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A Little Perspective: The Amish iPhone and a butterfly's engineered wing color

A young woman, wearing a traditional full-length Amish dress and white bonnet, steps away from a farmers' market in Manheim, Pa., opens her palm and reveals a smartphone. She begins to scroll through screens, seemingly oblivious to the activity around her. The Amish have not given up on horse-drawn buggies. Their rigid abstinence from many kinds of technology has left parts of their lifestyle frozen since the 19th century: no cars, TVs or connections to electric utilities, for example. But computers and cellphones are making their way into some Amish communities, pushing them — sometimes willingly, often not — into the 21st century.

For people bound by a separation from much of the outside world, new tech devices have brought fears about the consequence of Internet access. "Amish life is about recognizing the value of agreed-upon limits," said Erik Wesner, an author who runs a blog, Amish America, "and the spirit of the Internet cuts against the idea of limits."

Many Amish people draw a bright line between what is allowed at work — smartphones, Internet access — and what remains forbidden at home. Still, the divisions can get fuzzy. Connecting a house to the public utility is unheard-of, but many homes are electrified with power generators and solar panels. Propane-powered refrigerators are found in many kitchens. And "Amish taxi" services, driven by non-Amish people, provide a way to get around without violating the rule against owning a car.

John, who like many Amish gives only his first name out of humility, has worries about where technology is taking the Amish community. "We're not supposed to have computers; we're not supposed to have cellphones," he said. "We're allowed to have a phone, but not in the house. But to do business, you need a computer, or access to one, and that phone moves into the house. So how do you balance that?"

Kevin Granville and Ashley Gilbertson, New York Times

Only nature can paint the gorgeous colors and patterns on a butterfly's wings. But scientists say they have mastered the first steps and hope in time to control the entire coloring system, making it possible to design living butterfly wings. The patterning and colors on butterflies' wings are governed by suites of genes. The new Crispr-Cas gene-editing technique now makes it much easier to figure out what a gene does by deleting it and seeing what happens.

Two teams of biologists report in the Proceedings of the National Academy of Sciences that they have used the technique to explore the roles of two master genes that control the appearance of a butterfly's wings. One group has found that a gene called optix has a remarkable role: It controls all the color in a butterfly's wing. When optix is deleted from the Gulf fritillary's eggs, the resulting adult butterflies, which are mostly deep brown, wear a ghostly black and silver livery. That's because in the absence of the optix gene, the butterfly's scales produce melanin, a black pigment, instead of the usual chestnut coloring.

A further surprise came when they turned off the optix gene in a second species, the buckeye. The butterfly's usual browns and yellows disappeared, replaced by scales of a blazing iridescent blue. "That knocked our socks off," one of the scientists said.

A second group has explored the role of a gene called WntA, which plays a powerful role in the patterning of butterflies' wings. The researchers hope in time to understand the patterning mechanism so well that they will be able to recreate the pattern of one butterfly's wings on those of a second species. But understanding butterfly wing patterning is just a step toward addressing larger questions in evolutionary biology. One is the knotty question of how the string of information in a DNA molecule specifies the 3-D structures of the body. The butterfly wing presents this problem more tractably, in just two dimensions.

Another is that of how species evolve different forms. The work of these two groups shows that genes like WntA and optix — master genes that control the activity of other genes — can evolve very different roles in different species.

Nicholas Wade, New York Times

Gut bacteria may play a role in weight loss

Whether a diet works might depend on which bacteria are in your gut. Using feces samples, Danish researchers analyzed the ratio of two gut bacteria, Prevotella and Bacteroides, in 62 overweight people. For 26 weeks, they randomly assigned them to a low-fat diet high in fiber, fruits, vegetables and whole grains or a diet comparable to that of the average Dane.

Those on the high-fiber diet with a high Prevotella to Bacteroides ratio lost an average of 10.9 pounds of body fat, 3½ pounds more than those on the diet with a low ratio. Those on the regular diet with a high Prevotella ratio lost 4 pounds, compared with 5½ pounds for those with a low Prevotella ratio, a statistically insignificant difference.

