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Global Warming Alters Arctic Food Chain, Scientists Say, With Unforeseeable Results
New York Times, November 22, 2016

The Arctic Ocean may seem remote and forbidding, but to birds, whales and other animals, it’s a top-notch dining destination.

“It’s a great place to get food in the summertime, so animals are flying or swimming thousands of miles to get there,” said Kevin R. Arrigo, a biological oceanographer at Stanford University.

But the menu is changing. Confirming earlier research, scientists reported Wednesday that global warming is altering the ecology of the Arctic Ocean on a huge scale.

The annual production of algae, the base of the food web, increased an estimated 47 percent between 1997 and 2015, and the ocean is greening up much earlier each year.

These changes are likely to have a profound impact for animals further up the food chain, such as birds, seals, polar bears and whales. But scientists still don’t know enough about the biology of the Arctic Ocean to predict what the ecosystem will look like in decades to come.

Seeking the Gears of Our Inner Clock
New York Times, December 28, 2015

Throughout the day, a clock ticks inside our bodies. It rouses us in the morning and makes us sleepy at night. It raises and lowers our body temperature at the right times, and regulates the production of insulin and other hormones.

The body’s circadian clock even influences our thoughts and feelings. Psychologists have measured some of its effects on the brain by having people take cognitive tests at different times of day.

As it turns out, late morning turns out to be the best time to try doing tasks such as mental arithmetic that demand that we hold several pieces of information in mind at once. Later in the afternoon is the time to attempt simpler tasks, like searching for a particular letter in a page of gibberish.

Down From the Trees, Humans Finally Got a Decent Night’s Sleep
New York Times, December 17, 2015

Over the past few million years, the ancestors of modern humans became dramatically different from other primates. Our forebears began walking upright, and they lost much of their body hair; they gained precision-grip fingers and developed gigantic brains.

But early humans also may have evolved a less obvious but equally important advantage: a peculiar sleep pattern. “It’s really weird, compared to other primates,” said Dr. David R. Samson, a senior research scientist at Duke University.

In the journal Evolutionary Anthropology, Dr. Samson and Dr. Charles L. Nunn, an evolutionary biologist at Duke, reported that human sleep is exceptionally short and deep, a pattern that may have helped give rise to our powerful minds.

Fathers May Pass Down More Than Just Genes, Study Suggests
New York Times, December 3, 2015

In 2013, an obese man went to Hvidovre Hospital in Denmark to have his stomach stapled. All in all, it was ordinary bariatric surgery — with one big exception.

A week before the operation, the man provided a sperm sample to Danish scientists. A week after the procedure, he did so again. A year later, he donated a third sample.

Scientists were investigating a tantalizing but controversial hypothesis: that a man’s experiences can alter his sperm, and that those changes in turn may alter his children.

That idea runs counter to standard thinking about heredity: that parents pass down only genes to their children. People inherit genes that predispose them to obesity, or stress, or cancer — or they don’t. Whether one’s parents actually were obese or continually anxious doesn’t rewrite those genes.

A radically simple idea may open the door to a new world of antibiotics
STAT, December 3, 2015

BOSTON — Slava Epstein works in aggressively low-tech quarters at Northeastern University. You might expect otherwise, given the extraordinary work that he and his colleagues are doing, discovering new kinds of antibiotics that are fundamentally different than the ones doctors prescribe today.

And yet, when I paid Epstein a visit recently, we sat down amid a veritable landfill of scientific reprints, old Starbucks cups, and empty bottles of Vitamin Water.

“I apologize for the awful, awful mess,” he said in a light Russian accent.

Agriculture Linked to DNA Changes in Ancient Europe
New York Times, November 23, 2015

The agricultural revolution was one of the most profound events in human history, leading to the rise of modern civilization. Now, in the first study of its kind, an international team of scientists has found that after agriculture arrived in Europe 8,500 years ago, people’s DNA underwent widespread changes, altering their height, digestion, immune system and skin color.

Researchers had found indirect clues of some of these alterations by studying the genomes of living Europeans. But the new study, they said, makes it possible to see the changes as they occurred over thousands of years.

“For decades we’ve been trying to figure out what happened in the past,” said Rasmus Nielsen, a geneticist at the University of California, Berkeley, who was not involved in the new study. “And now we have a time machine.”

In a Tooth, DNA From Some Very Old Cousins, the Denisovans
New York Times, November 16, 2015

A tooth fossil discovered in a Siberian cave has yielded DNA from a vanished branch of the human tree, mysterious cousins called the Denisovans, scientists said Monday.

Their analysis pushes back the oldest known evidence for Denisovans by 60,000 years, suggesting that the species was able to thrive in harsh climates for thousands of generations. The results also suggest that the Denisovans may have bred with other ancient hominins, relatives of modern humans whom science has yet to discover.

Todd Disotell, a molecular anthropologist at New York University who was not involved in the new study, said the report added to growing evidence that our species kept company with many near relatives over the past million years. The world, Dr. Disotell said, “was a lot like Middle-earth.”

“There you’ve got elves and dwarves and hobbits and orcs,” he continued. On the real earth, “we had a ton of hominins that are closely related to us.”

After a Mass Extinction, Only the Small Survive
New York Times, November 12, 2015

From sharks to giraffes, many of Earth’s biggest and most magnificent species are threatened with extinction. A new study of the fossil record indicates that once large vertebrates disappear, evolution cannot quickly restore them — for tens of millions of years, most animals remain small.

The study, published Thursday in Science, emerged from research carried out by Lauren Sallan, a paleontologist at the University of Pennsylvania.

Studying fish that lived during the Mississippian Period, from 359 million to 323 million years ago, she noticed that they were substantially smaller than their ancestors.

“It piqued my curiosity,” Dr. Sallan said in an interview. “Why are these fish so small?” (She earned a nickname from her fellow paleontologists: the Sardine Queen.)

Inside The Drive To Collect DNA From 1 Million Veterans And Revolutionize Medicine
Stat, November 11, 2015

This is our brand new freezer,” Don Humphries said. “It holds 4 million vials.”

You’d think a freezer big enough to hold 4 million vials of blood would be easy to spot. But to my great embarrassment, I couldn’t see it.

Humphries and I were standing in a lab in the basement of the Veterans Affairs hospital in the Jamaica Plain neighborhood of Boston. He had led me through a labyrinth of windowless rooms, packed with robots handling tubes of blood donated from veterans, pipes roaring with coolant, and gorilla-sized tanks of liquid nitrogen, until he stopped next to a featureless wall.

After a few awkward moments, I admitted my ignorance. “So, where is the freezer?” I asked.

Humphries, the scientific director of the lab, blinked and then looked at the featureless wall. “Right here,” he said. He craned his head upwards. “This is it.”

I followed his gaze, and then it clicked. The wall was actually the side of a vault that seemed to be about as big as a two-story house.

Full story

Geneticist Craig Venter Helped Sequence The Human Genome. Now He Wants Yours.
Stat, November 5, 2015

If you enter Health Nucleus, a new facility in San Diego cofounded by J. Craig Venter, one of the world’s best-known living scientists, you will get a telling glimpse into the state of medical science in 2015.

Your entire genome will be sequenced with extraordinary resolution and accuracy. Your body will be scanned in fine, three-dimensional detail. Thousands of compounds in your blood will be measured. Even the microbes that live inside you will be surveyed. You will get a custom-made iPad app to navigate data about yourself. Also, your wallet will be at least $25,000 lighter.

Full story

More Than Half of Entire Species of Saigas Gone in Mysterious Die-Off
New York Times, November 2, 2015

A mysterious die-off of endangered antelopes last spring in Central Asia was even more extensive than originally thought, killing more than half of the entire species in less than a month, scientists have found.

