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By Emily Anthes Male tanagers are meant to be noticed. Many species of the small, tropical bird sport deep black feathers and splashes of eye-catching color — electric yellows, traffic-cone oranges and nearly neon scarlets. To achieve this flashiness, the birds must spend time and energy foraging for, and metabolizing, plants that contain special color pigments, which make their way into the feathers. A vibrantly colored male is thus sending an “honest signal,” many scientists have long theorized: He is alerting nearby females that he has a good diet, is in good health and would make a worthy mate. But some birds may be guilty of false advertising, a new study suggests. Male tanagers have microstructures in their feathers that enhance their colors, researchers reported Wednesday in the journal Scientific Reports. These microstructures, like evolution’s own Instagram filters, may make the males seem as if they are more attractive than they truly are. “Many male birds are colorful not just because they’re honestly signaling their quality, but because they’re trying to get chosen,” said Dakota McCoy, a doctoral student at Harvard University who conducted the research as part of her dissertation. “This is basically experimental evidence that whenever there’s a high-stakes test in life, it’s worth your while to cheat a little bit.” The new study is an important contribution to the longstanding debate over how, and why, brightly colored feathers evolved in birds, said Geoffrey Hill, an ornithologist and evolutionary ecologist at Auburn University. “Scientists have spent the last 150 years since Darwin and Wallace trying to understand ornaments in animals and especially colors in birds,” he said. “And this is the kind of original approach that helps us.” © 2021 The New York Times Company

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27781 - Posted: 04.21.2021

Nicola Davis It is a trope used in films from King Kong to Tarzan – a male primate standing upright and beating its chest, sometimes with a yell and often with more than a dash of hubris. But it seems the pounding action is less about misplaced bravado than Hollywood would suggest: researchers studying adult male mountain gorillas say that while chest-beating might be done to show off, it also provides honest information. “We found it is definitely a real, reliable signal – males are conveying their true size,” said Edward Wright, co-author of the research from the Max Planck Institute for Evolutionary Anthropology in Germany. Advertisement Writing in the journal Scientific Reports, Wright and colleagues report how they studied chest-beating in six adult male mountain gorillas in the Volcanoes national park in Rwanda. The team used a camera setup involving two parallel green lasers a known distance apart to determine the breadth of each gorilla’s back from a photograph. They then recorded 36 chest-beating episodes among these six males between November 2015 and July 2016, and analysed the recordings. The results revealed that the duration of the chest-beating, number of beats and the rate of the beats during an episode were not associated with the size of the gorilla. However, the average peak frequency of the sound produced was – the larger the gorilla, the lower the frequency of the sound produced. © 2021 Guardian News & Media Limited

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27765 - Posted: 04.10.2021

By Jake Buehler Fairy wrasses are swimming jewels, flitting and flouncing about coral reefs. The finger-length fishes’ brash, vibrant courtship displays are meant for mates and rivals, and a new study suggests that the slow waxing and waning of ice sheets and glaciers may be partly responsible for such a variety of performances. A new genetic analysis of more than three dozen fairy wrasse species details the roughly 12 million years of evolution that produced their vast assortment of shapes, colors and behaviors. And the timing of these transformations implies that the more than 60 species of fairy wrasses may owe their great diversity to cyclic sea level changes over the last few millions of years, scientists report February 23 in Systematic Biology. Within the dizzying assembly of colorful reef fishes, fairy wrasses (Cirrhilabrus) can’t help but stand out. They are the most species-rich genus in the second most species-rich fish family in the ocean, says Yi-Kai Tea, an ichthyologist at the University of Sydney. “That is quite a bit of biodiversity,” says Tea, who notes that new fairy wrasse species are identified every year. Despite this taxonomic footprint, Tea says, scientists knew “next to nothing” about the fairy wrasses’ evolutionary history or why there were so many species. © Society for Science & the Public 2000–2021.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27755 - Posted: 04.03.2021

