Dogs were domesticated at least twice, a new study suggests.

Genetic analyses of a 4,800-year-old Irish dog and 59 other ancient dogs suggest that canines and humans became pals in both Europe and East Asia long before the advent of farming, researchers report June 3 in Science. Later, dogs from East Asia accompanied their human companions to Europe, where their genetic legacy trumped that of dogs already living there, the team also concludes.

That muddled genetic legacy may help explain why previous studies have indicated that dogs were domesticated from wolves only once, although evidence hasn’t been clear about whether this took place in East Asia, Central Asia or Europe. The idea that dogs came from East Asia or Central Asia is mostly based on analysis of DNA from modern dogs, while claims for European origins have been staked on studies of prehistoric pups’ genetics. “This paper combines both types of data” to give a more complete picture of canine evolution, says Mietje Germonpré, a paleontologist at the Royal Belgian Institute of Natural Sciences in Brussels, who was not part of the study.

Understanding this domestication process may illuminate humans’ distant past — dogs were probably the first domesticated animal and may have paved the way for taming other animals and plants.

In the study, evolutionary geneticist Laurent Frantz of the University of Oxford and colleagues compiled the complete set of genes, or genome, of an ancient dog found in a tomb near Newgrange, Ireland. Researchers drilled into the hard-as-stone petrous portion of the dog’s temporal bone, which contains the inner ear, to get well-protected DNA, Frantz says.
The researchers don’t know much about what the midsize dog looked like; it doesn’t bear any genetic markers of particular modern dog breeds, Frantz says. “He wasn’t black. He wasn’t spotted. He wasn’t white.” Instead, the Newgrange dog was probably a mongrel with fur similar to a wolf’s.

But the ancient mutt has something special in his genes — a stretch of enigmatic DNA, says Germonpré. “This Irish dog has a component that can’t be found in recent dogs or recent wolves.” That distinct DNA could represent the genetic ancestry of indigenous European prehistoric dogs, she says. Or it could be a trace of an extinct ancient wolf that may have given rise to dogs (SN: 7/13/13, p. 14).
Unraveling the prehistoric mutt’s DNA may help researchers understand dogs’ history. Already, comparisons of the ancient Irish dog’s DNA with that of modern dogs reveal that East Asian dogs are genetically different from European and Middle Eastern dogs, the researchers have found. Other researchers may have missed the distinction between the two groups because they were working with subsets of the data that Frantz and colleagues amassed. Frantz’s team generated DNA data from the Newgrange dog and other ancient dogs, but also used data from previous studies of modern dogs, including the complete genomes of 80 dogs and less-complete sampling of DNA from 605 dogs, a collection of 48 breeds and village dogs of no particular breed.

The distinct genetic profiles of today’s Eastern and Western dogs suggests that two separate branches of the canine family tree once existed. The Newgrange dog’s DNA is more like that of the Western dogs. Since the Irish dog is 4,800 years old, the Eastern and Western dogs must have formed distinct groups before then, probably between about 6,400 to 14,000 years ago. The finding suggests that dogs may have been domesticated from local wolves in two separate locations during the Stone Age.

The ancient dog’s DNA may also help pinpoint when domestication happened. Using the Newgrange dog as a calibrator and the modern dogs to determine how much dogs have changed genetically in the past 4,800 years, Frantz and colleagues determined that dogs’ mutation rate is slower than researchers have previously calculated. Then, using the slower mutation rate to calculate when dogs became distinct from wolves, the researchers found that separate branches of the canine family tree formed between 20,000 and 60,000 years ago. Many previous calculations put the split between about 13,000 and about 30,000 years ago, but the new dates are consistent with figures from a study of an ancient wolf’s DNA (SN: 6/13/15, p. 10). Frantz and colleagues emphasize that their estimate doesn’t necessarily pinpoint the time of domestication. It could indicate that different populations of wolves were evolving into new species at that time. One of those could later have evolved into the ancestor of dogs.
Although the new study indicates there were two origin points for dogs, humans’ canine companions have since mixed and mingled. By comparing mitochondrial DNA, the genetic material inside energy-generating organelles, from 59 ancient European dogs and 167 modern dogs, the researchers determined that East Asian dogs at least partially genetically replaced European dogs in the distant past. Mitochondria are inherited from the mother. Ancient European dogs’ mitochondrial DNA varieties, or haplogroups, differed from those of modern dogs, the researchers found. Of the ancient dogs, 63 percent carried haplogroup C and 20 percent carried haplogroup D. But in present-day dogs, 64 percent carry haplogroup A and 22 percent carry haplogroup B. That shift and other evidence indicate that dogs from the East moved west with humans, and Eastern dogs passed more of their genetic heritage to descendants than Western dogs did.

