Chapter 8. Hormones and Sex
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By Christie Aschwanden The Olympic stadium was quiet on Wednesday morning, and spectators in the sparsely filled stands seemed to pay little notice to South African runner Caster Semenya as she cruised to an easy win in her first-round heat of the 800 meters. But on Saturday evening, when Semenya will contest the 800-meter final, she’ll have the world’s eyes on her. “There is no more certain gold medal in the Rio Olympics than Semenya,” wrote Ross Tucker, an exercise scientist in South Africa, on his blog, The Science of Sport. “She could trip and fall, anywhere in the first lap, lose 20m, and still win the race.” If she does indeed dominate, some sports fans will be cheering Semenya, while others will be less inclined to celebrate, believing that she has an unfair advantage over her rivals. Semenya made headlines in 2009 amid rumors that track’s governing body, the International Association of Athletics Federations, had required her to undergo tests to confirm that she was female. Media accounts have reported that she has hyperandrogenism, a condition that causes higher-than-average testosterone levels — an allegation that neither Semenya nor the IAAF has publicly confirmed. Semenya’s case is the latest saga in sport’s checkered history of sex testing, a task that is purportedly aimed at creating an even playing field but — as I’ve discussed previously — raises serious questions about how athletics organizations treat women. Her muscular build, deep voice and remarkable results had raised suspicions among some of Semenya’s rivals about whether she was really a woman. “Just look at her,” said Mariya Savinova, a Russian runner now tangled in her country’s doping scandal.
By Melinda Wenner Moyer The science of sleep is woefully incomplete, not least because research on the topic has long ignored half of the population. For decades, sleep studies mostly enrolled men. Now, as sleep researchers are making a more concerted effort to study women, they are uncovering important differences between the sexes. Hormones are a major factor. Estrogen, progesterone and testosterone can influence the chemical systems in the brain that regulate sleep and arousal. Moreover, recent studies indicate that during times of hormonal change—such as puberty, pregnancy and menopause—women are at an increased risk for sleep disorders such as obstructive sleep apnea, restless legs syndrome and insomnia. Women also tend to report that they have more trouble sleeping before and during their menstrual periods. And when women do sleep poorly, they may have a harder time focusing than sleep-deprived men do. In one recent study, researchers shifted the sleep-wake cycles of 16 men and 18 women for 10 days. Volunteers were put on a 28-hour daily cycle involving nearly 19 hours of awake time followed by a little more than nine hours of sleep. During the sleep-shifted period, the women in the group performed much less accurately than the men on cognitive tests. The findings, published in April of this year in the Proceedings of the National Academy of Sciences USA, may help explain why women are more likely than men to get injured working graveyard shifts. In addition, a study conducted in 2015 in teenagers reported that weekday sleep deprivation affects cognitive ability more in girls than in boys. © 2016 Scientific American
by Helen Thompson Some guys really know how to kill a moment. Among Mediterranean fish called ocellated wrasse (Symphodus ocellatus), single males sneak up on mating pairs in their nest and release a flood of sperm in an effort to fertilize some of the female’s eggs. But female fish may safeguard against such skullduggery through their ovarian fluid, gooey film that covers fish eggs. Suzanne Alonzo, a biologist at Yale University, and her colleagues exposed sperm from both types of males to ovarian fluid from female ocellated wrasse in the lab. Nesting males release speedier sperm in lower numbers (about a million per spawn), while sneaking males release a lot of slower sperm (about four million per spawn). Experiments showed that ovarian fluid enhanced sperm velocity and motility and favored speed over volume. Thus, the fluid gives a female’s chosen mate an edge in the race to the egg, the researchers report August 16 in Nature Communications. While methods to thwart unwanted sperm are common in species that fertilize within the body, evidence from Chinook salmon previously hinted that external fertilizers don’t have that luxury. However, these new results suggest otherwise: Some female fish retain a level of control over who fathers their offspring even after laying their eggs. Male ocellated wrasse come in three varieties: sneaky males (shown) that surprise mating pairs with sperm but don’t help raise offspring; nesting males that build algae nests and court females; and satellite males, which protect nests from sneakers but staying out of parenting. |© Society for Science & the Public 2000 - 2016