Tinbete Ermyas & Kira Wakeam Roughly 35 bills are being proposed that would limit or prohibit transgender women from competing in women's athletics. Above, athletes run in the Women's 400 meter final during the Rio 2016 Olympic Games. Shaun Botterill/Shaun Botterill/Getty Images Throughout the country, roughly 35 bills have been introduced by state legislators that would limit or prohibit transgender women from competing in women's athletics, according to the LGBTQ rights group Freedom for All Americans. That's up from only two in 2019. The latest action in this push came last week, when Mississippi Governor Tate Reeves signed into law the "Mississippi Fairness Act." The law prohibits schools from allowing transgender female students to compete in female sports and cites "inherent differences between men and women" as one of the reasons to block these athletes from competition. The often heated debates around these bills have centered on whether transgender women and girls have an unfair advantage over cisgender women — a term used for those who identify with the sex assigned to them at birth. Proponents say the legislation is needed in order to maintain fairness in women's athletics by reducing what they believe is an inherent competitive edge of trans athletes who identify as female. Critics call that a false argument and say the proposals are being used as a way to discriminate against transgender Americans. These proposals, they say, also risk opening the door to humiliating treatment of women and girls who don't fit culturally-accepted notions of femininity. Often missing from the culture-war aspect of the debate is a focus on the type of questions that Dr. Eric Vilain has spent much of his career researching. Vilain, a pediatrician and geneticist who studies sex differences in athletes, says there are no good faith reasons to limit transgender women's participation in sports, especially at the high school level. Vilain has advised both the International Olympic Committee and the NCAA, and says these laws generally aren't based in scientific evidence, but rather "target women who have either a different biology or ... simply look different." © 2021 npr

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27739 - Posted: 03.23.2021

Amanda Heidt In 2015, the National Institute of Neurological Disorders and Stroke released a report stating that more than 600 neurological conditions—including Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, and motor neuron disease, among others—affect an estimated 50 million Americans, a number that is growing each year. Many of these diseases share a common feature in the degradation of the blood-brain barrier (BBB), the cloak of endothelial cells that disposes of the brain’s waste while also providing necessary nutrients. To better understand these diseases and to develop new ways to treat them, scientists rely on increasingly sophisticated cellular models that attempt to mimic the full complexity of the BBB. The advent of hydrogels, microfluidics, and so-called organs on a chip all rely on stable cell lines to build a useful proxy, but new research suggests that all cells may not respond equally to experimentation. The Scientist spoke with Alisa Morss Clyne and Callie Weber, two bioengineers at the University of Maryland whose recent review, published March 16 in APL Bioengineering, makes the case for the inclusion of sex as a biological variable in cell-based experiments. Men and women, a growing body of evidence shows, respond differently to brain diseases in ways that can profoundly influence a study’s findings. Men, for example, are 1.5 times more likely to be diagnosed with Parkinson’s disease and often experience the condition more severely, perhaps because the higher levels of estrogen in premenopausal women shield the BBB from damage. When purchasing cells, Clyne says, scientists are rarely aware of the sex of the original cell donor, but it may ultimately have important consequences for the study of diseases, neurological or otherwise. © 1986–2021 The Scientist

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27738 - Posted: 03.23.2021

By Elizabeth Pennisi For a glimpse of the power of sexual selection, the dance of the golden-collared manakin is hard to beat. Each June in the rainforests of Panama, the sparrow-size male birds gather to fluff their brilliant yellow throats, lift their wings, and clap them together in rapid fire, up to 60 times a second. When a female favors a male with her attention, he follows up with acrobatic leaps, more wing snaps, and perhaps a split-second, twisting backflip. “If manakins were human, they would be among the greatest artists, athletes, and socialites in our society,” says Ignacio Moore, an integrative organismal biologist at Virginia Polytechnic Institute and State University. As biologists have understood since Charles Darwin, such exhibitionism evolves when females choose to mate with males that have the most extravagant appearances and displays—a proxy for fitness. And now, by studying the genomes of the golden-collared manakin (Manacus vitellinus) and its relatives, researchers are exploring the genes that drive these elaborate behaviors and traits. Last month at the virtual meeting of the Society for Integrative and Comparative Biology, Moore and other researchers introduced four manakin genomes, adding to two already published, and singled out genes at work in the birds’ muscles and brains that may make the displays possible. © 2021 American Association for the Advancement of Science.