Archaeological evidence backs up the dual origin story. Dogs as old as 12,500 years old have been found in East Asia. In Europe, dogs date back to 15,000 years ago. But there is a dearth of dog remains older than 8,000 years old in Central Eurasia. That lack possibly rules out this in-between region as a domestication site, despite some genetic evidence from village dogs that says otherwise (SN:11/28/15, p. 8). “The argument in this paper, pointing out a pattern in the archaeological data of an absence of early dog remains in the period [before] 10,000 years ago, should be taken very seriously,” says Pontus Skoglund, an evolutionary geneticist at Harvard University.

He’s not yet won over by the double-domestication hypothesis, though. The researchers admit they can’t yet rule out that dogs were domesticated once, then transported to different places where isolation, random chance and other factors caused them to drift apart genetically.

More ancient DNA may help clarify the still-hazy picture of dog domestication. Says Skoglund: “It’s going to be an exciting time going forward.”

Say hello to hobbits’ possible ancestors. Excavations of fossils from roughly 700,000-year-old hominids on the Indonesian island of Flores have reinvigorated scientific debate over the evolutionary origins and identity of Homo floresiensis, a half-sized member of the human genus — dubbed hobbits — that lived much later on Flores.

Remains of at least three individuals found at a central Flores site, called Mata Menge, probably represent early versions of H. floresiensis, says a team led by paleontologist Gerrit van den Bergh of the University of Wollongong in Australia and Japanese biological anthropologist Yousuke Kaifu. A lower-jaw fragment and six teeth excavated in 2014 come from hominids that were about as small as hobbits. These fossils look enough like hobbit jaws and teeth to be assigned provisionally to H. floresiensis, the researchers conclude in the June 9 Nature.
Researchers are divided over what the new finds imply about hobbit evolution. “Nothing related to humans on Flores has a simple explanation,” says paleoanthropologist María Martinόn-Torres of University College London. She calls the new discoveries “puzzling and exciting.”

In a second paper in Nature, archaeologist Adam Brumm of Griffith University in Nathan, Australia, and colleagues describe chemical analyses of one hominid tooth and two animal teeth, as well as of volcanic ash and sediment layers at Mata Menge, that yielded the age estimate for the finds. Excavations also uncovered 149 stone artifacts, including 47 that lay among hominid fossils, Brumm says. Nonhuman animal bones unearthed in the new dig indicate that Mata Menge hominids lived in a river valley dominated by grasslands.

Mata Menge hominids were “a dwarfed descendant of early Homo erectus that somehow got marooned on Flores,” suggests Kaifu, of the National Museum of Nature and Science in Tokyo. The Mata Menge fossils look more like H. erectus than other ancient hominids, his team reports.

H. erectus reached the Flores vicinity deep in the Stone Age, arriving on the nearby island of Java at least 1 million years ago. An unknown hominid species inhabited the Indonesian island of Sulawesi by 194,000 years ago (SN: 2/6/16, p. 7).

Hobbit fossils, previously unearthed 74 kilometers west of Mata Menge in Flores’ Liang Bua Cave, range in age from 100,000 to 60,000 years ago (SN: 4/30/16, p. 7). Stone tools probably made by hobbits date to as early as 190,000 years ago.
Stone implements previously found at Mata Menge and another Flores site date to between around 1 million and roughly 800,000 years ago (SN: 6/3/06, p. 341). The new hominid fossil finds provide the first peek at the likely makers of the Mata Menge tools, Brumm says.

Too few fossils have been found to exclude the possibility that, even if Mata Menge and Liang Bua hominids were related, they belonged to different populations that arrived on Flores at different times, Martinόn-Torres says.

