Scientific American

Among the bloodletting boxes, ether inhalers, kangaroo-tendon sutures and other artifacts stored at the Indiana Medical History Museum in Indianapolis are hundreds of scuffed-up canning jars full of dingy yellow liquid and chunks of human brains. [More]

To monitor the biodiversity of a freshwater habitat, you could camp out by the water and count the rare wildlife. Or you could just scoop up a cup of water. A new Dutch study has found that the DNA traces in a small sample of a body of water can reveal the species that live in it. The work is in the journal Molecular Ecology . [Philip Francis Thomsen et al., " Monitoring endangered freshwater biodiversity using environmental DNA "]

Promising treatments for those blinded by an often-hereditary, retina-damaging disease are expanding throughout Europe and making their way across the pond, offering a ray of hope for the hundreds of thousands of people in the U.S. left in the dark by retinitis pigmentosa . The disease--which affects about one in 4,000 people in the U.S. and about 1.5 million people worldwide --kills the retina's photoreceptors, the rod and cone cells that convert light into electrical signals, which are transmitted via the optic nerve to the brain's visual cortex for processing. [More]

PHILADELPHIA--When you have bedbugs ( Cimex lectularius ), less interesting is the question of how they got there than the conundrum of how best to get them out. Ridding homes and businesses of these pests has become a multimillion dollar industry in many cities in the U.S. and throughout the world.

Matt is a history teacher. his twin brother, greg, is a drug addict. (Their names have been changed to protect their anonymity.) Growing up in the Boston area, both boys did well in high school: they were strong students in the classroom and decent athletes on the field, and they got along with their peers. Like many young people, the brothers snuck the occasional beer or cigarette and experimented with marijuana. Then, in college, they tried cocaine. For Greg, the experience derailed his life.

“You are what you eat.” The old adage has for decades weighed on the minds of consumers who fret over responsible food choices. Yet what if it was literally true? What if material from our food actually made its way into the innermost control centers of our cells, taking charge of fundamental gene expression?

On March 12, 1948, at 9:14 p.m. Pacific Standard Time, Northwest Airlines Flight 4422 crashed into Mount Sanford, a peak in the remote Wrangell Mountains in eastern Alaska. All 24 passengers--merchant mariners returning to the U.S. from Shanghai, China--along with six Northwest crew members, probably died on impact. The debris, too difficult to reach, was quickly covered by snow and eventually entombed by ice.

In 2009 the San Francisco police arrested Lily Haskell when she allegedly attempted to come to the aid of a companion who had already been taken into custody during a peace demonstration. The authorities released her quickly, without pressing charges. But a little piece of Haskell remained behind in their database.

Billions of years ago, organic chemicals in the primordial soup somehow organized themselves into the first organisms. A few years ago scientists found that something similar happens every once in awhile in the cells of all living things: bits of once-quiet stretches of  DNA sometimes spontaneously assemble themselves into genes. Such "de novo" genes may go on to play significant roles in the evolution of individual organisms--even humans. But how many are there?

Microbes will be the (human) food- and fuel-makers of the future, if J. Craig Venter has his way. The man responsible for one of the original sequences of the human genome as well as the team that brought you the first living cell running on human-made DNA now hopes to harness algae to make everything humanity needs. All it takes is a little genomic engineering.

"Nothing new has to be invented. We just have to combine [genes] in a way that nature has not done before. We're speeding up evolution by billions of years," Venter told an energy conference on October 18 at the New America Foundation in Washington, D.C. "It's hard to imagine a part of humanity not substantially impacted."

Escolar masquerading as white tuna. Flounder passing for Vietnamese catfish. Pricey baby cod replaced with lesser quality hake instead. Once fish is filleted and skinned, it can be difficult to distinguish, as a Boston Globe investigative report found after testing 183 pieces of fish and finding that 87 were mislabeled. This type of fraud has long vexed the seafood industry , especially for popular species such as red snapper, wild salmon and Atlantic cod, which could be mislabeled as much as 70 percent of the time. But all this fishy business could soon change.

The U.S. Food and Drug Administration, often criticized for less-than-rigorous inspection and enforcement efforts when it comes to seafood fraud, is rolling out new DNA-sequencing equipment in nine of its major laboratories across the country in a push to squelch this type of substitution. Officials say they are targeting cod, grouper, snapper, tuna and other high-value species (which are more likely to be substituted), and have already begun sequencing samples taken from retailers and wholesalers.