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27716 - Posted: 03.06.2021

By Jake Buehler You might be able to do a mean celebrity impression or two, but can you imitate an entire film’s cast at the same time? A male superb lyrebird (Menura novaehollandiae) can, well almost. During courtship and even while mating, the birds pull off a similar feat, mimicking the calls and wingbeat noises of many bird species at once, a new study shows. The lyrebirds appear to be attempting to recreate the specific ecological soundscape associated with the arrival of a predator, researchers report February 25 in Current Biology. Why lyrebirds do this isn’t yet clear, but the finding is the first time that an individual bird has been observed mimicking the sounds of multiple bird species simultaneously. The uncanny acoustic imitation of multispecies flocks adds a layer of complexity to the male lyrebird’s courtship song yet unseen in birds and raises questions about why its remarkable vocal mimicry skills, which include sounds like chainsaws and camera shutters, evolved in the first place. Superb lyrebirds — native to forested parts of southeastern Australia — have a flair for theatrics. The males have exceptionally long, showy tail feathers that are shaken extensively in elaborate mating dances (SN: 6/6/13). The musical accompaniment to the dance is predominantly a medley of greatest hits of the songs of other bird species, the function of which behavioral ecologist Anastasia Dalziell was studying via audio and video recordings of the rituals.

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 8: Hormones and Sex
Link ID: 27715 - Posted: 02.28.2021

Catherine S. Woolley, Ph.D. Sex differences in the brain are real, but they are not what you might think. They’re not about who is better at math, reading a map, or playing chess. They’re not about being sensitive or good at multi-tasking, either. Sex differences in the brain are about medicine and about making sure that the benefits of biomedical research are relevant for everyone, both men and women. You may be surprised to learn that most animal research is done in males. This is based on an erroneous view that hormonal cycles complicate studies in female research animals, and an assumption that the sexes are essentially the same down at cellular and molecular levels. But these beliefs are starting to change in neuroscience. New research shows that some fundamental molecular pathways in the brain operate differently in males and females, and not just by a little. In some cases, molecular sex differences are all-or-nothing. Recognition that male and female brains differ at a molecular level has the potential to transform biomedical research. Drugs act on molecular pathways. If those pathways differ between the sexes, we need to know how they differ as early as possible in the long (and expensive) process of developing new medicines and treatments for disease. The bulk of public attention to brain sex differences is focused on structural differences and their purported relationship to behavior or cognition. Yet structural sex differences are actually quite small, and their interpretation is often based on gender stereotypes with little to no scientific justification. © 2021 The Dana Foundation

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 27650 - Posted: 01.15.2021

Mercedes Burns An Asian water dragon hatched from an egg at the Smithsonian National Zoo, and her keepers were shocked. Why? Her mother had never been with a male water dragon. Through genetic testing, zoo scientists discovered the newly hatched female, born on Aug. 24, 2016, had been produced through a reproductive mode called parthenogenesis. Parthenogenesis is a Greek word meaning “virgin creation,” but specifically refers to female asexual reproduction. While many people may assume this behavior is the domain of science fiction or religious texts, parthenogenesis is surprisingly common throughout the tree of life and is found in a variety of organisms, including plants, insects, fish, reptiles and even birds. Because mammals, including human beings, require certain genes to come from sperm, mammals are incapable of parthenogenesis. Creating offspring without sperm Sexual reproduction involves a female and a male, each contributing genetic material in the form of eggs or sperm, to create a unique offspring. The vast majority of animal species reproduce sexually, but females of some species are able to produce eggs containing all the genetic material required for reproduction. Females of these species, which include some wasps, crustaceans and lizards, reproduce only through parthenogenesis and are called obligate parthenogens. A larger number of species experience spontaneous parthenogenesis, best documented in animals kept in zoo settings, like the Asian water dragon at the National Zoo or a blacktip shark at the Virginia Aquarium. Spontaneous parthenogens typically reproduce sexually, but may have occasional cycles that produce developmentally ready eggs. © 2010–2020, The Conversation US, Inc.