Even so, the new discoveries fit a scenario in which presumably large-bodied H. erectus settled on Flores around 1 million years ago and shrank in size over the next 300,000 years, a surprisingly short time for such dramatic brain and body changes to evolve, Kaifu says. These hominids may have evolved smaller bodies over a relatively short period in response to limited island resources, proposes archaeologist Robin Dennell of the University of Sheffield in England.

But biological anthropologist William Jungers of Stony Brook University School of Medicine in New York says it’s unlikely that H. erectus shrunk to two-thirds of its initial body size and half its original brain size over only several hundred thousand years on Flores. He predicts that ongoing excavations at Mata Menge and nearby sites will uncover 1-million-year-old fossils of small-bodied hobbit ancestors that differed in many respects from H. erectus.

Like the Mata Menge team, though, Jungers says the new discoveries challenge an argument that a partial hobbit skeleton represents a Homo sapiens with Down syndrome (SN Online: 8/5/14).

Proponents of that idea disagree. Different hominids could have reached Flores at different times, as suggested by Martinόn-Torres, says Penn State developmental geneticist Robert Eckhardt. Not enough fossil evidence exists to show an evolutionary link between Mata Menge and Liang Bua individuals, Eckhardt and biological anthropologist Maciej Henneberg of the University of Adelaide in Australia argue.

The Olympic and Paralympic Games probably won’t further the international spread of Zika virus, the World Health Organization concluded in a news conference June 14.

Data from past events, including previous Olympics and World Cup tournaments, suggest that mass gatherings don’t greatly increase the spread of diseases. In addition, the 2016 Olympics will take place in August during Brazil’s winter months, when mosquito-borne diseases aren’t so rampant. Brazil also is stepping up efforts to curb mosquito populations. According to WHO, both factors are likely to reduce Zika transmission during the games.

“Everything is being done to minimize what is already a low risk,” said Bruce Aylward, who heads WHO’s division on outbreaks and health emergencies.

Not all scientists are convinced. More than 200 scientists and doctors have now signed an open letter to WHO’s director calling for postponing the Olympics and Paralympics or moving them from Rio de Janeiro.

BOSTON — Moms get blamed for a lot — including their kids’ cavities. But new data show that the most common cause of tooth decay, the bacterium Streptococcus mutans, doesn’t always come from mother-to-child transmission.

Researchers from the University of Alabama at Birmingham studied 119 children in rural Alabama and 414 of their household contacts, tracking the path of S. mutans. Contrary to expectation, 40 percent of the children did not share any strains with their mothers. Instead, those strains usually overlapped with those of siblings and cousins. And 72 percent of children carried a strain of S. mutans that no one else in the family had, probably picked up from other children at school, day care or other locations. The research was presented June 17 at ASM Microbe 2016, a meeting of the American Society for Microbiology and the Interscience Conference on Antimicrobial Agents and Chemotherapy.

While maternal transmission was still the most common route, “we’re not trying to say ‘Don’t kiss your babies,’” said Stephanie Momeni, a doctoral candidate at UAB. Rather, the ultimate goal of the research is to learn whether particular strains of S. mutans pose a greater hazard for dental health. Knowing that would help identify children who might be in need of more aggressive dental hygiene.

Driverless cars are revved up to make getting from one place to another safer and less stressful. But clashing views over how such vehicles should be programmed to deal with emergencies may stall the transportation transformation, a new study finds.

People generally approve of the idea of automated vehicles designed to swerve into walls or otherwise sacrifice their passengers to save a greater number pedestrians, say psychologist Jean-François Bonnefon of the Toulouse School of Economics in France and his colleagues. But here’s the hitch: Those same people want to ride in cars that protect passengers at all costs, even if pedestrians end up dying, the researchers report in the June 24 Science.
“Autonomous cars can revolutionize transportation,” says cognitive scientist and study coauthor Iyad Rahwan of the University of California, Irvine and MIT. “But they pose a social and moral dilemma that may delay adoption of this technology.”

Such conflict puts makers of computerized cars in a tough spot, Bonnefon’s group warns. Given a choice between driverless cars programmed for the greater good or for self-protection, consumers will overwhelmingly choose the latter. Regulations to enforce the design of passenger-sacrificing cars would backfire, the scientists suspect, driving away potential buyers. If so, plans for easing traffic congestion, reducing pollution and eliminating many traffic accidents with driverless cars would be dashed.
Further complicating matters, the investigators say, automated vehicles will need to respond to emergency situations in which an action’s consequences can’t be known for sure. Is it acceptable, for instance, to program a car to avoid a motorcycle by swerving into a wall, since the car’s passenger is more likely to survive a crash than the motorcyclist?