By Robert Lavine Just the briefest eye contact can heighten empathetic feelings, giving people a sense of being drawn together. But patients who suffer from autism, even in its most high-functioning forms, often have trouble establishing this sort of a social connection with other people. Researchers are delving into what’s going on behind the eyes when these magical moments occur, and the hormones and neural substrates involved may offer hope of helping people with autism. University of Cambridge neuroscientist Bonnie Auyeung and colleagues gave oxytocin—a compound commonly referred to as the “love hormone,” as it’s been found to play roles in maternal and romantic bonding—to both normal men and those with a high-functioning form of autism also called Asperger’s syndrome. The scientists then tracked the eye movements of the study subjects and found that, compared with controls, those who received oxytocin via nasal spray showed increases in the number of fixations—pauses of about 300 milliseconds—on the eye region of an interviewer’s face and in the fraction of time spent looking at this region during a brief interview (Translational Psychiatry, doi:10.1038/tp.2014.146, 2015). Oxytocin, a neuropeptide hormone secreted by the pituitary gland, has long been known to activate receptors in the uterus and mammary glands, facilitating labor and milk letdown. But research on the neural effects of oxytocin has been accelerated by the availability of a nasal spray formulation of the hormone, which can deliver it more directly to the brain, also rich with oxytocin receptors. Auyeung adds that her study used a unique experimental setup. “Other studies have shown that [oxytocin] increases looking at the eye region when presented with a picture of a face,” Auyeung says. “The new part is that we are using a live interaction.”
By Megan Scudellari In late 2013, psychologist Raphael Bernier welcomed a 12-year-old girl and her parents into his office at the University of Washington (UW) in Seattle. The girl had been diagnosed with autism spectrum disorder, and Bernier had invited the family in to discuss the results of a genetic analysis his collaborator, geneticist Evan Eichler, had performed in search of the cause. As they chatted, Bernier noticed the girl’s wide-set eyes, which had a slight downward slant. Her head was unusually large, featuring a prominent forehead. The mother described how her daughter had gastrointestinal issues and sometimes wouldn’t sleep for two to three days at a time. The girl’s presentation was interesting, Bernier recalls, but he didn’t think too much of it—until a week later, when he met an eight-year-old boy with similarly wide-set eyes and a large head. Bernier did a double take. The “kiddos,” as he calls children who come to see him, could have been siblings. According to the boy’s parents, he also suffered from gastrointestinal and sleep problems. The similarities between the unrelated children were remarkable, especially for a disorder so notoriously complex that it has been said, “If you’ve met one child with autism, you’ve met one child with autism.” But Bernier knew that the patients shared another similarity that might explain the apparent coincidence: both harbored a mutation in a gene known as chromodomain helicase DNA binding protein 8 (CHD8). © 1986-2016 The Scientist
Carl Zimmer An eye is for seeing, a nose is for smelling. Many aspects of the human body have obvious purposes. But some defy easy explanation. For biologists, few phenomena are as mysterious as the female orgasm. While orgasms have an important role in a woman’s intimate relationships, the evolutionary roots of the experience — a combination of muscle contractions, hormone release, and intense pleasure — have been difficult to uncover. For decades, researchers have put forward theories, but none are widely accepted. Now two evolutionary biologists have joined the fray, offering a new way of thinking about the female orgasm based on a reconstruction of its ancient history. On Monday, in The Journal of Experimental Zoology, the authors conclude that the response originated in mammals more than 150 million years ago as a way to release eggs to be fertilized after sex. Until now, few scientists have investigated the biology of distantly related animals for clues to the mystery. “For orgasms, we kept it reserved for humans and primates,” said Mihaela Pavlicev, an evolutionary biologist at University of Cincinnati College of Medicine and an author of the new paper. “We didn’t look to other species to dig deeper and look for the origin.” The male orgasm has never caused much of a stir among evolutionary biologists. The pleasure is precisely linked to ejaculation, the most important step in passing on a male’s genes to the next generation. That pleasure encourages men to deliver more sperm, which is evolutionarily advantageous. For women, the evolutionary path is harder to figure out. The muscle contractions that occur during an orgasm are not essential for a woman to become pregnant. And while most men can experience an orgasm during sex, it’s less reliable for women. © 2016 The New York Times Company
