, October 20 at the annual meeting of the Geological Society of America in Portland.
"The karst geology played a major role in the city's selection by David for his capital," Bramnik said.
It proved to be a wise decision. One of David's successors, King Hezekiah watched as the warlike Assyrian horde, a group of vastly superior warriors toppled city after city in the region. Fearing that they'd soon come for Jerusalem, he too took advantage of the limestone bedrock and dug a 550 meter-long (1804 feet) tunnel that rerouted the spring's water inside the city's fortified walls.
The Assyrians laid siege to the city in 701 BCE, but failed to conquer it. It was the only city in history to successfully fend them off.
"Surviving the Assyrian siege put it into the people's minds that it was because of their faith that they survived," Bramnik said. "So when they were captured by the Babylonians in 587, they felt it was because their faith had faltered."
Until then, the Jewish religion had been loosely associated. But that conviction united the Jews through the Babylonian Captivity, "and so began modern congregational religion," Bramnik said.
In an arid region rife with conflict, water security is as important today as it was during biblical times. While the groundwater for Jerusalem is recharged surface waters in central Israel, other settlements' water sources are not publicly available for research. Bramnik's efforts to find detailed hydrological maps were often rebuffed, or the maps were said to be non-existent.
"I think Jerusalem's geology and the geology of Israel is still significant to life in the region, perhaps even reaching into the political arena," he said.
The Geological Society of America
"There is this idea that because medicine has been so good at reducing mortality rates, that means that natural selection is no longer operating in humans," said Stephen Stearns of Yale University. A recent analysis by Stearns and colleagues turns this idea on its head. As part of a working group sponsored by the National Evolutionary Synthesis Center in Durham, NC, the team of researchers decided to find out if natural selection — a major driving force of evolution — is still at work in humans today. The result? Human evolution hasn't ground to a halt. In fact, we're likely to evolve at roughly the same rates as other living things, findings suggest.
Taking advantage of data collected as part of a 60-year study of more than 2000 North American women in the Framingham Heart Study, the researchers analyzed a handful of traits important to human health. By measuring the effects of these traits on the number of children the women had over their lifetime, the researchers were able to estimate the strength of selection and make short-term predictions about how each trait might evolve in the future. After adjusting for factors such as education and smoking, their models predict that the descendents of these women will be slightly shorter and heavier, will have lower blood pressure and cholesterol, will have their first child at a younger age, and will reach menopause later in life.
"The take-home message is that humans are currently evolving," said Stearns. "Natural selection is still operating."
The changes may be slow and gradual, but the predicted rates of change are no different from those observed elsewhere in nature, the researchers say. "The evolution that's going on in the Framingham women is like average rates of evolution measured in other plants and animals," said Stearns. "These results place humans in the medium-to-slow end of the range of rates observed for other living things," he added. "But what that means is that humans aren't special with respect to how fast they're evolving. They're kind of average."
National Evolutionary Synthesis Center
Most of the technology needed to shift the world from fossil fuel to clean, renewable energy already exists. Implementing that technology requires overcoming obstacles in planning and politics, but doing so could result in a 30 percent decrease in global power demand, say Stanford civil and environmental engineering Professor Mark Z. Jacobson and University of California-Davis researcher Mark Delucchi.
To make clear the extent of those hurdles – and how they could be overcome – they have written an article that is the cover story in the November issue of Scientific American. In it, they present new research mapping out and evaluating a quantitative plan for powering the entire world on wind, water and solar energy, including an assessment of the materials needed and costs. And it will ultimately be cheaper than sticking with fossil fuel or going nuclear, they say.
The key is turning to wind, water and solar energy to generate electrical power – making a massive commitment to them – and eliminating combustion as a way to generate power for vehicles as well as for normal electricity use.
The problem lies in the use of fossil fuels and biomass combustion, which are notoriously inefficient at producing usable energy. For example, when gasoline is used to power a vehicle, at least 80 percent of the energy produced is wasted as heat.
With vehicles that run on electricity, it's the opposite. Roughly 80 percent of the energy supplied to the vehicle is converted into motion, with only 20 percent lost as heat. Other combustion devices can similarly be replaced with electricity or with hydrogen produced by electricity.
Jacobson and Delucchi used data from the U.S. Energy Information Administration to project that if the world's current mix of energy sources is maintained, global energy demand at any given moment in 2030 would be 16.9 terawatts, or 16.9 million megawatts.
They then calculated that if no combustion of fossil fuel or biomass were used to generate energy, and virtually everything was powered by electricity – either for direct use or hydrogen production – the demand would be only 11.5 terawatts. That's only two-thirds of the energy that would be needed if fossil fuels were still in the mix.