“Before we can put our values into machines, we have to figure out how to make our values clear and consistent,” writes Harvard University philosopher and cognitive scientist Joshua Greene in the same issue of Science.
But moral dilemmas have long dogged human civilizations and are sometimes unavoidable, says psychologist Kurt Gray of the University of North Carolina in Chapel Hill. People may endorse conflicting values depending on the situation — say, saving others when taking an impersonal perspective and saving oneself when one’s life is on the line.

Workable compromises can be reached, Gray says. If all driverless cars are programmed to protect passengers in emergencies, automobile accidents will still decline, he predicts. Despite being a danger to pedestrians on rare occasions, those vehicles “won’t speed, won’t drive drunk and won’t text while driving, which would be a win for society.”

Bonnefon’s team examined attitudes toward driverless vehicles in six online surveys conducted between June and November 2015. A total of 1,928 U.S. participants completed surveys.

Participants generally disapproved of automated vehicles sacrificing a passenger to save one pedestrian, but approval rose sharply with the number of pedestrians’ lives that could be saved. For instance, about three-quarters of volunteers in one survey said it was more moral for an automated car to sacrifice one passenger rather than kill 10 pedestrians. That trend held even when volunteers imagined they were in a driverless car with family members.

Bonnefon doubts those participants were simply trying to impress researchers with “noble” answers. But opinions changed when participants were asked about their views of driverless cars in actual practice. Responders to another survey similarly rated pedestrian-protecting automated cars as more moral, but most of those same people readily admitted that they wanted passenger-protecting cars for themselves. Other participants considered driverless cars that swerved to avoid pedestrians as good for others to drive but had little intention to buy one.

Volunteers expressed weak support for a law forcing either human drivers or automated cars to swerve to avoid pedestrians. Even in a hypothetical case where a passenger-sacrificing automated car saved the lives of 10 pedestrians, participants rated their willingness to have such sacrifices legally enforced at only 40 on a scale of 0 to 100. A final survey found that participants were much less likely to consider buying driverless cars subject to pedestrian-protecting regulations after being presented with situations in which they were riding alone, with an unspecified family member or with their child.

Fire was one of our ancient ancestors’ first forays into technology. Controlled burns enabled early hominids to ward off cold, cook and better preserve game. New evidence places fire-making in Europe as early as 800,000 years ago, much earlier than previously thought and closer to scientists’ best estimate for hominids’ first use of fire, about 1 million years ago in Africa.

It’s unclear how early Homo species came to master fire, but it was perhaps an attempt at problem solving — capturing a natural phenomenon and harnessing it for use. That tradition has persisted in human cultures. It thrives today among scientists, especially those engaged in problem solving related to society’s most pressing issues.
Take drug addiction, a vexing problem that has grown in urgency in the last decade as more and more people have become dependent on opioids — not only street drugs like heroin but also prescription pain meds like OxyContin and fentanyl. Opioids can be extremely difficult to give up because of their strong addictive pull. So scientists are trying to develop vaccines that would block the effects of heroin and other drugs of abuse, as Susan Gaidos reports. Eliciting a strong immune response, researchers theorize, could stop the drug from reaching the brain, preventing the high that fuels addiction. Success with such biotechnology, now being tested only in lab animals, would offer hope to many battling to stay off drugs.

Another modern scourge is terrorism, and anthropologists like Scott Atran have been exploring the psychological and cultural factors that drive some individuals to extreme acts of violence. There is no technology to prevent people from committing such acts — at least not yet. Basic explorations must always precede any practical use of new knowledge: Hominids could not use fire until they understood its nature and limits — which things burn, which do not; water and sand douse flame, oil and fat fuel it. Mapping terrorism’s contours is just a beginning on a long journey toward developing tactics for undercutting its power.

So it is with many other reports in this issue about basic explorations that may well precede the birth of new technologies. A few favorites:

A report on insights into how the microbial denizens of the gut influence weight gain and obesity. Scientists have now revealed a molecule made by microbes that sends a signal to the brain, influencing fat storage and appetite.