“I’ve worked in wildlife disease all my life, and I thought I’d seen some pretty grim things,” Richard A. Kock, of the Royal Veterinary College in London, said in a telephone interview. “But this takes the biscuit.”

At a scientific meeting last week in Tashkent, Uzbekistan, Dr. Kock and his colleagues reported that they had narrowed down the possible culprits. Climate change and stormy spring weather, they said, may have transformed harmless bacteria carried by the antelopes, called saigas, into lethal pathogens.

It is a scenario that deeply worries scientists. “It’s not going to be something the species can survive,” Dr. Kock said. “If there are weather triggers that are broad enough, you could actually have extinction in one year.”

Scientists Urge National Initiative on Microbiomes
New York Times, October 28, 2015

Scores of leading scientists on Wednesday urged the creation of a major initiative to better understand the microbial communities critical to both human health and every ecosystem.

In two papers published simultaneously in the journals Science and Nature, the scientists called for a government-led effort akin to the Brain Initiative, a monumental multiyear project intended to develop new technologies to understand the human brain.

“This is the beginning of the shot to the moon,” said Jeffery F. Miller, the director of the California NanoSystems Institute at the University of California, Los Angeles, and a co-author of the Science paper. “There is so much to learn, and so many benefits of learning it.”

DNA of Ancient Children Offers Clues on How People Settled the Americas
New York Times, October 26, 2015

Researchers have long wondered how people settled the Americas, particularly the path they took to the new territory and the timing of their expansion. Until recently, archaeologists studying these questions were limited mostly to digging up skeletons and artifacts.

But now scientists have begun extracting DNA from human bones, and the findings are providing new glimpses at the history of the first Americans. On Monday, researchers at the University of Alaska and elsewhere published an important addition to the growing genetic archive.

In the Proceedings of the National Academy of Sciences, the researchers reported that they had recovered DNA from two skeletons of children who lived in Alaska 11,500 years ago. The genetic material is not only among the oldest ever found in the Americas, but also the first ancient DNA discovered in Beringia, the region around the Bering Strait where many researchers believe Asians first settled before spreading through North and South America.

In Ancient DNA, Evidence of Plague Much Earlier Than Previously Known
New York Times, October 22, 2015

Bacteria can change history.

In the 14th century, a microbe called Yersinia pestis caused an epidemic of plague known as the Black Death that killed off a third or more of the population of Europe. The long-term shortage of workers that followed helped bring about the end of feudalism.

Historians and microbiologists alike have searched for decades for the origins of plague. Until now, the first clear evidence of Yersinia pestis infection was the Plague of Justinian in the 6th century, which severely weakened the Byzantine Empire.

But in a new study, published on Thursday in the journal Cell, researchers report that the bacterium was infecting people as long as 5,000 years ago.

Exactly what those early outbreaks were like is impossible to know. But the authors of the new study suggest that plague epidemics in the Bronze Age may have opened the doors to waves of migrants in regions decimated by disease.

Editing of Pig DNA May Lead to More Organs for People
New York Times, October 15, 2015

This month, scientists gathered at the National Academy of Sciences in Washington to talk about Crispr, a new method for editing genes. In the past couple of years, the technique has become so powerful and accessible that many experts are calling for limits on its potential uses — especially altering human embryos with changes that could be inherited by future generations.

Among the scientists describing recent advances was one of Crispr’s pioneers, George Church of Harvard Medical School. In the midst of his presentation, packed with the fine details of biochemistry and genetics, Dr. Church dropped a bombshell.

In a typical experiment, scientists use Crispr to alter a single gene. But in recent work with pig cells, Dr. Church and his colleagues used Crispr to alter 62 genes at once. The researchers hope that this achievement may someday make it possible to use pig organs for transplantation into humans.

But the experiment also raises a deeper question: Could scientists someday alter complicated human traits by manipulating many genes at once?

Elephants: Large, Long-Living and Less Prone to Cancer
New York Times, October 8, 2015

In 1977, a University of Oxford statistician named Richard Peto pointed out a simple yet puzzling biological fact: We humans should have a lot more cancer than mice, but we don’t.

Dr. Peto’s argument was beguilingly simple. Every time a cell divides, there’s a small chance it will gain a mutation that speeds its growth. Cells that accumulate several of these mutations may become cancerous. The bigger an animal is, the more cells it has, and the longer an animal lives, the more times its cells divide. We humans undergo about 10,000 times as many cell divisions as mice — and thus should be far more likely to get cancer.

Yet humans and mice have roughly the same lifetime risk of cancer, a circumstance that has come to be known as Peto’s paradox.

A number of scientists have speculated that large, long-lived animals must evolve extra cancer-fighting weapons. And if that’s true, they reason, then the biggest, longest-lived animals should have an especially big arsenal. Otherwise, these species would go extinct.

Scientists Recover First Genome of Ancient Human From Africa
New York Times, October 8, 2015

A team of scientists reported on Thursday that it had recovered the genome from a 4,500-year-old human skeleton in Ethiopia — the first time a complete assemblage of DNA has been retrieved from an ancient human in Africa.

The DNA of the Ethiopian fossil is strikingly different from that of living Africans. Writing in the journal Science, the researchers conclude that people from the Near East spread into Africa 3,000 years ago. In later generations, their DNA ended up scattered across the continent.

“It’s a major milestone for the field,” said Joseph Pickrell, an expert on ancient DNA at the New York Genome Center who was not involved in the study. For decades, scientists had doubted that ancient DNA could survive in the tropics. The study raises hopes that scientists can recover far older human genomes from Africa — perhaps dating back a million years or more.

“I would bet it’s not that far in the future,” said Lee Berger, a paleoanthropologist at the University of the Witwatersrand who recently announced the discovery of an ancient humanlike species called Homo naledi.

Crows May Learn Lessons From Death
New York Times, October 1, 2015

In recent years, a peculiar sort of public performance has taken place periodically on the sidewalks of Seattle.

It begins with a woman named Kaeli N. Swift sprinkling peanuts and cheese puffs on the ground. Crows swoop in to feed on the snacks. While Ms. Swift observes the birds from a distance, notebook in hand, another person walks up to the birds, wearing a latex mask and a sign that reads “UW CROW STUDY.” In the accomplice’s hands is a taxidermied crow, presented like a tray of hors d’oeuvres.

This performance is not surreal street theater, but an experiment designed to explore a deep biological question: What do crows understand about death?

That Stinky Cheese Is a Result of Evolutionary Overdrive
New York Times, September 24, 2015

Like many biologists, Ricardo C. Rodríguez de la Vega searches the world for new species. But while other scientists venture into the depths of the ocean or the heart of the jungle, Dr. Rodríguez de la Vega and his colleagues visit cheese shops.

“Every time we’re traveling internationally for a conference or something, we go specifically to the local cheese shop and say, ‘Give me the wildest blue cheese you have,’ ” said Dr. Rodríguez de la Vega, an evolutionary biologist at the French National Centre for Scientific Research in Paris.

The cheese they buy is alive with fungi; indeed, many cheeses require a particular species of mold to properly ripen. To produce Roquefort blue cheese, for example, cheese makers mix Penicillin roqueforti into fermenting curds. The mold spreads throughout the cheese, giving it not only a distinctive blue color but also its (acquired) taste.

To produce soft cheeses such as Camembert or Brie, on the other hand, cheese makers spray a different mold species, Penicillium camemberti, on the curds. The fungus spreads its tendrils over the developing cheese, eventually forming the rind. When you chew on a Camembert rind, you’re eating a solid mat of mold.