Nicola Davis Female orgasm has perplexed scientists, fuelled an equality movement and propelled Meg Ryan to fame. Now researchers say they might have found its evolutionary roots. The purpose of the euphoric sensation has long puzzled scientists as it is not necessary for conception, and is often not experienced by women during sex itself. But scientists in the US have come up with an answer. Human female orgasm, they say, might be a spin-off from our evolutionary past, when the hormonal surges that accompany it were crucial for reproduction. “It is important to stress that it didn’t look like the human female orgasm looks like now,” said Mihaela Pavličev, co-author of the study from Cincinnati children’s hospital. “We think that [the hormonal surge] is the core that was maybe modified further in humans.” Writing in the journal JEZ-Molecular and Developmental Evolution, Pavličev and co-author Günter Wagner from Yale University describe how they delved into the anatomy and behaviour of a host of placental mammals to uncover the evolutionary origin of female orgasm, based on the hormonal surges associated with it. In mammals such as cats and rabbits, these surges occur during sex and play a crucial role in signalling for eggs to be released from the female’s ovaries. By contrast in a variety of other mammals, including humans and other primates, females ovulate spontaneously. © 2016 Guardian News and Media Limited
By PAM BELLUCK The World Health Organization is moving toward declassifying transgender identity as a mental disorder in its global list of medical conditions, with a new study lending additional support to a proposal that would delete the decades-old designation. The change, which has so far been approved by each committee that has considered it, is under review for the next edition of the W.H.O. codebook, which classifies diseases and influences the treatment of patients worldwide. “The intention is to reduce barriers to care,” said Geoffrey Reed, a psychologist who is coordinating the mental health and behavior disorders section in the upcoming edition of the codebook, called the International Classification of Diseases, or I.C.D. Dr. Reed, a professor at the National Autonomous University of Mexico and an author of the new study, said the proposal to remove transgender from the mental disorder category was “not getting opposition from W.H.O.,” suggesting that it appears likely to be included in the new edition. The revised volume would be the first in more than 25 years, and is scheduled to be approved in May 2018. Removing the mental health label from transgender identity would be a powerful signifier of acceptance, advocates and mental health professionals say. “It’s sending a very strong message that the rest of the world is no longer considering it a mental disorder,” said Dr. Michael First, a professor of clinical psychiatry at Columbia University and the chief technical consultant to the new edition of the codebook, which is known by its initials and the edition number I.C.D.-11. “One of the benefits of moving it out of the mental disorder section is trying to reduce stigma.” © 2016 The New York Times Company
Keyword: Sexual Behavior
Link ID: 22484 - Posted: 07.27.2016
By Jesse Singal As anyone who has read much about the subject can attest, the discussion about kids with gender dysphoria — that is, discomfort with their body and the feeling that they should have been born the other sex, or that they are the other sex — can get extremely heated and tricky. Much of the controversy stems from questions of age: How young is too young to help a child socially transition — that is, to change their name and pronoun, and possibly the way they present themselves? To prescribe them cross-sex hormones to begin the process of physically transitioning? For children with persistent gender dysphoria who are approaching adolescence, current best practice is to prescribe them so-called puberty blockers. Delaying the onset of puberty both forestalls the sometimes very uncomfortable experience of a child going through puberty in a body they aren’t comfortable in, and buys them and their families time to figure out what to do. Sometimes, this eventually leads to the prescription of cross-sex hormones, and sometimes it leads to surgery after that. Some people, though, are arguing that kids — particularly those who have socially transitioned at a young age — shouldn’t have to wait that long. Recently in the Guardian, for example, Kate Lyons reported on the current state of this debate in Britain: specifically, whether children who identify as transgender should be given access to cross-sex hormones, or possibly even surgery, at younger ages than what is current practice. © 2016, New York Media LLC.