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27630 - Posted: 12.19.2020

Claudia Dreifus Questions like “why do men and women act differently?” are age-old, with tangled, deeply buried answers. But that is why Catherine Dulac, a Howard Hughes Medical Investigator and a professor of molecular and cellular biology at Harvard University, has become so well respected by her neuroscientist colleagues for the originality and creativity with which she has brought important answers to light. Though she is trained as a developmental biologist, Dulac takes her research into territory usually explored by social scientists by trying to discern the balance of genetic determination and environmental influence that shapes vital behaviors in mammals. Moreover, she deploys the genetic tools of modern biology to discover the mechanisms that activate these behaviors. Relatively early in her career, Dulac’s investigations into how animals detect pheromones changed our understanding of what those airborne chemicals may signify to the brain. More recently, her experiments identified how the brain circuitry that regulates crucial mating and parenting behaviors works — at least in her model animals, which are mice. She found astonishing evidence that although certain of these behaviors are often described as “male” or “female,” both types of circuitry are present and potentially active in both sexes. As a result, the right combination of triggers can switch an individual creature’s behavior to that of the opposite sex. Scientists are still exploring the full implications of her findings, but Dulac and others are hopeful that they might yield useful insights into conditions like postpartum behavioral disorders. Because of her work’s relevance, in September Dulac, just age 57, was awarded the $3 million Breakthrough Prize in Life Sciences, the richest single personal award in the scientific world. The citation for the prize hailed the success of her work, which connected behaviors to specific neural mechanisms and “overturned decades-old dogma in behavioral science.” Simons Foundation © 2020

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27625 - Posted: 12.15.2020

By Emily Willingham When a male sand-sifting sea star in the coastal waters of Australia reaches out a mating arm to its nearest neighbor, sometimes that neighbor is also male. Undaunted, the pair assume their species’ pseudocopulation position and forge ahead with spawning. Mating, pseudo or otherwise, with a same-sex neighbor obviously does not transfer a set of genes to the next generation—yet several sea star and other echinoderm species persist with the practice. They are not alone. From butterflies to birds to beetles, many animals exhibit same-sex sexual behaviors despite their offering zero chance of reproductive success. Given the energy expense and risk of being eaten that mating attempts can involve, why do these behaviors persist? One hypothesis, hotly debated among biologists, suggests this represents an ancient evolutionary strategy that could ultimately enhance an organism’s chances to reproduce. In results published recently in Nature Ecology & Evolution, Brian Lerch and Maria R. Servedio, from the University of North Carolina, Chapel Hill, offer theoretical support for this proposed explanation. They created a mathematical model that calculated scenarios in which mating attempts, regardless of partner sex, might be worth it. The results predicted that, depending on life span and mating chances, indiscriminate mating with any available candidates could in fact yield a better reproductive payoff than spending precious time and energy sorting out one sex from the other. Although this study does not address sexual orientation or attraction, both of which are common among vertebrate species, it does get at some persistent evolutionary questions: when did animals start distinguishing mates by sex, based on specific cues, and why do some animals apparently remain indiscriminate in their choices? © 2020 Scientific American

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27603 - Posted: 12.05.2020

By Sabrina Imbler In the spring of 2018 at the Montreal Insectarium, Stéphane Le Tirant received a clutch of 13 eggs that he hoped would hatch into leaves. The eggs were not ovals but prisms, brown paper lanterns scarcely bigger than chia seeds. They were laid by a wild-caught female Phyllium asekiense, a leaf insect from Papua New Guinea belonging to a group called frondosum, which was known only from female specimens. Phyllium asekiense is a stunning leaf insect, occurring both in summery greens and autumnal browns. As Royce Cumming, a graduate student at the City University of New York, puts it, “Dead leaf, live leaf, semi-dried leaf.” Mr. Le Tirant, the collections manager of the insectarium since 1989, specializes in scarab beetles; he estimates that he has 25,000 beetles in his private collection at home. But he had always harbored a passion for leaf insects and had successfully bred two species, a small one from the Philippines and a larger one from Malaysia. A Phyllium asekiense — rare, beautiful and, most important, living — would be a treasure in any insectarium. In the insect-rearing laboratory, Mario Bonneau and other technicians nestled the 13 eggs on a mesh screen on a bed of coconut fibers and spritzed them often with water. In the fall, and over the course of several months, five eggs hatched into spindly black nymphs. The technicians treated the baby nymphs with utmost care, moving them from one tree to another without touching the insects, only whatever leaf they clung to. “Other insects, we just grab them,” Mr. Le Tirant said. “But these small leaf insects were so precious, like jewels in our laboratory.” The technicians offered the nymphs a buffet of fragrant guava, bramble and salal leaves. Two nymphs refused to eat and soon died. The remaining three munched on bramble, molted, munched, molted, and molted some more. One nymph grew green and broad, just like her mother. © 2020 The New York Times Company