In addition to influencing the taste, mold keeps cheese from spoiling by defending it from contaminating strains of fungi or bacteria.

Inuit Study Adds Twist to Omega-3 Fatty Acids’ Health Story
New York Times, September 17, 2015

As the Inuit people spread across the Arctic, they developed one of the most extreme diets on Earth. They didn’t farm fruits, vegetables or grains. There weren’t many wild plants to forage, aside from the occasional patch of berries on the tundra.

For the most part, the Inuit ate what they could hunt, and they mostly hunted at sea, catching whales, seals and fish. Western scientists have long been fascinated by their distinctly un-Western diet. Despite eating so much fatty meat and fish, the Inuit didn’t have a lot of heart attacks.

In the 1970s, Danish researchers studying Inuit metabolism proposed that omega-3 fatty acids found in fish were protective. Those conclusions eventually led to the recommendation that Westerners eat more fish to help prevent heart disease and sent tens of millions scrambling for fish oil pills.

Today, at least 10 percent of Americans regularly take fish oil supplements. But recent trials have failed to confirm that the pills prevent heart attacks or stroke. And now the story has an intriguing new twist.

A Pregnancy Souvenir: Cells That Are Not Your Own
New York Times, September 10, 2015

Recently, a team of pathologists at Leiden University Medical Center in the Netherlands carried out an experiment that might seem doomed to failure.

They collected tissue from 26 women who had died during or just after pregnancy. All of them had been carrying sons. The pathologists then stained the samples to check for Y chromosomes.

Essentially, the scientists were looking for male cells in female bodies. And their search was stunningly successful.

As reported last month in the journal Molecular Human Reproduction, the researchers found cells with Y-chromosomes in every tissue sample they examined. These male cells were certainly uncommon — at their most abundant, they only made up about 1 in every 1,000 cells. But male cells were present in every organ that the scientists studied: brains, hearts, kidneys and others.

In the 1990s, scientists found the first clues that cells from both sons and daughters can escape from the uterus and spread through a mother’s body. They called the phenomenon fetal microchimerism, after the chimera, a monster from Greek mythology that was part lion, goat and dragon.

Warming Oceans Putting Marine Life ‘In a Blender’
New York Times, September 3, 2015

Up in Maine, lobsters are thriving. The Atlantic States Marine Fisheries Commission reported last month that stocks there reached a record high.

Down the coast, however, the story is different. In southern New England, lobster stocks have plummeted to the lowest levels ever recorded, putting many lobstermen out of business.

Lobster populations rise and fall for many reasons. But in its new report, the commission singled out one factor that is probably driving the recent changes: The ocean is warming.

At the northern edge of the lobsters’ range, higher temperatures may be speeding up their metabolism, leading to the population boom. But at the southern edge of the range, the waters may be getting too warm, putting the animals under extreme stress.

New England’s lobsters are part of a planetwide trend. The oceans have been warming in recent decades, largely because of heat-trapping greenhouse gases humans have put in the atmosphere. Many marine species around the world have responded, moving to more comfortable waters.

The Slow Process of Countering the Emerald Ash Borer
New York Times, August 27, 2015

In 2001, ash trees began dying in Detroit, and no one could say why. Then glittering green beetles were discovered crawling out of an ash log.

American scientists had never seen the beetles, and they reached out to experts around the world for help. A Slovakian entomologist named Eduard Jendek solved the mystery: Detroit’s ash trees were being killed by Agrilus planipennis, the emerald ash borer, an obscure species native to East Asia.

In its home forests, the emerald ash borer causes little trouble. Sadly, that is not the case in North America. The emerald ash borer has spread north through Canada, south to the Gulf of Mexico, east to the Atlantic and as far west as Colorado. In a review published last year, scientists called it “the most destructive and economically costly forest insect to ever invade North America.”

Scientists are scrambling to find ways to stop the beetle. Some are testing insecticides; others are trying to quarantine healthy forests. But recent research suggests the key may be found in the trees themselves, in the chemicals they use to battle insects.

Evolving a Defense, Mimics Save Themselves
New York Times, August 20, 2015

The Canadian tiger swallowtail caterpillar is a plump green creature that spends all its time munching leaves. It ought to be an easy meal for a bird, yet many birds pass it by.

The caterpillar is protected by a remarkable defense, researchers have found: It tricks birds into thinking it’s a snake.

The caterpillar grows a pair of concentric yellow and black rings that look like a giant pair of eyes. When the caterpillar senses a bird nearby, it quickly inflates the front part of its body, making it resemble a snake’s head.

Astonishing as this deception may be, the tiger swallowtail is hardly unique. Many species have evolved ways to fool their would-be predators. Some insects look like twigs, even mimicking the way that twigs sway in the breeze.

Harmless snakes scare off predators by mimicking the look of venomous ones. Some species of hoverflies have the yellow and black stripes of stinging wasps. They even pretend to sting their enemies, despite having no stinger at all.

But mimicry has revealed a puzzle at its heart: Time and again, scientists find examples of overkill. Animals don’t seem to get an extra benefit from making their disguises more elaborate.

For Evolving Brains, a ‘Paleo’ Diet Full of Carbs
New York Times, August 13, 2015

You are what you eat, and so were your ancient ancestors. But figuring out what they actually dined on has been no easy task.

There are no Pleistocene cookbooks to consult. Instead, scientists must sift through an assortment of clues, from the chemical traces in fossilized bones to the scratch marks on prehistoric digging sticks.

Scientists have long recognized that the diets of our ancestors went through a profound shift with the addition of meat. But in the September issue of The Quarterly Review of Biology, researchers argue that another item added to the menu was just as important: carbohydrates, bane of today’s paleo diet enthusiasts.

In fact, the scientists propose, by incorporating cooked starches into their diet, our ancestors were able to fuel the evolution of our oversize brains.

Roughly seven million years ago, our ancestors split off from the apes. As far as scientists can tell, those so-called hominins ate a diet that included a lot of raw, fiber-rich plants.

For Vaccines Needed in an Epidemic, Timing is Everything
New York Times, August 6, 2015

Last year, scientists launched a trial of an experimental vaccine against Ebola in Guinea. On Friday, they reported great news: The vaccine works well, providing remarkable protection just 10 days after injection.

“We have to stop and celebrate the fact that an innovative trial design was able to come up, in the middle of an emergency, with pretty strong results,” said Dr. Seth Berkley, the chief executive officer of Gavi, an alliance of public and private organizations that provides greater access to vaccines in developing countries. “Let’s start with that.”

But let’s not end with that.

Dr. Berkley and other vaccine experts note a grim irony. Scientists showed that this vaccine was effective in monkeys a decade ago. Thereafter, the vaccine lingered in scientific limbo.

“We should have had an Ebola vaccine at least two or three years ago,” said Dr. Peter J. Hotez, the president of the Sabin Vaccine Institute and a science envoy at the State Department.

Importing Both Salamanders and Their Potential Destruction
New York Times, July 30, 2015

We humans can drive species toward extinction by hunting them or destroying their habitat. But we can also threaten them in a more subtle but no less dangerous way: by making them sick.

In the early 1900s, humans introduced malaria-spreading mosquitoes to Hawaii, and many native bird species were decimated. More recently, a fungus introduced to the United States from Europe has proved lethal to several species of bats.

Now, scientists and wildlife managers are struggling to prevent the next infectious disaster. A recently discovered fungus is killing salamanders in Europe. It is likely spread by the pet trade and could soon arrive in North America, home to about half of all salamander species.

For months, biologists have been calling for a halt to the trade in pet salamanders so they can mount a defense against the fungus. But federal officials have yet to take action.