In order to convert to wind, water and solar, the world would have to build wind turbines; solar photovoltaic and concentrated solar arrays; and geothermal, tidal, wave and hydroelectric power sources to generate the electricity, as well as transmission lines to carry it to the users, but the long-run net savings would more than equal the costs, according to Jacobson and Delucchi's analysis.
"If you make this transition to renewables and electricity, then you eliminate the need for 13,000 new or existing coal plants," Jacobson said. "Just by changing our infrastructure we have less power demand."
Jacobson and Delucchi chose to use wind, water and solar energy options based on a quantitative evaluation Jacobson did last year of about a dozen of the different alternative energy options that were getting the most attention in public and political discussions and in the media. He compared their potential for producing energy, how secure an energy source each was, and their impacts on human health and the environment.
He determined that the best overall energy sources were wind, water and solar options. His results were published in Energy and Environmental Science.
The Scientific American article provides a quantification of global solar and wind resources based on new research by Jacobson and Delucchi.
Analyzing only on-land locations with a high potential for producing power, they found that even if wind were the only method used to generate power, the potential for wind energy production is 5 to 15 times greater than what is needed to power the entire world. For solar energy, the comparable calculation found that solar could produce about 30 times the amount needed.
If the world built just enough wind and solar installations to meet the projected demand for the scenario outlined in the article, an area smaller than the borough of Manhattan would be sufficient for the wind turbines themselves. Allowing for the required amount of space between the turbines boosts the needed acreage up to 1 percent of Earth's land area, but the spaces between could be used for crops or grazing. The various non-rooftop solar power installations would need about a third of 1 percent of the world's land, so altogether about 1.3 percent of the land surface would suffice.
The study further provides examples of how a combination of renewable energy sources could be used to meet hour-by-hour power demand, addressing the commonly asked question, given the inherent variability of wind speed and sunshine, can these sources consistently produce enough power? The answer is yes.
Expanding the transmission grid would be critical for the shift to the sustainable energy sources that Jacobson and Delucchi propose. New transmission lines would have to be laid to carry power from new wind farms and solar power plants to users, and more transmission lines will be needed to handle the overall increase in the quantity of electric power being generated.
The researchers also determined that the availability of certain materials that are needed for some of the current technologies, such as lithium for lithium-ion batteries, or platinum for fuel cells, are not currently barriers to building a large-scale renewable infrastructure. But efforts will be needed to ensure that such materials are recycled and potential alternative materials are explored.
Finally, they conclude that perhaps the most significant barrier to the implementation of their plan is the competing energy industries that currently dominate political lobbying for available financial resources. But the technologies being promoted by the dominant energy industries are not renewable and even the cleanest of them emit significantly more carbon and air pollution than wind, water and sun resources, say Jacobson and Delucchi.
If the world allows carbon- and air pollution-emitting energy sources to play a substantial role in the future energy mix, Jacobson said, global temperatures and health problems will only continue to increase.
(Photo: Stanford U.)
You can teach an old dog new tricks, say UCLA scientists who found that middle-aged and older adults with little Internet experience were able to trigger key centers in the brain that control decision-making and complex reasoning after just one week of surfing the Web.
The findings, presented Oct. 19 at the 2009 meeting of the Society for Neuroscience, suggest that Internet training can stimulate neural activation patterns and could potentially enhance brain function and cognition in older adults.
As the brain ages, a number of structural and functional changes occur, including atrophy, reductions in cell activity and increases in deposits of amyloid plaques and tau tangles, which can impact cognitive function.
Research has shown that mental stimulation similar to that which occurs in individuals who frequently use the Internet may affect the efficiency of cognitive processing and alter the way the brain encodes new information.
"We found that for older people with minimal experience, performing Internet searches for even a relatively short period of time can change brain activity patterns and enhance function," said study author Dr. Gary Small, a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA and the author of "iBrain," a book that describes the impact of new technology on the brain and behavior.
The UCLA team worked with 24 neurologically normal volunteers between the ages of 55 and 78. Prior to the study, half the participants used the Internet daily, while the other half had very little experience. Age, educational level and gender were similar between the two groups.
Study participants performed Web searches while undergoing functional magnetic resonance imaging (fMRI) scans, which recorded the subtle brain-circuitry changes experienced during this activity. This type of scan tracks brain activity by measuring the level of cerebral blood flow during cognitive tasks.
After the initial brain scan, participants went home and conducted Internet searches for one hour a day for a total of seven days over a two-week period. These practice searches involved using the Internet to answer questions about various topics by exploring different websites and reading information. Participants then received a second brain scan using the same Internet simulation task but with different topics.