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27601 - Posted: 12.05.2020

Moles have a pretty tough life. They live underground, in the dark, burrowing through heavy dirt. And when faced with an enemy, there's nowhere to turn — they have to fight. In most mammals, females tend to be at a disadvantage when it comes to face-to-face combat, because they tend to be smaller and less aggressive than males. But female moles have evolved a secret weapon: a hybrid organ made up of both ovarian and testicular tissue. This effectively makes them intersex, giving them an extra dose of testosterone to make them just as muscular and aggressive as male moles. "As a consequence, basically the whole body of the female, they get masculinized," geneticist Darío Lupiáñez told Quirks & Quarks host Bob McDonald. "They become the body builders of nature." Lupiáñez co-led a study to understand how the moles' genes facilitated this advantage, which was recently published in the journal Science. The research was part of a collaboration between the Max Planck Institute for Molecular Genetics and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association in Germany. Same genes, different instructions The team worked with Iberian moles, commonly found in Spain and Portugal, however this intersex adaptation has been documented in at least six mole species. "We know that intersexuality happens in species like humans, dogs or cats. But the difference actually in moles, it happens all the time, so all the females are intersexual. And this is really something unique among mammals," said Lupiáñez. To understand how moles evolved these intersexual traits, researchers fully mapped the genome of the Iberian mole, commonly found in Spain and Portugal. (David Carmona, Department of Genetics, University of Granada, Spain ) ©2020 CBC/Radio-Canada.

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 27530 - Posted: 10.19.2020

By Aayushi Pratap In Rector, Pa., researchers have spotted one strange bird. This rose-breasted grosbeak has a pink breast spot and a pink “wing pit” and black feathers on its right wing — telltale shades of males. But on its left side, the songbird displays yellow and brown plumage, hues typical of females. Annie Lindsay had been out capturing and banding birds with identification tags with her colleagues at Powdermill Nature Reserve in Rector on September 24 when a teammate hailed her on her walkie-talkie to alert her of the bird’s discovery. Lindsay, who is banding program manager at Powdermill, immediately knew what she was looking at: a half-male, half-female creature known as a gynandromorph. “It was spectacular. This bird is in its nonbreeding [plumage], so in the spring when it’s in its breeding plumage, it’s going to be even more starkly male, female,” Lindsay says. The bird’s colors will become even more vibrant, and “the line between the male and female side will be even more obvious.” Gynandromorphs are found in many species of birds, insects and crustaceans such as crabs and lobsters. This bird is likely the result of an unusual event when two sperm fertilize an egg that has two nuclei instead of one. The egg can then develop male sex chromosomes on one side and female sex chromosomes on the other, ultimately leading to a bird with a testis and other male characteristics on one half of its body and an ovary and other female qualities on the other half. © Society for Science & the Public 2000–2020

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27506 - Posted: 10.07.2020

By Cara Giaimo Last year, Katie Goldin was walking in her Los Angeles neighborhood when she saw, in the middle of the sidewalk, two lizards interlocked. The male, flecked like a pebble and about a foot long, had his jaws fully around the slightly smaller female’s head. “He was tenderly clasping her neck in his mouth,” said Ms. Goldin, host of a podcast called “Creature Feature.” “She seemed like she was in a trance.” Even in a world absolutely full of bizarre reproductive strategies, southern alligator lizards are up there. The pair Ms. Goldin spotted were engaged in what’s known as “mate-holding,” a part of the copulatory process in which a male grips a female’s head in his mouth for hours or even days at a time. It’s not clear why the lizards do this. But recently, two research projects have looked into the animals’ ecology and anatomy to better understand where, when and how this strange behavior happens. By approaching the same subject from these very different vantage points, scientists can inform each other’s research, and get a clearer picture of what’s really going on. Spying on lizard sex, for science After Ms. Goldin saw the happy couple, she sent pictures to the Natural History Museum of Los Angeles County. Since 2015, the museum has put out a yearly call for photos and videos of alligator lizards getting it on, which it collects through emails, social media and the platform iNaturalist. The species is the most widespread reptile in Los Angeles. But because the city is a “jigsaw puzzle of private property,” it’s difficult to do traditional wildlife surveys, said Greg Pauly, the museum’s herpetology curator. There are only a handful of published accounts of the lizard’s mating behavior in the scientific literature. © 2020 The New York Times Company