A Social Parasite’s Sophisticated Mimicry
New York Times, July 16, 2015

An ant colony is an insect fortress: When enemies invade, soldier ants quickly detect the incursion and rip their foes apart with their oversize mandibles.

But some invaders manage to slip in with ease, none more mystifyingly than the ant nest beetle.

Adult beetles stride into an ant colony in search of a mate, without being harassed. They lay eggs, from which larva hatch. As far as scientists can tell, workers feed the young beetles as if they were ants.

When the beetles grow into adults, the ants swarm around them, grooming their bodies. In exchange for this hospitality, the beetles sink their jaws into ant larvae and freshly moulted adults in order to drink their body fluids.

“They’re like vampire beetles wandering in the ant nests,” said Andrea Di Giulio, an entomologist at Roma Tre University in Rome.

Scientists Demonstrate Animal Mind-Melds
New York Times, July 9, 2015

A single neuron can’t do much on its own, but link billions of them together into a network and you’ve got a brain.

But why stop there?

In recent years, scientists have wondered what brains could do if they were linked together into even bigger networks. Miguel A. Nicolelis, director of the Center for Neuroengineering at Duke University, and his colleagues have now made the idea a bit more tangible by linking together animal brains with electrodes.

In a pair of studies published on Thursday in the journal Scientific Reports, the researchers report that rats and monkeys can coordinate their brains to carry out such tasks as moving a simulated arm or recognizing simple patterns. In many of the trials, the networked animals performed better than individuals.

“At least some times, more brains are better than one,” said Karen S. Rommelfanger, director of the Neuroethics Program at the Center for Ethics at Emory University, who was not involved in the study.

The Cambrian Explosion’s Strange-Looking Poster Child
New York Times, July 2, 2015

The animal kingdom got off to a slow start. Studies on DNA indicate that the first animals evolved more than 750 million years ago, but for well over 200 million years, they left a meager mark on the fossil record. As best as paleontologists can tell, the animal kingdom during that time consisted of little more than sponges and other creatures rooted to the ocean floor.

But then, about 520 million years ago during the Cambrian Period, animal evolution shifted into high gear. Fast-moving predators, scavengers and burrowers evolved. Many of the major living groups of animals left their first fossils during this so-called Cambrian explosion, including our own ancestors. But the Cambrian explosion also brought many bizarre species that have long puzzled paleontologists.

For almost 40 years, the poster child for the Cambrian explosion’s strangeness has been a hand-size armored worm with a name to suit its bizarre appearance: Hallucigenia.

But recently, Hallucigenia has lost much of its mystery. Scientists have worked out the creature’s anatomy, and they have figured out a lot about how Hallucigenia and its relatives thrived in the Cambrian oceans. And despite its odd appearance, Hallucigenia isn’t an incomprehensible zoological experiment. Paleontologists have been able to place it comfortably on the evolutionary branch that led to a group of invertebrates alive today called velvet worms.

Picture This? Some Just Can’t
New York Times, June 22, 2015

Certain people, researchers have discovered, can’t summon up mental images — it’s as if their mind’s eye is blind. This month in the journal Cortex, the condition received a name: aphantasia, based on the Greek word phantasia, which Aristotle used to describe the power that presents visual imagery to our minds.

I find research like this irresistible. It coaxes me to think about ways to experience life that are radically different from my own, and it offer clues to how the mind works.

And in this instance, I played a small part in the discovery.

In 2005, a 65-year-old retired building inspector paid a visit to the neurologist Adam Zeman at the University of Exeter Medical School. After a minor surgical procedure, the man — whom Dr. Zeman and his colleagues refer to as MX — suddenly realized he could no longer conjure images in his mind.

Dr. Zeman couldn’t find any description of such a condition in medical literature. But he found MX’s case intriguing. For decades, scientists had debated how the mind’s eye works, and how much we rely on it to store memories and to make plans for the future.

New DNA Results Show Kennewick Man Was Native American
New York Times, June 18, 2015

In July 1996, two college students were wading in the shallows of the Columbia River near the town of Kennewick, Wash., when they stumbled across a human skull.

At first the police treated the case as a possible murder. But once a nearly complete skeleton emerged from the riverbed and was examined, it became clear that the bones were extremely old — 8,500 years old, it would later turn out.

The skeleton, which came to be known as Kennewick Man or the Ancient One, is one of the oldest and perhaps the most important — and controversial — ever found in North America. Native American tribes said that the bones were the remains of an ancestor and moved to reclaim them in order to provide a ritual burial.

But a group of scientists filed a lawsuit to stop them, arguing that Kennewick Man could not be linked to living Native Americans. Adding to the controversy was the claim from some scientists that Kennewick Man’s skull had unusual “Caucasoid” features. Speculation flew that Kennewick Man was European.

A California pagan group went so far as to file a lawsuit seeking to bury the skeleton in a pre-Christian Norse ceremony.

On Thursday, Danish scientists published an analysis of DNA obtained from the skeleton. Kennewick Man’s genome clearly does not belong to a European, the scientists said.

DNA Deciphers Roots of Modern Europeans
New York Times, June 10, 2015

For centuries, archaeologists have reconstructed the early history of Europe by digging up ancient settlements and examining the items that their inhabitants left behind. More recently, researchers have been scrutinizing something even more revealing than pots, chariots and swords: DNA.

On Wednesday in the journal Nature, two teams of scientists — one based at the University of Copenhagen and one based at Harvard University — presented the largest studies to date of ancient European DNA, extracted from 170 skeletons found in countries from Spain to Russia. Both studies indicate that today’s Europeans descend from three groups who moved into Europe at different stages of history.

The first were hunter-gatherers who arrived some 45,000 years ago in Europe. Then came farmers who arrived from the Near East about 8,000 years ago.

Finally, a group of nomadic sheepherders from western Russia called the Yamnaya arrived about 4,500 years ago. The authors of the new studies also suggest that the Yamnaya language may have given rise to many of the languages spoken in Europe today.

Ron Pinhasi, an archaeologist at University College Dublin who was not involved in either study, said that the new studies were “a major game-changer. To me, it marks a new phase in ancient DNA research.”

Death on the Steppes: Mystery Disease Kills Saigas
New York Times, May 29, 2015

Before the end of the last Ice Age, saigas roamed by the millions in a range stretching from England to Siberia, even into Alaska. Eventually they moved to the steppes of Central Asia, where they continued to thrive — until the 20th century, when these strange-looking antelopes began flirting with extinction.

Hunted for its horns, 95 percent of the population disappeared, and the saiga was declared critically endangered.

After the implementation of strict antipoaching measures, the population recovered, from a low of 50,000 to about 250,000 last year. “It was a big success story,” said Eleanor J. Milner-Gulland, the chairwoman of the Saiga Conservation Alliance.

Now that success is in jeopardy. Last month, a mysterious disease swept through the remaining saiga herds, littering the steppes with carcasses. The so-called die-off claimed more than a third of the world’s population in just weeks.

“I’m flustered looking for words here,” said Joel Berger, a senior scientist at the Wildlife Conservation Society. “To lose 120,000 animals in two or three weeks is a phenomenal thing.”

The Human Family Tree Bristles With New Branches
New York Times, May 27, 2015

For scientists who study human evolution, the last few months have been a whirlwind. Every couple of weeks, it seems, another team pulls back the curtain on newly discovered bones or stone tools, prompting researchers to rethink what we know about early human history.

On Wednesday, it happened again. Yohannes Haile-Selassie of the Cleveland Museum of Natural History and his colleagues reported finding a jaw in Ethiopia that belonged to an ancient human relative that lived sometime between 3.3 and 3.5 million years ago. They argue that the jaw belongs to an entirely new species, which they named Australopithecus deyiremeda.