The study is in the International Journal of Obesity. The lead author, Mads F. Hjorth, an assistant professor at the University of Copenhagen, said that there has been a lot of promise in studying the microbiome, but little in the way of practical results.

"This finding is something that could really be used," he said. Microbiome testing is not routinely available now, "but within a reasonable amount of time it might be a possibility."

Nicholas Bakalar, New York Times

Are you a hair-twirler or a nail-biter?

Are you a toe-tapper, hair-twirler, eye-blinker, head-nodder, nail-biter, knuckle-cracker, skin-picker, lip-licker, shoulder-shrugger or a chin-stroker? Call it a nervous habit or tic, almost everybody has at least one — whether they are aware of it or not. Tics exist on a spectrum ranging from barely noticeable to extremely annoying to potentially injurious. While research has focused mostly on the more severe forms associated with neurobehavioral disorders such as Tourette syndrome and autism, there's a growing realization of the pervasiveness of repetitive, nonfunctional motor behaviors and that the degree to which you engage in them is a barometer of your peace of mind.

Experts divide repetitive, nonfunctional motor behaviors into three overlapping, and not always agreed upon, categories. First, there are classic tics, which typically involve quick, jerky motions of the head, neck or arms preceded by an urge, akin to an itch that needs to be scratched. Tics can also be phonic such as throat-clearing.

Next are stereotypies (pronounced steer-ee-AH-ta-peez), which usually don't have a premonitory feeling and are more fluid and rhythmic like body rocking and leg bobbing. Lastly, there are body focused repetitive behaviors, which are essentially grooming gone awry like compulsive nail-biting, hair-pulling and skin-picking.

All of these behaviors are what experts call "unvoluntary," as opposed to an involuntary muscle twitch. You can stop the tic when asked to or when distracted but the problem is, sooner or later, you go back to doing it. In some circumstances the behavior is distressing to the person, particularly if it is injurious or embarrassing, but more often the movement or mannerism is just maddening to those in proximity.

Kate Murphy, New York Times

Dogs can't smell fear, but they have other reasons to bite

Dogs have remarkable olfactory ability and can be trained to smell a chemical at very low concentration, said Dr. Katherine Albro Houpt, a professor emeritus of behavioral medicine at the Cornell University College of Veterinary Medicine. But there is no proof that dogs can smell fear.

In theory, some dedicated chemist might be able to isolate an odor from the sweat or urine of scared people, and then track the reactions of dogs to it, she said. But such an experiment has not been done.

Many owners believe that their dogs bite people because they smell fear. In fact, Houpt said, the most common victim is someone who reaches out to pet a dog while saying something like, "I love dogs, and they all love me."

So what does set off an attack?

"We do know that dogs are likely to attack rapidly departing people," Houpt said. "They are responding with predatory aggression, not recognition of fear in the victim."

A dog is most likely to ignore someone who is not moving, she added. That is why children are told not to run but to stand still, arms at their sides, when a strange dog approaches.

Sometimes not being afraid is more dangerous than fear, Houpt said. "If you look a dog in the eye, especially a confident, aggressive dog, he is more likely to bite than if you avoid eye contact."

C. Claiborne Ray, New York Times

Songbirds listen to your music

In all likelihood songbirds outside a window are listening when a violinist or other musician practices, says Timothy J. DeVoogd, a professor of psychology at Cornell University, who has long studied both human and bird brains, particularly how the brains of birds encode learned behaviors like song.

"As a shorthand way of thinking, if a bird song sounds musical to human ears, odds are that similar human music will sound songlike to the bird," DeVoogd said. "We know that with the combination of both innate and learned qualities, birds will cue into a particular frequency range, a particular tempo and that the bird then constructs his own song using those qualities."

He thinks that species that create very elaborate songs themselves, like mockingbirds, starlings and catbirds, would be interested in a wider range of human music. But there is a question "whether the bird that is hearing and responding is liking the music, or responding as if it were a potential foe," DeVoogd said. He said there was a lot of research finding that "when a reproducing male hears another bird singing, and it's a good song, he gets angry."

C. Claiborne Ray, New York Times