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 11: Emotions, Aggression, and Stress
Link ID: 27500 - Posted: 09.30.2020

By Ann Gibbons Neanderthals have long been seen as uber-masculine hunks, at least compared with their lightweight human cousins, with whom they competed for food, territory, and mates. But a new study finds Homo sapiens men essentially emasculated their brawny brethren when they mated with Neanderthal women more than 100,000 years ago. Those unions caused the modern Y chromosomes to sweep through future generations of Neanderthal boys, eventually replacing the Neanderthal Y. The new finding may solve the decade-old mystery of why researchers have been unable to find a Neanderthal Y chromosome. Part of the problem was the dearth of DNA from men: Of the dozen Neanderthals whose DNA has been sequenced so far, most is from women, as the DNA in male Neanderthal fossils happened to be poorly preserved or contaminated with bacteria. “We began to wonder if there were any male Neanderthals,” jokes Janet Kelso, a computational biologist at the Max Planck Institute for Evolutionary Anthropology and senior author of the new study. But in a technical breakthrough, Max Planck graduate student Martin Petr designed a set of probes that used the DNA sequence from small chunks of modern men’s Y chromosomes to “fish out” and bind with DNA from archaic men’s Y chromosomes. The new method works because the Neanderthal and modern human chromosomes are mostly similar; the DNA probes also reel in the few basepairs that differ. The researchers probed the fragmentary Y chromosomes of three Neanderthal men from Belgium, Spain, and Russia who lived about 38,000 to 53,000 years ago, and two male Denisovans, close cousins of Neanderthals who lived in Siberia’s Denisova Cave about 46,000 to 130,000 ago. When the researchers sequenced the DNA, they got a surprise: The Neanderthal Y “looked more like modern humans’ than Denisovans’,” Kelso says. © 2020 American Association for the Advancement of Science.

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27484 - Posted: 09.25.2020

Zeeya Merali Discovering the “on-and-off switch” for good parenting in male and female mouse brains has earned Catherine Dulac, a molecular biologist at Harvard University in Cambridge, Massachusetts, one of this year’s US$3-million Breakthrough prizes — the most lucrative awards in science and mathematics. Three other major prizes in biology, plus two in physics and one in mathematics, were also announced on 10 September, together with a number of smaller prizes. “Catherine Dulac has done amazing work that has really transformed the field,” says biologist Lauren O’Connell at Stanford University, California. Dulac’s team provided the first evidence that male and female mouse brains have the same neural circuitry associated with parenting, which is just triggered differently in each sex1. “It went against the dogma that for decades said that male and female brains are organized differently,” says O’Connell. Dulac says she was stunned to learn that she had won the award. “My brain froze, then I began to tear up,” she says, adding that it had been a long road to acceptance, because others had initially been sceptical of her work. In the 1990s, Dulac isolated the pheromone receptors in mice that govern sex-specific social behaviours. Virgin male mice usually attack other males and kill pups. But Dulac found that if their pheromone receptors were blocked, they would attempt to mate with both males and females, and virgin males would even care for pups. Pheromone-blind females, by contrast, would attempt to mount males. © 2020 Springer Nature Limited