While some experts agree, skeptics argue that the jaw belongs to a familiar hominid species, known as Australopithecus afarensis, that existed about 3.9 to 3 million years ago.

Studies like this one are adding fresh fuel to the debate over the pace of human evolution. Some researchers now believe the human family tree bore exuberant branches early on.

“I’m so excited about these discoveries I’m driving my friends crazy,” said Carol V. Ward, a paleoanthropologist at the University of Missouri. “It makes us stop and rethink everything.”

Scientists Map 5,000 New Ocean Viruses
Quanta Magazine, May 21, 2015

In March 2011, the Tara, a 36-meter schooner, sailed from Chile to Easter Island — a three-week leg of a five-year global scientific expedition. All but one of the seven scientists aboard the ship spent much of their time on the sun-drenched deck hauling up wondrous creatures such as luminous blue jellyfish and insects known as sea-skaters, which spend their entire lives skimming the surface of the ocean far from land.

At the stern of the Tara, a shipping container was bolted to the deck, with a door and a tiny window cut through the metal walls. One of the scientists, Melissa Duhaime, spent most of the voyage inside the dark, tiny cell, where she fought off an endless bout of seasickness.

“People would come in to see what I was doing and leave pretty quickly,” Duhaime said.

Inside her cell, Duhaime sat next to a hose as wide as an outstretched hand. A pump drew water through the hose from several meters below the boat and then pushed it through a series of filters. Each filter was finer than the last, blocking smaller and smaller life forms. The setup stopped animals first, then zooplankton and algae. The last filter in the hose, with pores just 220 nanometers wide, was fine enough to block bacteria. Scrubbed of all these living things, the water finally flowed into three 30-liter vats.

To the untrained eye, these vats might seem to be full of sterile water. But they were seething with ocean life — or life-like things, at the very least. The three vats held up to 1 trillion viruses.

For an Octopus, Seeing the Light Doesn’t Require Eyes
New York Times, May 20, 2015

Octopuses, squid and cuttlefish — a group of mollusks known as cephalopods — are the ocean’s champions of camouflage.

Octopuses can mimic the color and texture of a rock or a piece of coral. Squid can give their skin a glittering sheen to match the water they are swimming in. Cuttlefish will even cloak themselves in black and white squares should a devious scientist put a checkerboard in their aquarium.

Cephalopods can perform these spectacles thanks to a dense fabric of specialized cells in their skin. But before a cephalopod can take on a new disguise, it needs to perceive the background that it is going to blend into.

Cephalopods have large, powerful eyes to take in their surroundings. But two new studies in The Journal Experimental Biology suggest that they have another way to perceive light: their skin.

Reverse Engineering Birds’ Beaks Into Dinosaur Bones
New York Times, May 12, 2015

Birds evolved from dinosaurs 150 million years ago, a slow but thorough transformation. Their bodies gained aerodynamic feathers, their digits fused into wings, and they acquired a beak used to gather food.

We can see some details of this evolutionary marvel in the fossil record. Yet even the most exquisitely preserved fossil can’t tell us which pieces of DNA had to change in order to turn ground-running dinosaurs into modern birds.

Some researchers are now trying to pinpoint those genetic changes with experiments on chicken embryos. If the scientists succeed, they should eventually be able to reverse the evolution of birds — and then they may be able to engineer animals more at home in “Jurassic Park” than in a henhouse.

One group of these scientists, led by Bhart-Anjan Bhullar of Yale University and Arhat Abzhanov of Harvard University, has spent the past eight years investigating one piece of bird anatomy in particular: the beak. Now, in a study published in the journal Evolution, they report that they have found a way to turn the beaks of chicken embryos back into dinosaur-like snouts.

Under the Sea, a Missing Link in the Evolution of Complex Cells
New York Times, May 6, 2015

Unlike bacteria, humans have big, complex cells, packed with nuclei containing DNA and mitochondria that produce energy. All so-called eukaryotes share our cellular complexity: animals, plants, fungi, even single-celled protozoans like amoebae.

Scientists estimate that the first eukaryotes evolved about 2 billion years ago, in one of the greatest transitions in the history of life. But there is little evidence of this momentous event, no missing link that helps researchers trace the evolution of life from simple microbes to eukaryotes..

On Wednesday, a team of scientists announced the discovery of just such a transitional form. At the bottom of the Arctic Ocean, they found microbes that have many — but not all — of the features previously only found in eukaryotes. These microbes may show us what the progenitors of complex cellular organisms looked like.

“This is a genuine breakthrough,” said Eugene Koonin, an evolutionary biologist at the National Center for Biotechnology Information who was not involved in the research. “It’s almost too good to be true.”

Study Finds Climate Change as Threat to 1 in 6 Species
New York Times, April 30, 2015

Climate change could drive to extinction as many as one in six animal and plant species, according to a new analysis.

In a study published Thursday in the journal Science, Mark Urban, an ecologist at the University of Connecticut, also found that as the planet warms in the future, species will disappear at an accelerating rate.

“We have the choice,” he said in an interview. “The world can decide where on that curve they want the future Earth to be.”

As dire as Dr. Urban’s conclusions are, other experts said the real toll may turn out to be even worse. The number of extinctions “may well be two to three times higher,” said John J. Wiens, an evolutionary biologist at the University of Arizona.

Global warming has raised the planet’s average surface temperature about 1.5 degrees Fahrenheit since the Industrial Revolution. Species are responding by shifting their ranges.

In 2003, Camille Parmesan of the University of Texas and Gary Yohe of Wesleyan University analyzed studies of more than 1,700 plant and animal species. They found that, on average, their ranges shifted 3.8 miles per decade toward the planet’s poles.

If emissions of carbon dioxide and other greenhouse gases continue to grow, climate researchers project the world could warm by as much as 8 degrees Fahrenheit. As the climate continues to change, scientists fear, some species won’t be able to find suitable habitats.

Ancient Viruses, Once Foes, May Now Serve as Friends
New York Times, April 23, 2015

Our genomes are riddled with the detritus of ancient viruses. They infected our hominid ancestors tens of millions of years ago, inserting their genes into the DNA of their hosts.

Today, we carry about 100,000 genetic remnants of this invasion. So-called endogenous retroviruses make up 8 percent of the human genome.

Mostly, these genetic fragments are generally nothing more than molecular fossils. Over thousands of generations, they have mutated so much that they cannot replicate in our cells. And our cells keep the viral DNA muzzled to minimize the harm it might cause.

But scientists are finding that some endogenous retroviruses do wake up, and at the strangest time.

A new study published in the journal Nature on Monday suggests that endogenous retroviruses spring to life in the earliest stages of the development of human embryos. The viruses may even assist in human development by helping guide embryonic development and by defending young cells from infections by other viruses.

“The fact that viruses may be playing a vaccine role inside the cell is pretty amazing,” said Guillaume Bourque, a genomicist at McGill University who was not involved in the study.

Clues to How an Electric Treatment for Parkinson’s Works
New York Times, April 16, 2015

In 1998, Dr. Philip A. Starr started putting electrodes in people’s brains.

A neurosurgeon at the University of California, San Francisco, Dr. Starr was treating people with Parkinson’s disease, which slowly destroys essential bits of brain tissue, robbing people of control of their bodies. At first, drugs had given his patients some relief, but now they needed more help.

After the surgery, Dr. Starr closed up his patients’ skulls and switched on the electrodes, releasing a steady buzz of electric pulses in their brains. For many patients, the effect was immediate.

“We have people who, when they’re not taking their meds, can be frozen,” said Dr. Starr. “When we turn on the stimulator, they start walking.”

