New Science/AAAS Webinar
Generating the best superresolution microscopy data: Finding the right tool for the right job
Wednesday, July 29, 2015, at 9 a.m. Pacific, 12 noon Eastern, 5 p.m. UK, 6 p.m. Central Europe
Join our roundtable discussion with microscopy experts Nobel laureate Eric Betzig, Raman Das, and Justin Taraska.
Register TODAY: webinar.sciencemag.org
Produced by the Science/AAAS Custom Publishing Office and sponsored by GE Healthcare.
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Science
Weekly News
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| A roundup of the week’s top stories in Science:
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| In Brief |
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In science news around the world, Chile and the Canary Islands are selected to share the world’s largest and most powerful gamma-ray observatory, the new Joep Lange Institute opens in Amsterdam this year to honor the HIV researcher killed in last year’s attack on a Malaysia Airlines flight, Nigeria hits an important milestone with its last known case of wild polio occurring a year ago, the five nations ringing the Arctic Ocean sign a declaration to prevent unregulated commercial fishing in its waters, and more. Also, scientists hope to limit damage done to vegetable crops by releasing genetically altered diamondback moths.
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| In Depth |
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Planetary Science
Eric Hand
On 14 July, NASA’s New Horizons spacecraft flew past Pluto, the first reconnaissance of a body in the Kuiper belt, the zone of icy objects beyond the orbit of Neptune. With the flyby complete and the data trickling home, mission scientists focused on a new challenge: making sense of an unexpectedly complex and dynamic world. Pluto contains ice mountains and smooth, crater-free plains—features suggestive of active geological processes. But mission scientists are debating whether these are the result of an atmosphere that shapes the landscape from above, or residual heat in Pluto’s interior that could be driving fresh flows of ice onto the surface.
Human Genetics
Michael Balter
Researchers still argue about how and when the first Americans settled in North and South America, and particularly about whether they came in one or multiple waves. Two new papers, one in Science and the other in Nature, attempt to shed light on this question, but they come to different conclusions: The Science team finds one wave, and the Nature team finds two. The two research groups do agree on one thing, however—some of today’s Native Americans have the genes of ancient people from Australia and Melanesia in the southwest Pacific Ocean. Knowing whether that mysterious genetic contribution came early, as the Nature team thinks, or much later, as the Science team concludes, may hold the key to remaining riddles about the peopling of the Americas.
HIV/AIDS
Jon Cohen
An 18-year-old woman in France who became infected with HIV as a baby went off antiretroviral drugs 12 years ago and the virus has yet to return to detectable levels on standard blood tests. The woman is not cured, stressed the Pasteur Institute’s Asier Sáez-Cirión, who presented details about the case at an international AIDS conference taking place in Vancouver, Canada, this week: His group found HIV DNA in her blood cells and prodded them to make new copies of the virus. Sáez-Cirión has been following a small cohort of other so-called “posttreatment controllers,” but the other all became infected with the virus as adults. He noted that the woman, like other posttreatment controllers, was distinct from the 1% of people known as elite controllers who similarly maintain undetectable plasma levels of HIV without treatment. But the elite controllers, in contrast to posttreatment controllers, keep the virus in check from the earliest days of the infection and have an immune response in many cases that explains how they thwart the virus. The hope is that this new case can help clarify how posttreatment controllers keep the virus in check and then use this information to inform both cure and vaccine research.
Nuclear Diplomacy
Richard Stone
When Iran agreed last week to dismantle large chunks of its nuclear infrastructure, it won more than the promise of relief from crippling economic sanctions. If the agreement survives strong opposition in the U.S. Congress, Iran can expect a rapid expansion of scientific cooperation with Western powers. As its nuclear facilities are repurposed, scientists from Iran and abroad will team up in areas such as nuclear fusion, astrophysics, and radioisotopes for cancer therapy. Some scientific activity will take place at the Fordow uranium enrichment facility, which Iran will convert into an international nuclear, physics, and technology center. Russia will help reconfigure 348 centrifuges there to produce stable isotopes for industry. And Fordow may host a small linear accelerator for basic research in nuclear physics and astrophysics. Iran has agreed to invite proposals for collaborative projects at Fordow and hold an international workshop to review them.
Astronomy
Daniel Clery
Are we alone in the universe? Russian internet entrepreneur Yuri Milner wants to know—and he’s willing to pay for an answer. Milner has donated $100 million for a 10-year effort to detect signals from other civilizations in the universe, an effort that has drawn high-profile support from physicists and astronomers, including Stephen Hawking. The new project, dubbed “Breakthrough Listen,” will boost funding for such searches fivefold and will be 50 times as sensitive as previous efforts and cover 10 times more of the sky. In addition, the project will throw a lifeline to budget-strapped radio telescopes, and it will develop new technology to monitor 10 billion radio frequencies simultaneously.