Keyword: Sexual Behavior
Link ID: 22483 - Posted: 07.27.2016
By Ann Grisold, Oscar, 6, sits at the family dinner table and endures the loneliest hour of his day. The room bustles with activity: Oscar’s sister passes plates and doles out broccoli florets. His father and uncle exchange playful banter. Oscar’s mother emerges from the kitchen carrying a platter of carved meat; a cousin pulls up an empty chair. “Chi fan le!” shouts Oscar’s older sister, in Mandarin Chinese. Time for dinner! “Hao,” her grandfather responds from the other room. Okay. Family members tell stories and rehash the day, all in animated Chinese. But when they turn to Oscar, who has autism, they speak in English. “Eat rice,” Oscar’s father says. “Sit nice.” Except there is no rice on the table. In Chinese, ‘eat rice’ can refer to any meal, but its meaning is lost in translation. Pediatricians, educators and speech therapists have long advised multilingual families to speak one language — the predominant one where they live — to children with autism or other developmental delays. The reasoning is simple: These children often struggle to learn language, so they’re better off focusing on a single one. However, there are no data to support this notion. In fact, a handful of studies show that children with autism can learn two languages as well as they learn one, and might even thrive in multilingual environments. Lost in translation: It’s not just children with autism who miss out when parents speak only English at home — their families, too, may experience frustrating miscommunications. Important instructions, offhand remarks and words of affection are often lost in translation when families swap their heritage language for English, says Betty Yu, associate professor of special education and communicative disorders at San Francisco State University. © 2016 Scientific American,
By Andy Coghlan The final brain edit before adulthood has been observed for the first time. MRI scans of 300 adolescents and young adults have shown how the teenage brain upgrades itself to become quicker – but that errors in this process may lead to schizophrenia in later life. The editing process that takes place in teen years seems to select the brain’s best connections and networks, says Kirstie Whitaker at the University of Cambridge. “The result is a brain that’s sleeker and more efficient.” When Whitaker and her team scanned brains from people between the ages of 14 and 24, they found that two major changes take place in the outer layer of the brain – the cortex – at this time. As adolescence progresses, this layer of grey matter gets thinner – probably because unwanted or unused connections between neurons – called synapses – are pruned back. At the same time, important neurons are upgraded. The parts of these cells that carry signals down towards synapses are given a sheath that helps them transmit signals more quickly – a process called myelination. “It may be that pruning and myelination are part of the maturation of the brain,” says Steven McCarroll at Harvard Medical School. “Pruning involves removing the connections that are not used, and myelination takes the ones that are left and makes them faster,” he says. McCarroll describes this as a trade-off – by pruning connections, we lose some flexibility in the brain, but the proficiency of signal transmission improves. © Copyright Reed Business Information Ltd.