First developed in the early 1990s, deep brain stimulation, or D.B.S., was approved by the Food and Drug Administration for treating Parkinson’s disease in 2002. Since its invention, about 100,000 people have received implants. While D.B.S. doesn’t halt Parkinson’s, it can turn back the clock a few years for many patients.

Yet despite its clear effectiveness, scientists like Dr. Starr have struggled to understand what D.B.S. actually does to the brain.

“We do D.B.S. because it works,” said Dr. Starr, “but we don’t really know how.”

Natural Selection May Help Account for Dutch Height Advantage
New York Times, April 9, 2015

Gert Stulp stands 6 feet, 7 inches tall. His height makes him especially self-conscious at scientific conferences when he rises to describe his research as a demographer at the London School of Tropical Medicine. “It’s always quite embarrassing,” he said.

Dr. Stulp, who is Dutch, studies why his fellow citizens are so tall.

Today, the Dutch are on average the tallest people on the planet. Just 150 years ago, they were relatively short. In 1860, the average Dutch soldier in the Netherlands was just 5 feet 5 inches. American men were 2.7 inches taller.

Since 1860, average heights have increased in many parts of the world, but no people have shot up like the Dutch. The average Dutchman now stands over six feet tall. And while the growth spurt in the United States has stopped in recent years, the Dutch continue to get taller.

Why do we have allergies?
Mosaic, April 7, 2015

For me, it was hornets.

One summer afternoon when I was 12, I ran into an overgrown field near a friend’s house and kicked a hornet nest the size of a football. An angry squadron of insects clamped onto my leg; their stings felt like scorching needles. I swatted the hornets away and ran for help, but within minutes I realised something else was happening. A constellation of pink stars had appeared around the stings. The hives swelled, and new ones began appearing farther up my legs. I was having an allergic reaction.

My friend’s mother gave me antihistamines and loaded me into her van. We set out for the county hospital, my dread growing as we drove. I was vaguely aware of the horrible things that can happen when allergies run amok. I imagined the hives reaching my throat and sealing it shut.

I lived to tell the tale: my hives subsided at the hospital, leaving behind a lingering fear of hornets. But an allergy test confirmed that I was sensitive to the insects. Not to honey bees or wasps or yellow jackets. Just the particular type of hornet that had stung me. The emergency room doctor said I might not be so fortunate the next time I encountered a nest of them. She handed me an EpiPen and told me to ram the syringe into my thigh if I was stung again. The epinephrine would raise my blood pressure, open my airway – and perhaps save my life. I’ve been lucky: that afternoon was 35 years ago, and I haven’t encountered a hornet’s nest since. I lost track of that EpiPen years ago.

Behind Each Breath, an Underappreciated Muscle
New York Times, April 2, 2015

Some muscles get all the glory. Bodybuilders show off their swollen triceps; sprinters flash their sharp-edged calves. But deep inside all of us, a sheet of muscle does heroic work in obscurity.

In order to breathe in, we must flatten the dome-shaped diaphragm; to breath out, we let it relax again. The diaphragm delivers oxygen to us a dozen times or more each minute, a half-billion times during an 80-year life.

“We are completely dependent on the diaphragm,” said Gabrielle Kardon, a biologist at the University of Utah. “But we take it for granted every moment we’re breathing.”

To Dr. Kardon, the diaphragm is not just underappreciated but puzzling. All mammals, from platypuses to elephants, have a diaphragm. But no other animal has one. “We have a very different solution for breathing than reptiles and birds,” said Dr. Kardon.

Before the evolution of a diaphragm, our reptilelike ancestors probably breathed the way many reptiles do today. They used a jacket of muscles to squeeze the rib cage.

In Iceland’s DNA, New Clues to Disease-Causing Genes
New York Times, March 25, 2015

Scientists in Iceland have produced an unprecedented snapshot of a nation’s genetic makeup, discovering a host of previously unknown gene mutations that may play roles in ailments as diverse as Alzheimer’s disease, heart disease and gallstones.

“This is amazing work, there’s no question about it,” said Daniel G. MacArthur, a geneticist at Massachusetts General Hospital who was not involved in the research. “They’ve now managed to get more genetic data on a much larger chunk of the population than in any other country in the world.”

In a series of papers published on Wednesday in the journal Nature Genetics, researchers at Decode, an Icelandic genetics firm owned by Amgen, described sequencing the genomes — the complete DNA — of 2,636 Icelanders, the largest collection ever analyzed in a single human population.

With this trove of genetic information, the scientists were able to accurately infer the genomes of more than 100,000 other Icelanders, or almost a third of the entire country.

“From the technical point of view, these papers are a tour-de-force,” said David Reich, a geneticist at Harvard Medical School who was not involved in the research.

The Next Frontier: The Great Indoors
New York Times, March 19, 2015

In 1962, the ecologist Robert Whitaker set out to categorize the different realms of life on Earth. Some were deserts, others tundra, still others tropical forests. He coined a word for these inhabited environments, one that scientists have used ever since: biomes.

The planet’s biomes emerged over hundreds of millions of years. Coastal wetlands sprang up along the edges of continents about 400 million years ago. About 20 million years ago, grasslands became widespread. But the biome that we’re most familiar with — one that has a huge impact on our everyday life — is the youngest of all: the indoor biome.

When humans began building shelters about 20,000 years ago, we unrolled a welcome mat for other species. Over the past few thousand years, the indoor biome has grown to colossal proportions as cities and suburbs spread across the continents. More recently elevators and other technology have lifted the indoor biome into the sky.

If you add up the area of the indoor biome in Manhattan — including its walk-ups and high-rise apartments — it’s three times bigger than the area of the island of Manhattan itself.

An Unlikely Driver of Evolution: Arsenic
New York Times, March 12, 2015

Around 11,000 years ago, humans first set foot in the driest place on Earth.

The Atacama Desert straddles the Andes Mountains, reaching into parts of Chile, Peru, Bolivia and Argentina. Little rain falls on the desert — some spots haven’t received a single drop in recorded history.

But the people who arrived at the Atacama managed to turn it into a home. Some Atacameños, as they are known today, fished the Pacific. Others hunted game and herded livestock in the highlands. They mummified their dead, decorating them with ceremonial wigs before leaving them in the mountains.

Those mummies reveal a hidden threat in the Atacama. When scientists analyzed the hair in 7,000-year-old mummy wigs, they discovered high levels of arsenic. Through their lives, the Atacameños were gradually poisoned.

Arsenic can poison people today through exposure to pesticides and pollution. But arsenic is also naturally present in the water and soil in some parts of the world. The Atacama Desert, sitting on top of arsenic-rich volcanic rock, is one of them. The concentration of arsenic in Atacama drinking water can be 20 times higher than the level considered safe for human consumption.

Protection without a Vaccine
New York Times, March 9, 2015

Last month, a team of scientists announced what could prove to be an enormous step forward in the fight against H.I.V.

Scientists at Scripps Research Institute said they had developed an artificial antibody that, once in the blood, grabbed hold of the virus and inactivated it. The molecule can eliminate H.I.V. from infected monkeys and protect them from future infections.

But this treatment is not a vaccine, not in any ordinary sense. By delivering synthetic genes into the muscles of the monkeys, the scientists are essentially re-engineering the animals to resist disease. Researchers are testing this novel approach not just against H.I.V., but also Ebola, malaria, influenza and hepatitis.

“The sky’s the limit,” said Michael Farzan, an immunologist at Scripps and lead author of the new study.