An intriguing study of mice with genetic mutations similar to those found in some people with autism. The findings suggest a role in the disorder for nerve cells involved with touch, as well as a new way to think about autism that may one day identify a target for novel therapies and interventions.

News of a second detection of gravitational waves from LIGO. It’s less dramatic and showy than the first black hole merger detection, announced in February. But it is nonetheless a further sign that a new era, one in which astronomers probe the heavens by watching for violent if subtle wakes in the fabric of spacetime, is upon us.

Feeling good may help the body fight germs, experiments on mice suggest. When activated, nerve cells that help signal reward also boost the mice’s immune systems, scientists report July 4 in Nature Medicine. The study links positive feelings to a supercharged immune system, results that may partially explain the placebo effect.

Scientists artificially dialed up the activity of nerve cells in the ventral tegmental area — a part of the brain thought to help dole out rewarding feelings. This activation had a big effect on the mice’s immune systems, Tamar Ben-Shaanan of Technion-Israel Institute of Technology in Haifa and colleagues found.

A day after the nerve cells in the ventral tegmental area were activated, mice were infected with E. coli bacteria. Later tests revealed that mice with artificially activated nerve cells had less E. coli in their bodies than mice without the nerve cell activation. Certain immune cells seemed to be ramped up, too. Monocytes and macrophages were more powerful E. coli killers after the nerve cell activation.

If a similar effect is found in people, the results may offer a biological explanation for how positive thinking can influence health.

The family of known dwarf planets orbiting the sun just got a new member. The tiny world, designated 2015 RR245, lives in the Kuiper belt, the icy debris field beyond Neptune that’s home to Pluto. RR245 is currently about 9.6 billion kilometers from the sun, or roughly 64 times as far as Earth, and it loops around the sun on an elongated orbit every 700 years or so.

Astronomers first noticed RR245 in February as a drifting speck of light in images taken last September at the Canada-France-Hawaii telescope in Hawaii. The planet’s size is hard to determine without knowing how reflective its surface is; it could be large and dark or tiny and bright. But if its surface is similar to other worlds in the Kuiper belt, then RR245 might be about 700 kilometers wide, just one-fifth the diameter of the moon.

Zika should soon run its course in Latin America.

Within the next couple of years, the epidemic that has battered the region since 2015 will largely be over, researchers estimate in a paper online July 14 in Science.

“If we’re not past the peak already, we’re very close to it,” says study coauthor Neil Ferguson of Imperial College London. After this outbreak winds down, it may be a decade ­— at least — before another large-scale Zika epidemic hits the region.
The new timeline could help vaccine researchers get a jump on future outbreaks, and might make health officials rethink advice to pregnant women trying to avoid Zika-related birth defects. Ferguson’s work also suggests something counterintuitive: Current efforts to kill Zika-carrying mosquitoes might actually make it easier for the virus to reemerge.

“It’s an important and timely analysis,” says infectious disease researcher Oliver Pybus of the University of Oxford. “Policy makers would be wise to read it carefully.”

Brazil reported the first cases of Zika in May 2015. Since then, the mosquito-borne virus has spread to 48 countries. Scientists have now widely accepted Zika as a cause of microcephaly, a devastating birth defect that leaves babies with shrunken heads and brains, as well as other serious problems (SN Online: 6/28/16).

Scientists and health officials have hustled to fight Zika, but they’ve had trouble keeping up. Mosquito-control efforts haven’t helped much, says Ferguson, and a safe and effective vaccine could still be years away. What’s more, advice to postpone pregnancy isn’t always realistic, he says.

Predicting the epidemic’s course could refine current Zika-fighting strategies.
Ferguson and colleagues made a computer simulation of Zika transmission within Latin America, using data from 35 countries that have reported cases. The team factored in such variables as seasonal climate variation, the ease with which Zika jumps from person to mosquito to person, and human travel patterns between countries.

After the current outbreak ends, simulations show that some 30 years could pass before Zika transmission picks up again. Once infected with Zika, people are immune to the virus, Ferguson says, capping an epidemic’s length and buying some time before a resurgence. He can’t say for sure that another major outbreak is still three decades away — but suspects a lull could last at least one decade.

Zika has “been burning through the population,” Ferguson says. “Sooner or later, it starts to run out of people to infect.”