Keyword: Development of the Brain
Link ID: 22474 - Posted: 07.26.2016
By Knvul Sheikh Although millions of women use hormone therapy, those who try it in hopes of maintaining sharp memory and preventing the fuzzy thinking sometimes associated with menopause may be disappointed. A new study indicates that taking estrogen does not significantly affect verbal memory and other mental skills. “There is no change in cognitive abilities associated with estrogen therapy for postmenopausal women, regardless of their age,” says Victor Henderson, a neurologist at Stanford University and the study’s lead author. Evidence of positive and negative effects of such hormone therapy has ping-ponged over the years, with some observational studies in postmenopausal women and research in animal models, suggesting it improves cognitive function and memory. But other previous research, including a long-term National Institutes of Health Women’s Health Initiative memory study published in 2004, has suggested that taking estrogen increases the risk of cognitive impairment and dementia in women over 65 years old. Henderson says one explanation for these contradictory findings may be that after menopause begins there is a “critical period” in which hormone therapy could still benefit relatively young women—if they start early enough. So in their study, which appears in the July 20 online Neurology, Henderson and his team recruited 567 healthy women, between ages 41 and 84, to examine how estrogen affected one group whose members were within six years of their last menstrual period and another whose members had started menopause at least 10 years earlier. © 2016 Scientific American
By William Kenower My youngest son, Sawyer, used to spend far more time relating to his imagination than he did to the world around him. He would run back and forth humming, flapping his hands and thumping on his chest. By the time he was in first grade, attempts to draw him out of his pretend world to join his classmates or do some class work led to explosions and timeouts. At 7 he was given a diagnosis of being on the autism spectrum. That was when my wife, Jen, learned about the practice called joining. The idea behind it, which she discovered in Barry Neil Kaufman’s book “Son-Rise,” is brilliant in its simplicity. We wanted Sawyer to be with us. We did not want him to live in this bubble of his own creation. And so, instead of telling him to stop pretending and join us, we started pretending and joined him. The first time Jen joined him, the first time she ran beside him humming and thumping her chest, he stopped running, stopped thumping, stopped humming and, without a single word from us, turned to her and said, “What are you doing?” We took turns joining him every day, and a week later we got an email from his special education teacher telling us to keep doing whatever we were doing. He’d gone from five timeouts a day to one in a week. The classroom was the same, the work was the same – all that was different was that we had found a way to say to him in a language he could understand, “You’re not wrong.” Emboldened by our success, we set about becoming more fluent in this language. For the next couple of years we taught ourselves to join him constantly. This meant that whatever we were doing had to stop whenever we heard him running back and forth and humming. But we could not join him simply to get him to stop running and thumping and humming. We had to join him without any judgment or impatience. That was the trickiest part. The desire to fix him was great. I had come to believe that there were broken people in need of fixing. Sometimes, I looked like one of those people. I was a 40-year-old unpublished writer working as a waiter. My life reeked of failure. Many days I looked in the mirror and asked, “What is wrong with me?” © 2016 The New York Times Company
Link ID: 22451 - Posted: 07.16.2016
By Rebecca Brewer, Jennifer Murphy, There is a persistent stereotype that people with autism are individuals who lack empathy and cannot understand emotion. It’s true that many people with autism don’t show emotion in ways that people without the condition would recognize. But the notion that people with autism generally lack empathy and cannot recognize feelings is wrong. Holding such a view can distort our perception of these individuals and possibly delay effective treatments. We became skeptical of this notion several years ago. In the course of our studies of social and emotional skills, some of our research volunteers with autism and their families mentioned to us that people with autism do display empathy. Many of these individuals said they experience typical, or even excessive, empathy at times. One of our volunteers, for example, described in detail his intense empathic reaction to his sister’s distress at a family funeral. Yet some of our volunteers with autism agreed that emotions and empathy are difficult for them. We were not willing to brush off this discrepancy with the ever-ready explanation that people with autism differ from one another. We wanted to explain the difference, rather than just recognize it. So we looked into the overlap between autism and alexithymia, a condition defined by a difficulty understanding and identifying one’s own emotions. People with high levels of alexithymia (which we assess with questionnaires) might suspect they are experiencing an emotion, but are unsure which emotion it is. They could be sad, angry, anxious or maybe just overheated. About 10 percent of the population at large — and about 50 percent of people with autism — has alexithymia. © 2016 Scientific American