Is Most of Our DNA Garbage?
New York Times, March 8, 2015

T. Ryan Gregory’s lab at the University of Guelph in Ontario is a sort of genomic menagerie, stocked with creatures, living and dead, waiting to have their DNA laid bare. Scorpions lurk in their terrariums. Tarantulas doze under bowls. Flash-frozen spiders and crustaceans — collected by Gregory, an evolutionary biologist, and his students on expeditions to the Arctic — lie piled in beige metal tanks of liquid nitrogen. A bank of standing freezers holds samples of mollusks, moths and beetles. The cabinets are crammed with slides splashed with the fuchsia-stained genomes of fruit bats, Siamese fighting fish and ostriches.

Gregory’s investigations into all these genomes has taught him a big lesson about life: At its most fundamental level, it’s a mess. His favorite way to demonstrate this is through what he calls the “onion test,” which involves comparing the size of an onion’s genome to that of a human. To run the test, Gregory’s graduate student Nick Jeffery brought a young onion plant to the lab from the university greenhouse. He handed me a single-edged safety razor, and then the two of us chopped up onion stems in petri dishes. An emerald ooze, weirdly luminous, filled my dish. I was so distracted by the color that I slashed my ring finger with the razor blade, but that saved me the trouble of poking myself with a syringe — I was to supply the human genome. Jeffery raised a vial, and I wiped my bleeding finger across its rim. We poured the onion juice into the vial as well and watched as the green and red combined to produce a fluid with both the tint and viscosity of maple syrup.

Two Strains of H.I.V. Cut Vastly Different Paths
New York Times, March 2, 2015

Thirty-four years ago, doctors in Los Angeles discovered that some of their patients were succumbing to a normally harmless fungus. It soon became clear that they belonged to a growing number of people whose immune systems were hobbled by a virus, eventually known as human immunodeficiency virus, or H.I.V.

To date, an estimated 78 million people have become infected, 39 million of whom have died.

As the true scale of the virus’s devastation began to emerge, a number of scientists set out to investigate its origins. Piece by piece, year after year, the scientists reconstructed its history. Their research slowly revealed that the virus did not make a single leap from animals, but several.

On Monday, a team of researchers filled in the final gaps in the history. It’s now clear, they say, that the virus originated in humans on 13 separate occasions, evolving in humans from ancestral viruses that infected monkeys, chimpanzees and gorillas.

“We’ve got an amazing amount of the story nailed down, more than any reasonable person could have expected in the 1980s,” said Michael Worobey, a professor of ecology and evolutionary biology at the University of Arizona, who was not involved in the new study.

The first clue to the evolution of H.I.V. emerged in 1985, when scientists discovered a virus in macaque monkeys that was closely related to H.I.V. As it turned out, forty African primate species harbored H.I.V.-like viruses, called simian immunodeficiency viruses, or S.I.V. It became clear that H.I.V. had evolved from an S.I.V. ancestor.

But looking for H.I.V.’s precise origins proved a difficult task.

In Short-Lived Fish, Secrets to Aging
New York Times, February 27, 2015

The turquoise killifish lives in a fleeting world: the ponds that appear only during the rainy season in East Africa.

As a new pond forms, turquoise killifish eggs buried in the mud spring from suspended animation. The eggs hatch, and in just 40 days the fish grow to full size, about 2.5 inches. They feed, mate and lay eggs. By the time the ponds dry up, the fish are all dead.

Even when hobbyists pamper them in aquariums, turquoise killifish survive only a few months, making them among the shortest-lived vertebrates on Earth. So the turquoise killifish may not seem the best animal to study to discover the secrets of a long life.

But researchers are finding that this tiny fish ages much as we do, only at a much faster pace. “It’s a compressed life span,” said Itamar Harel, a postdoctoral researcher at Stanford University. Dr. Harel and his colleagues recently developed a set of tools to probe the biology of the turquoise killifish.

Old people may seem a more logical focus for scientists looking to discover the mechanics of aging, but progress would be glacial.

“Who has 70 years to study somebody else’s aging process?” asked Sarah J. Mitchell, a postdoctoral researcher at the National Institute on Aging.

A New Theory on How Neanderthal DNA Spread in Asia
New York Times, February 19, 2015

In 2010, scientists made a startling discovery about our past: About 50,000 years ago, Neanderthals interbred with the ancestors of living Europeans and Asians.

Now two teams of researchers have come to another intriguing conclusion: Neanderthals interbred with the ancestors of Asians at a second point in history, giving them an extra infusion of Neanderthal DNA.

The findings are further evidence that our genomes contain secrets about our evolution that we might have missed by looking at fossils alone. “We’re learning new, big-picture things from the genetic data, rather than just filling in details,” said Kirk E. Lohmueller, a geneticist at the University of California, Los Angeles, and co-author of one of the new studies.

The oldest fossils of Neanderthals date back about 200,000 years, while the most recent are an estimated 40,000 years old. Researchers have found Neanderthal bones at sites across Europe and western Asia, from Spain to Siberia.

Some of those bones still retain fragments of Neanderthal DNA. Scientists have pieced those DNA fragments together, reconstructing the entire Neanderthal genome. It turns out that Neanderthals had a number of distinct genetic mutations that living humans lack. Based on these differences, scientists estimate that the Neanderthals’ ancestors diverged from ours 600,000 years ago.

Studying Oversize Brain Cells for Links to Exceptional Memory
New York Times, February 12, 2015

In 2010, a graduate student named Tamar Gefen got to know a remarkable group of older people.

They had volunteered for a study of memory at the Feinberg School of Medicine at Northwestern University. Although they were all over age 80, Ms. Gefen and her colleagues found that they scored as well on memory tests as people in their 50s. Some complained that they remembered too much.

She and her colleagues referred to them as SuperAgers. Many were also friends. “A couple tried to set me up with their grandsons,” Ms. Gefen said.

She was impressed by their resilience and humor: “It takes wisdom to a whole new level.”

Recently, Ms. Gefen’s research has taken a sharp turn. At the outset of the study, the volunteers agreed to donate their brains for medical research. Some of them have died, and it has been Ms. Gefen’s job to look for anatomical clues to their extraordinary minds.

“I had this enormous privilege I can’t even begin to describe,” she said. “I knew them and tested them in life and in death. At the end, I was the one looking at them through a microscope.”

Breakthrough DNA Editor Borne of Bacteria
Quanta Magazine, February 6, 2015

On a November evening last year, Jennifer Doudna put on a stylish black evening gown and headed to Hangar One, a building at NASA’s Ames Research Center that was constructed in 1932 to house dirigibles. Under the looming arches of the hangar, Doudna mingled with celebrities like Benedict Cumberbatch, Cameron Diaz and Jon Hamm before receiving the 2015 Breakthrough Prize in life sciences, an award sponsored by Mark Zuckerberg and other tech billionaires. Doudna, a biochemist at the University of California, Berkeley, and her collaborator, Emmanuelle Charpentier of the Helmholtz Centre for Infection Research in Germany, each received $3 million for their invention of a potentially revolutionary tool for editing DNA known as CRISPR.

Doudna was not a gray-haired emerita being celebrated for work she did back when dirigibles ruled the sky. It was only in 2012 that Doudna, Charpentier and their colleagues offered the first demonstration of CRISPR’s potential. They crafted molecules that could enter a microbe and precisely snip its DNA at a location of the researchers’ choosing. In January 2013, the scientists went one step further: They cut out a particular piece of DNA in human cells and replaced it with another one.

In the same month, separate teams of scientists at Harvard University and the Broad Institute reported similar success with the gene-editing tool. A scientific stampede commenced, and in just the past two years, researchers have performed hundreds of experiments on CRISPR. Their results hint that the technique may fundamentally change both medicine and agriculture.