The virus doesn’t need to infect everybody to peter out — just enough to generate herd immunity. At that point, so many people are immune to Zika that it can’t easily spread, protecting those still uninfected.

Killing mosquitoes — a strategy some countries have used to curb Zika’s reach — could actually hinder herd immunity, letting the next epidemic strike sooner, the team’s simulations suggest. With mosquito control that’s only marginally effective, a second wave of Zika hits about five years earlier than with no mosquito control at all, the simulations indicate.

“It makes sense theoretically,” says epidemiologist Mikkel Quam of Umeå University in Sweden. But considering that the cost of herd immunity might be more babies born with birth defects, he says, “any way to reduce infection is worth doing now, even if it means potentially more epidemics in years to come.”

Immunity to Zika could pose problems for vaccine development, Ferguson says. By the time researchers have something that’s safe to use, it will be hard to find a group of people to test it in. “This was a problem at the end of the Ebola epidemic as well,” he says.

Still, Ferguson says it’s an opportunity to think creatively. In the future, for instance, researchers could prequalify trial sites and get clinicians on the ground early, so when (and if) Zika hits somewhere else, say southeast Asia, they’re ready to go.

He also thinks his simulation could help health officials more clearly lay out the risks to pregnant women. Though the epidemic in Latin America will last roughly three years, his team estimates, individual outbreaks within the region can taper off after three to six months.

By tailoring recommendations to different locations, officials could limit the period of time they’re advising women to delay pregnancy.

When a honeybee colony gets hot and bothered, the crisis sets tongues wagging. Middle-aged bees stick their tongues into the mouths of their elders, launching these special drinker bees to go collect water. That’s just one detail uncovered during a new study of how a colony superorganism cools in hot weather.

Using lightbulbs to make heat waves in beehives, researchers have traced how honeybees communicate about collecting water and work together in deploying it as air-conditioning. The tests show just how important water is for protecting a colony from overheating, Thomas Seeley of Cornell University and his colleagues report online July 20 in the Journal of Experimental Biology.
Water collection is an aspect of bee biology that we know little about, says insect physiologist Sue Nicolson of the University of Pretoria in South Africa. Collecting pollen and nectar have gotten more attention, perhaps because honeybees store them. Water mostly gets picked up as needed.

Bees often get as much water as they need in the nectar they sip. But they do need extra water at times, such as during overheating in the center of the nest where eggs and young are coddled. When researchers artificially heated that zone in two colonies confined in a greenhouse, worker bees fought back. They used their wings to fan hot air out of the hive. “You can put your hand in the opening of a hive on a hot day and feel the blast of air that’s being pushed out,” Seeley says. Several hundred bees also moved out of the nest to cluster in a beardlike mass nearby. Their evacuation reduces body heat within the nest and opens up passageways for greater airflow, he says.

The bees also had a Plan C — evaporative cooling. Middle-aged bees inside a hive walked toward the nest entrance to where a small number of elderly bees, less than 1 percent of the colony, hang out and wait until water is needed. Heat by itself doesn’t activate these bees, especially since they’re not in the overheating core. Seeley now proposes that the burst of middle-aged bees’ repeated begging for water by tongue extension eventually sends the water-collecting bees into action. They return carrying some 80 percent of their weight in water. “The water carrier comes in looking really fat, and the water receivers start out looking very skinny,” Seeley says. “Over a minute when the transfer takes place, their forms reverse.” Then the receiving bees go to the hot zone, regurgitate their load of water and use their tongues to spread it over the fevered surfaces.

In a water-deprivation experiment, bees prevented from gathering water could not prevent temperatures from rising dangerously, up to 44° Celsius, in their hive. When researchers permitted water-collector squadrons to tank up again, colonies could control temperatures. Even for multitalented bees, water is necessary for cooling, the researchers conclude.

After a severe heat stress, the researchers noticed some bees with plumped-up abdomens hanging inside the colony. “Sometime they would be lined up like bottles of beer in the refrigerator,” Seeley says. Bottled beverages is what they were, he argues, storing water and remaining available if the coming night proved as water-stressed as the day.

“Honeybees continue to amaze,” says Dennis vanEngelsdorp of the University of Maryland in College Park, who studies bee health. “Even after centuries of study, we have something new.”