By Tara Parker-Pope Hoping to alert parents to “red flags” that might signal autism, two advocacy groups yesterday launched a Web site, the ASD Video Glossary, that provides online glimpses of kids with autism to worried parents. But some experts fear the site, though well intentioned, also may cause anxiety among parents whose children are perfectly fine. The site contains videos that show subtle differences in how kids with autism speak, react, play and express themselves. The organizations behind it, Autism Speaks and First Signs, hope that parents who see resemblances in their own kids will be emboldened to seek early diagnosis and treatment, which many experts believe can improve outcomes for kids with autism. Visitors to the new site must register in order to watch the videos, and in the first two hours of its release, more than 10,000 people did so. Yet some researchers fear the video glossary is certain to be troubling for the parents of children without autism, too, because the behavior of kids without the condition can resemble that depicted in the videos. “Just as there’s a spectrum in autism…there’s a spectrum in normal development,” Dr. Michael Wasserman, a pediatrician at Ochsner Medical Center in New Orleans told the Associated Press. “Children don’t necessarily develop in a straight line.” But Amy Wetherby, a professor of communications disorders at Florida State University who helped create the site, said the videos would embolden parents to persist when doctors don’t listen to legitimate concerns about a child’s behavior. As she told the Associated Press, sometimes “parents are the first to be concerned, and the doctors aren’t necessarily worried,” she said. “This will help give them terms to take to the doctor and say, ‘I’m worried about it.”’ © 2016 The New York Times Company
Link ID: 22432 - Posted: 07.13.2016
By David Dobbs It’s difficult to tell what Gina Pace wants unless you already know what she wants. But sometimes that’s easy, and this is one of those times: Gina wants pizza. “I-buh!” she says repeatedly—her version of “I want.” We all do. We are sitting at Abate’s in New Haven, Connecticut, a town famous for—among other things—pizza and science. Gina and her father, Bernardo, who live on Staten Island in New York City, have made the two-hour drive here for both. The pizza is in the oven. The science is already at the table, represented by Abha Gupta, a developmental pediatrician at Yale’s renowned Child Study Center. Gupta is one of the few scientific experts on a condition that Bernardo and Gina know through hard experience. Gina, now 24, was diagnosed 20 years ago with childhood disintegrative disorder, or CDD. CDD is the strangest and most unsettling developmental condition you have probably never heard of. Also known as Heller’s syndrome, for the Austrian special educator who first described it in 1908, it is a late-blooming, viciously regressive form of autism. It’s rare, striking about 1 or 2 in every 100,000 children. After developing typically for two to 10 years (the average is three or four), a child with CDD will suffer deep, sharp reversals along multiple lines of development, which may include language, social skills, play skills, motor skills, cognition, and bladder or bowel control. The speed and character of this reversal varies, but it often occurs in a horrifyingly short period—as short as a couple of months, says Gupta. In about 75 percent of cases, this loss of skills is preceded by days or weeks in which the child experiences intense anxiety and even terror: nightmares and waking nightmares and bouts of confused, jumpy disturbance that resemble psychosis.
By Karl Gruber For most birds the night brings a well-deserved rest. But for some, it is time for more risqué activities. Nocturnal birds sing at night – no surprises there – mainly to attract mates or repel rivals, the same reasons other birds sing at daytime. But a small number of species active by day also occasionally sing at night. Why they invest time and energy in such behaviour has been something of a mystery. Now Antonio Celis-Murillo at the Illinois Natural History Survey in Champaign and his colleagues think they have an answer – and it wasn’t what they expected. The team spent two years studying field sparrows, Spizella pusilla, a common bird across eastern North America. Active during the day, these birds are territorial and largely monogamous, though they engage in occasional infidelity. The researchers observed 28 pairs in the wild, recording the songs of territorial males, as well as those of intruder and neighbouring males. They then conducted playback experiments at night, studying the responses of the pairs. “I was surprised to see what these birds were up to,” says Celis-Murillo. The males sing to attract other male’s partners, and these females are all too willing to wake up for a night-time rendezvous. The team also found that males sang more during periods when females were reproductively receptive, and that the females responded to such song more often when they were fertile. The female’s mate didn’t appear to kick up a fuss and counter-sing – which would be expected if nocturnal songs served to repel rivals. © Copyright Reed Business Information Ltd.