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27467 - Posted: 09.12.2020

By Katharine Q. Seelye Shere Hite, who startled the world in the 1970s with her groundbreaking reports on female sexuality and her conclusion that women did not need conventional sexual intercourse — or men, for that matter — to achieve sexual satisfaction, died on Wednesday at her home in London. She was 77. Her husband, Paul Sullivan, confirmed the death to The Guardian. The newspaper quoted a friend of Ms. Hite’s as saying that she had been treated for Alzheimer’s and Parkinson’s diseases. Her most famous work, “The Hite Report: A Nationwide Study of Female Sexuality” (1976), challenged societal and Freudian assumptions about how women achieved orgasm: It was not necessarily through intercourse, Ms. Hite wrote; women, she found, were quite capable of finding sexual pleasure on their own. However obvious her conclusions might seem today, they were seismic at the time and “sparked a revolution in the bedroom,” as Ms. magazine reported. For all the women who had faked orgasm during intercourse, the Hite Report helped awaken their sexual power and was seen as advancing the liberation of women that was rapidly underway. The book became an instant best seller and has been translated into a dozen languages. More than 48 million copies have been sold worldwide. What set the Hite Report apart from other studies were the questionnaires at the heart of it. More than 3,000 women were given anonymity in answering the queries, allowing them to write candidly and open-endedly — not in response to multiple-choice questions — about their experiences. “Researchers should stop telling women what they should feel sexually and start asking them what they do feel sexually,” Ms. Hite wrote. She described her questionnaires as a “giant rap session on paper.” In revelatory first-person testimonials, more than 70 percent of the respondents shattered the notion that women received sufficient stimulation during basic intercourse to reach climax. Rather, they said, they needed stimulation of the clitoris but often felt guilty and inadequate about it and were too embarrassed to tell their sexual partners. © 2020 The New York Times Company

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27464 - Posted: 09.12.2020

Sean Ingle The double Olympic 800m champion Caster Semenya appears to have lost her long-running legal battle against regulations requiring women with high testosterone to take medication to compete internationally between 400m and a mile. A Swiss federal tribunal said on Tuesday that it supported a decision by the court of arbitration for sport last year that track and field’s policy for athletes with differences in sex development (DSD) was “necessary, reasonable and proportionate” to ensure fair competition in women’s sport. Charley Hull withdraws from ANA Inspiration after positive Covid-19 test Read more “Based on these findings, the Cas decision cannot be challenged,” the tribunal said. “Fairness in sport is a legitimate concern and forms a central principle of sporting competition. It is one of the pillars on which competition is based.” It now looks impossible for Semenya, the London 2012 and Rio 2016 gold medallist, to defend her title in Tokyo. She responded to the news by accusing World Athletics of being on the “wrong side of history”. “I am very disappointed by this ruling, but refuse to let World Athletics drug me or stop me from being who I am,” she said. “Excluding female athletes or endangering our health solely because of our natural abilities puts World Athletics on the wrong side of history. I will continue to fight for the human rights of female athletes, both on the track and off the track, until we can all run free the way we were born.” The South African was almost unstoppable until World Athletics implemented a new policy for DSD athletes, including Semenya, that compelled them to reduce their testosterone levels to less than 5 nmol/L if they wanted to compete in elite events between 400m and a mile. © 2020 Guardian News & Media Limited

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 27462 - Posted: 09.09.2020

A line of elephants trundles across a dusty landscape in northern Botswana, ears flapping and trunks occasionally brushing the ground. As they pass a motion-activated camera hidden in low shrubbery, photos record the presence of each elephant. What's special about this group? It's only males. Female elephants are known to form tight family groups led by experienced matriarchs. Males were long assumed to be loners, because they leave their mother's herd when they reach 10 to 20 years of age. A new study shows that teenage males aren't anti-social after all. Younger male elephants were seen tagging along behind older males as they travel from place to place. It's more evidence in an emerging body of research that shows older males — like their female counterparts — play an important role in elephants' complex society. For the study published Thursday in the journal Scientific Reports, researchers analyzed photos of 1,264 sightings of male African savannah elephants travelling toward the Boteti River in 2017 and 2018. They found that younger males seldom travelled alone and older males most often led groups of mixed ages. "Mature male elephants often take a position at the front of the line when they are leading the group" to streams or seasonal grazing grounds, said Diana Reiss, director of the Animal Behavior and Conservation Program at Hunter College, who was not involved in the new study. "In human societies, grandparents are valued because they make really important contributions — helping with childcare and passing down knowledge gained over decades," she said. "We're now learning this pattern is also true for some other long-lived mammals, including dolphins, whales and elephants." Photos of 1,264 sightings of male African savannah elephants travelling toward the Boteti River in 2017 and 2018 showed that younger males seldom travelled alone and older males most often led groups of mixed ages. (Connie Allen) ©2020 CBC/Radio-Canada

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 11: Emotions, Aggression, and Stress
Link ID: 27452 - Posted: 09.05.2020