In Bedbugs, Scientists See a Model of Evolution
New York Times, February 5, 2015

In the closing sentence of “The Origin of Species,” Charles Darwin marvels at the process of evolution, observing how “from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”

Few people would describe bedbugs as most beautiful or most wonderful. Yet this blood-feeding pest may represent an exceptional chance to observe the emergence of Darwin’s “endless forms”: New research indicates that some bedbugs are well on their way to becoming a new species.

“For something that is so hated by so many people, it might just be a perfect model organism for evolutionary questions,” said Warren Booth, a biologist at the University of Tulsa and a co-author of the new study, published in Molecular Ecology.

Scientists have been very slow to appreciate the biology of bedbugs despite the fact that the insects have infiltrated human shelters for thousands of years. That’s because the insects practically vanished at the dawn of modern biology in the 1940s, thanks to the widespread use of DDT.

Bedbugs have returned with a vengeance in recent years, partly because they have evolved resistance to pesticides, and scientists are struggling to learn more about these pests. It’s a much bigger challenge than examining, say, monarch butterflies.

In the Way Cancer Cells Work Together, a Possible Tool for Their Demise
New York Times, January 29, 2015

A tumor, as strange as it may sound, is a little society. The cancer cells that make it up cooperate with one another, and together they thrive.

Scientists are only starting to decipher the rules of these communities. But if they can understand how these cells work together, then they may be able to stop the tumor. “You can drive it to collapse,” said Marco Archetti, a biologist at the University of East Anglia and at the Icahn School of Medicine at Mount Sinai.

Cancer starts when healthy cells mutate and lose the safeguards that normally keep their growth in check. The cells start to multiply quickly, and their descendants gain new mutations, some of which make the cells even better at multiplying.

As tumors rapidly develop, they outgrow their blood supply, and stores of nutrients and growth-stimulating chemicals, known as growth factors, run low. As it turns out, cancer cells survive this harsh new environment by helping one another.

New mutations can cause cancer cells to start making their own growth factors, and they don’t keep these essential chemicals to themselves. Growth factors seep throughout the tumor, affecting all the cells. “It’s one of the hallmarks of cancer,” Dr. Archetti said.

Even Elusive Animals Leave DNA, and Clues, Behind
New York Times, January 22, 2015

You wouldn’t think hellbenders would be hard to find: The huge salamanders, the biggest amphibians in North America, can grow up to 30 inches long. Yet hellbenders make themselves scarce, living on the bottoms of mountain streams, lurking under massive rocks.

As a result, locating hellbenders takes a crew of scientists. First, some of them must wedge a long pole under a rock to hoist it up, and then their colleagues must plunge into the chilly water to catch their quarry.

A couple of years ago, Stephen Spear, a conservation scientist at the Orianne Society in Athens, Ga., heard about a possible alternative. Instead of finding rare animals, some experts were gathering animal DNA from their habitats. That way, they didn’t have to track down a species to be sure it was there.

Dr. Spear decided to try. He traveled to rivers in the Southeast where he and his colleagues had found hellbenders, and scooped water into jugs.

Raising Alarm, Study Finds Oceans on Brink of Wave of Extinctions
New York Times, January 15, 2015

A team of scientists, in a groundbreaking analysis of data from hundreds of sources, has concluded that humans are on the verge of committing unprecedented damage to the oceans and the animals living in them.

“We may be sitting on a precipice of a major extinction event,” said Douglas J. McCauley, an ecologist at the University of California, Santa Barbara, and a co-author of the new research, which was published on Thursday in the journal Science.

But there is still time to avert catastrophe, Dr. McCauley and his colleagues also found. Compared with the continents, the oceans are mostly intact, still wild enough to bounce back to ecological health.

“We’re lucky in many ways,” said Malin L. Pinsky, a marine biologist at Rutgers University and a co-author of the new report. “The impacts are accelerating, but they’re not so bad we can’t reverse them.”

Unraveling the Key to a Cold Virus’s Effectiveness
New York Times, January 8, 2015

If there is a champion among contagions, it may well be the lowly rhinovirus, responsible for many of the coughs and sniffles that trouble us this time of year. Rhinoviruses are spectacularly effective at infecting humans. Americans suffer one billion colds a year, and rhinoviruses are the leading cause of these infections.

Scientists have never been sure why they are so effective, but now a team at Yale University may have found a clue. The scientists argue that rhinoviruses have found a blind spot in the human immune system: They take advantage of the cold air in our noses.

In the 1960s, researchers first noticed that if they incubated rhinoviruses a few degrees below body temperature, the viruses multiplied much faster. It was an intriguing finding, since rhinoviruses often infect the lining of the nostrils, which are cooled by incoming air.

In subsequent years, scientists searched for an explanation. “People have taken the virus apart and studied its parts,” said Akiko Iwasaki, an immunobiologist at Yale. “But none of this really added up to explain why the virus replicated faster at a lower temperature.”

Can Hermaphrodites Teach Us What It Means To Be Male?
This View of Life, January 4, 2015

The vinegar worm (officially known as Caenorhabditis elegans) is about as simple as an animal can be. When this soil-dwelling nematode reaches its adult size, it measures a millimeter from its blind head to its tapered tail. It contains only a thousand cells in its entire body. Your body, by contrast, is made of 36 trillion cells. Yet the vinegar worm divides up its few cells into the various parts you can find in other animals like us, from muscles to a nervous system to a gut to sex organs.

In the early 1960s, a scientist named Sydney Brenner fell in love with the vinegar worm’s simplicity. He had decided to embark on a major study of humans and other animals. He wanted to know how our complex bodies develop from a single cell. He was also curious as to how neurons wired into nervous systems that could perceive the outside world and produce quick responses to keep animals alive. Scientists had studied these two questions for decades, but they still knew next to nothing about the molecules involved. When Brenner became acquainted with the vinegar worm in the scientific literature, he realized it could help scientists find some answers.

Its simplicity was what made it so enticing. Under a microscope, scientists could make out every single cell in the worm’s transparent body. It would breed contentedly in a lab, requiring nothing but bacteria to feed on. Scientists could search for mutant worms that behaved in strange ways, and study them to gain clues to how their mutations to certain genes steered them awry.

A Weakness in Bacteria’s Fortress
Scientific American, January 2015

At the University of Zurich, Rolf Kümmerli investigates new drugs to stop deadly infections. He spends his days in a laboratory stocked with petri dishes and flasks of bacteria—exactly the place where you would expect him to do that sort of work. But Kümmerli took an odd path to get to that lab. As a graduate student, he spent years hiking through the Swiss Alps to study the social life of ants. Only after he earned a Ph.D. in evolutionary biology did he turn his attention to microbes.

The path from ants to antibiotics is not as roundabout as it may seem. For decades scientists have studied how cooperative behavior evolves in animal societies such as ant colonies, in which sterile female workers raise the eggs of their queen. A new branch of science—sometimes called “sociomicrobiology”—is revealing that some of the same principles that govern ants can explain the emergence of bacterial societies. Like ants, microbes live in complex communities, where they communicate with one another to cooperate for the greater good. This insight of social evolution suggests a new strategy for stopping infections: instead of attacking individual bacteria, as traditional antibiotics do, scientists are exploring the notion of attacking entire bacterial societies.

New strategies are exactly what is needed now. Bacteria have evolved widespread resistance to antibiotics, leaving doctors in a crisis. For example, the Centers for Disease Control and Prevention estimates that 23,000 people die in the U.S. every year of antibiotic-resistant infections. Strains of tuberculosis and other pathogens are emerging that are resistant to nearly every drug. “It already is a substantial problem,” says Anthony S. Fauci, director of the National Institute of Allergy and Infectious Disease. “And there's every reason to believe it's going to get even worse.”

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