By Jessica Hamzelou TEENAGE pregnancies have hit record lows in the Western world, largely thanks to increased use of contraceptives of all kinds. But strangely, we don’t really know what hormonal contraceptives – pills, patches and injections that contain synthetic sex hormones – are doing to the developing bodies and brains of teenage girls. You’d be forgiven for assuming that we do. After all, the pill has been around for more than 50 years. It has been through many large trials assessing its effectiveness and safety, as have the more recent patches and rings, and the longer-lasting implants and injections. But those studies were done in adult women – very few have been in teenage girls. And biologically, there is a big difference. At puberty, our bodies undergo an upheaval as our hormones go haywire. It isn’t until our 20s that things settle down and our brains and bones reach maturity. “If a drug is going to be given to 11 and 12-year-olds, it needs to be tested in 11 and 12-year-olds,” says Joe Brierley of the clinical ethics committee at Great Ormond Street Hospital in London. Legislation introduced in the US in 2003 and in Europe in 2007 was intended to make this happen but a New Scientist investigation can reveal that there is still scant data on what contraceptives actually do to developing girls. The few studies that have been done suggest that tipping the balance of oestrogen and progesterone during this time may have far-reaching effects, although there is not yet enough data to say whether we should be alarmed. © Copyright Reed Business Information Ltd.
By David Shultz Making eye contact for an appropriate length of time is a delicate social balancing act: too short, and we look shifty and untrustworthy; too long, and we seem awkward and overly intimate. To make this Goldilocks-like dilemma even trickier, it turns out that different people prefer to lock eyes for different amounts of time. So what’s too long or too short for one person might be just right for another. In a new study, published today in Royal Society Open Science, researchers asked a group of 498 volunteers to watch a video of an actor staring out from a screen and press a button if their gazes met for an uncomfortably long or short amount of time (above). During the test, the movement of their eyes and the size of their pupils were recorded with eye-tracking technology. On average, participants had a “preferred gaze duration” of 3.3 seconds, give or take 0.7 seconds. That’s a pretty narrow band for someone on their first date! Making things even harder, individual preferences can also be measured: Researchers found that how quickly people’s pupils dilated—an automatic reflex whenever someone looks into the eyes of another—was a good indicator of how long they wanted to gaze. The longer their preferred gaze, the faster their pupils expanded. The differences are so subtle, though, that they can only be seen with the eye-tracking software—making any attempts to game the system is likely to end up awkward rather than informative. © 2016 American Association for the Advancement of Science.
Carl Zimmer Our genes are not just naked stretches of DNA. They’re coiled into intricate three-dimensional tangles, their lengths decorated with tiny molecular “caps.” These so-called epigenetic marks are crucial to the workings of the genome: They can silence some genes and activate others. Epigenetic marks are crucial for our development. Among other functions, they direct a single egg to produce the many cell types, including blood and brain cells, in our bodies. But some high-profile studies have recently suggested something more: that the environment can change your epigenetic marks later in life, and that those changes can have long-lasting effects on health. In May, Duke University researchers claimed that epigenetics could explain why people who grow up poor are at greater risk of depression as adults. Even more provocative studies suggest that when epigenetic marks change, people can pass them to their children, reprogramming their genes. But criticism of these studies has been growing. Some researchers argue that the experiments have been weakly designed: Very often, they say, it’s impossible for scientists to confirm that epigenetics is responsible for the effects they see. Three prominent researchers recently outlined their skepticism in detail in the journal PLoS Genetics. The field, they say, needs an overhaul. “We need to get drunk, go home, have a bit of a cry, and then do something about it tomorrow,” said John M. Greally, one of the authors and an epigenetics expert at the Albert Einstein College of Medicine in New York. © 2016 The New York Times Company