Anxiety around children's eating habits often peaks during sweets-laden holidays like Halloween, but the factors that contribute to excess weight in kids extend well beyond special occasions. Most children who are obese--now 17 percent in the U.S.--will carry that extra heft into adulthood, along with the long-term health consequences. Scientists project that today's generation of children will live shorter lives than their parents and have higher rates of heart disease, diabetes and atherosclerosis. Despite diverse efforts--from First Lady Michelle Obama's Let's Move campaign to the U.S. Department of Agriculture's MyPlate nutrition guidance changes--the number of overweight and obese children does not seem to be dropping, which has sent scientists searching for other drivers of the childhood obesity epidemic. [More]

Mobile DNA molecules that jump from one location in the genome to another may contribute to neurological diseases and could have subtle influences on normal brain function and behavior, according to a study published October 30 in Nature . ( Scientific American is part of Nature Publishing Group.) [More]

"Today we are learning the language with which God created life." President Bill Clinton made this remark on the White House lawn on June 2000 to recognize the decoding of the first human genome . As much as anything else, rapid DNA sequencing technology created in large part by geneticist Craig Venter and his colleagues galvanized the research community into finishing the project faster than originally expected. More than 11 years later, however, gene sequencing technology has failed to deliver on its promise to revolutionize preventative medicine, and Venter is not happy about it.

The idea was that gene sequencing would become so cheap--on the order of $1,000--that ordinary people could afford to have their individual genomes sequenced, which their family doctors would use to diagnose their predisposition for disease. Costs have fallen to about $4000, but the bigger problem is that results are often rife with errors. “If [the technology] is going to achieve the level of really impacting medicine the way I’ve always envisioned that it could, it has to become far more accurate.”

Outside Tapachula, Chiapas, Mexico--10 miles from Guatemala. To reach the cages, we follow the main highway out of town, driving past soy, cocoa, banana and lustrous dark-green mango plantations thriving in the rich volcanic soil. Past the tiny village of Rio Florido the road degenerates into an undulating dirt tract. We bump along on waves of baked mud until we reach a security checkpoint, guard at the ready. A sign posted on the barbed wire–enclosed compound pictures a mosquito flanked by a man and woman: Estos mosquitos genéticamente modificados requieren un manejo especial , it reads. We play by the rules.

In October 2009 Stanford University geneticist Anne Brunet was sitting in her office when graduate student Eric Greer came to her with a slightly heretical question. Brunet's lab had recently learned that they could lengthen a worm's lifetime by manipulating levels of an enzyme called SET2. "What if extending a worm's lifetime using SET2 can affect the life span of its descendants, even if the descendants have normal amounts of the enzyme?" he asked. [More]

In the sweltering heat of an early July afternoon, Michael R. Waters clambers down into a shadowy pit where a small hive of excavators edge their trowels into an ancient floodplain. A murmur rises from the crew, and one of the diggers gives Waters, an archaeologist at the Center for the Study of the First Americans at Texas A&M University, a dirt-smeared fragment of blue-gray stone called chert. Waters turns it over in his hand, then scrutinizes it under a magnifying loupe. The find, scarcely larger than a thumbnail, is part of an all-purpose cutting tool, an ice age equivalent of a box cutter. Tossed away long ago on this grassy Texas creek bank, it is one among thousands of artifacts here that are pushing back the history of humans in the New World and shining rare light on the earliest Americans.

Waters, a tall, rumpled man in his mid-fifties with intense blue eyes and a slow, cautious way of talking, does not look or sound like a maverick. But his work is helping to topple an enduring model for the peopling of the New World. For decades scientists thought the first Americans were Asian big-game hunters who tracked mammoths and other large prey eastward across a now submerged landmass known as Beringia that joined northern Asia to Alaska. Arriving in the Americas some 13,000 years ago, these colonists were said to have journeyed rapidly overland along an ice-free corridor that stretched from the Yukon to southern Alberta, leaving behind their distinctive stone tools across what is now the contiguous U.S. Archaeologists called these hunters the Clovis people, after a site near Clovis, N.M., where many of their tools came to light.