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| Feature |
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Elizabeth Culotta
Powered by advances in sequencing technology, the field of ancient DNA has succeeded beyond all expectations, helping researchers to retrieve the entire genomes of Neandertals and other kinds of ancient humans and transforming the picture of human evolution. Researchers have also delved into the genomes of ancient animals—the oldest so far is a 700,000-year-old horse. For years, the methods of extracting and analyzing degraded DNA molecules were so tricky that they remained the exotic province of a few high-profile labs. But now the techniques are spreading. As researchers from many fields realize just how much ancient DNA can tell them, the method is being applied to everything from the peopling of Europe to how plants and pathogens respond to climate change. The explosion of research is transforming the study of the past.
Ann Gibbons
New breakthroughs in ancient DNA are causing a revolution in the study of human evolution. By sequencing ancient DNA from the fossils of human ancestors, researchers have recently discovered new types of ancient humans and revealed interbreeding between our ancestors and our archaic cousins, including Neandertals. They are exploring how that genetic legacy is shaping our health and appearance today. And now that investigators can sequence entire ancient populations, ancient DNA is revealing that humans on every continent are a complex mix of archaic and modern DNA. Ancient DNA is enabling researchers to answer questions they could not previously address. As a result, archaeologists, anthropologists, and population geneticists are now seeking collaborations with ancient DNA researchers.
Elizabeth Pennisi
For decades, scientists have debated why the so-called megafauna disappeared from the Arctic and much of the rest of the world. Now, ancient DNA data have entered the fray. By sequencing whatever DNA emerges (called eDNA) from even a thimbleful of ancient soil, researchers are reconstructing ancient ecosystems as far back as 700,000 years ago with astonishing clarity. In 2011, they documented that a decline in the big herbivores’ favorite foods as the ice age thawed coincided with the animals’ disappearance. And a paper this week shows that local extinctions were also tied to bursts of warming. Other eDNA data—in this case from lake sediments—are illuminating how the postglacial thaw transformed other landscapes too, such as temperate forests. Finally, eDNA from Antarctic ice cores promises to reveal what happened in the Southern Hemisphere many thousands of years ago.
Elizabeth Pennisi
From muddy cliffs in Canada’s Yukon territory, where miners flush out gold-laden gravel, Beth Shapiro is netting a different sort of treasure: DNA from thousands of mammoth, bison, horse, and other mammal bones. The goal of this evolutionary biologist from the University of California, Santa Cruz, is to paint a picture of the animal community here during the past 80,000 years. Mining has exposed fossils and layers of volcanic ash, which have been dated with radiometric methods, so Shapiro can pin down the ages of fossils back to before 40,000 years ago, the limit of radiocarbon dating. And thanks to the ever-shrinking cost of sequencing, Shapiro can analyze hundreds of individuals per species to learn about important genetic changes. The project’s first papers are expected next year.
Lizzie Wade
From muddy cliffs in Canada’s Yukon territory, where miners flush out gold-laden gravel, Beth Shapiro is netting a different sort of treasure: DNA from thousands of mammoth, bison, horse, and other mammal bones. The goal of this evolutionary biologist from the University of California, Santa Cruz, is to paint a picture of the animal community here during the past 80,000 years. Mining has exposed fossils and layers of volcanic ash, which have been dated with radiometric methods, so Shapiro can pin down the ages of fossils back to before 40,000 years ago, the limit of radiocarbon dating. And thanks to the ever-shrinking cost of sequencing, Shapiro can analyze hundreds of individuals per species to learn about important genetic changes. The project’s first papers are expected next year.
Robert F. Service
Ancient DNA may be entering its golden age, but some researchers have their eyes on another molecule that may offer new view of the past: protein, which has some advantages over its more famous cousin. Tissues are full of protein, making analysis easier. Proteins also resist the ravages of time far better than fragile DNA and so have the potential to look further back in time—researchers have identified 300 million year old proteins in fish fossils. Ancient proteins have already illuminated a few far-flung corners of past life, including identifying the family tree of strange, extinct South American mammals that flummoxed even Charles Darwin. The method appears particularly promising in archaeology, where it can reveal the diets and lifestyles of past cultures. Still, the technique has a long way to go before it reaches the maturity of paleogenetics, chiefly because methods to sequence amino acids lag behind DNA sequencing.
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New Science/AAAS Webinar
Generating the best superresolution microscopy data: Finding the right tool for the right job
Wednesday, July 29, 2015, at 9 a.m. Pacific, 12 noon Eastern, 5 p.m. UK, 6 p.m. Central Europe
Join our roundtable discussion with microscopy experts Nobel laureate Eric Betzig, Raman Das, and Justin Taraska.
Register TODAY: webinar.sciencemag.org
Produced by the Science/AAAS Custom Publishing Office and sponsored by GE Healthcare.
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Science and the future 