The first scan of participants with little Internet experience demonstrated brain activity in regions controlling language, reading, memory and visual abilities, which are located in the frontal, temporal, parietal, visual and posterior cingulate regions, researchers said. The second brain scan of these participants, conducted after the practice Internet searches at home, demonstrated activation of these same regions, as well as triggering of the middle frontal gyrus and inferior frontal gyrus – areas of the brain known to be important in working memory and decision-making.
Thus, after Internet training at home, participants with minimal online experience displayed brain activation patterns very similar to those seen in the group of savvy Internet users – after just a brief period of time.
"The results suggest that searching online may be a simple form of brain exercise that might be employed to enhance cognition in older adults," said Teena D. Moody, the study's first author and a senior research associate at the Semel Institute at UCLA.
When performing an Internet search, the ability to hold important information in working memory and to extract the important points from competing graphics and words is essential, Moody noted.
Previous research by the UCLA team found that searching online resulted in a more than twofold increase in brain activation in older adults with prior experience, compared with those with little Internet experience. According to Small, the new findings suggest that it may take only days for those with minimal experience to match the activity levels of those with years of experience.
Additional studies may address the impact of the Internet on younger individuals and help identify aspects of online searching that generate the greatest levels of brain activation.
Archaeologists surveying the world’s oldest submerged town have found ceramics dating back to the Final Neolithic. Their discovery suggests that Pavlopetri, off the southern Laconia coast of Greece, was occupied some 5,000 years ago — at least 1,200 years earlier than originally thought.
These remarkable findings have been made public by the Greek government after the start of a five year collaborative project involving the Ephorate of Underwater Antiquities of the Hellenic Ministry of Culture and The University of Nottingham.
As a Mycenaean town the site offers potential new insights into the workings of Mycenaean society. Pavlopetri has added importance as it was a maritime settlement from which the inhabitants coordinated local and long distance trade.
The Pavlopetri Underwater Archaeology Project aims to establish exactly when the site was occupied, what it was used for and through a systematic study of the geomorphology of the area, how the town became submerged.
This summer the team carried out a detailed digital underwater survey and study of the structural remains, which until this year were thought to belong to the Mycenaean period — around 1600 to 1000 BC. The survey surpassed all their expectations. Their investigations revealed another 9,000 square metres of new buildings as well as ceramics that suggest the site was occupied throughout the Bronze Age — from at least 2800 BC to 1100 BC.
The work is being carried out by a multidisciplinary team led by Mr Elias Spondylis, Ephorate of Underwater Antiquities of the Hellenic Ministry of Culture in Greece and Dr Jon Henderson, an underwater archaeologist from the Department of Archaeology at The University of Nottingham.
Dr Jon Henderson said: “This site is unique in that we have almost the complete town plan, the main streets and domestic buildings, courtyards, rock-cut tombs and what appear to be religious buildings, clearly visible on the seabed. Equally as a harbour settlement, the study of the archaeological material we have recovered will be extremely important in terms of revealing how maritime trade was conducted and managed in the Bronze Age.”
Possibly one of the most important discoveries has been the identification of what could be a megaron — a large rectangular great hall — from the Early Bronze Age period. They have also found over 9,000 square metres of new buildings including what could be the first example of a pillar crypt ever discovered on the Greek mainland. Two new stone built cist graves were also discovered alongside what appears to be a Middle Bronze Age pithos burial.
Mr Spondylis said: “It is a rare find and it is significant because as a submerged site it was never re-occupied and therefore represents a frozen moment of the past.”
The Archaeological Co-ordinator Dr Chrysanthi Gallou a postdoctoral research fellow at The University of Nottingham is an expert in Aegean Prehistory and the archaeology of Laconia.
Dr Gallou said: “The new ceramic finds form a complete and exceptional corpus of pottery covering all sub-phases from the Final Neolithic period (mid 4th millennium BC) to the end of the Late Bronze Age (1100 BC). In addition, the interest from the local community in Laconia has been fantastic. The investigation at Pavlopetri offers a great opportunity for them to be actively involved in the preservation and management of the site, and subsequently for the cultural and touristic development of the wider region.”
The team was joined by Dr Nicholas Flemming, a marine geo-archaeologist from the Institute of Oceanography at the University of Southampton, who discovered the site in 1967 and returned the following year with a team from Cambridge University to carry out the first ever survey of the submerged town. Using just snorkels and tape measures they produced a detail plan of the prehistoric town which consisted of at least 15 separate buildings, courtyards, streets, two chamber tombs and at least 37 cist graves. Despite the potential international importance of Pavlopetri no further work was carried out at the site until this year.
This year, through a British School of Archaeology in Athens permit, The Pavlopetri Underwater Archaeology Project began its five year study of the site with the aim of defining the history and development of Pavlopetri.
Four more fieldwork seasons are planned before their research is published in full in 2014.
(Photo: U. Nottingham)