The week’s most astounding developments from the neobiological frontier.

April 7, 2022

In vitro gametogenesis achieved in rats

Eleven years ago, Japanese researchers at Kyoto University accomplished something almost miraculous called in vitro gametogenesis, where they created mouse embryos in the lab by converting pluripotent stem cells into primordial germ cells—the precursors of sperm and eggs. You can read proto.life’s coverage of some implications of that technique here. It was a first, and they successfully implanted the embryos and delivered live pups, but the achievement has never been repeated with any other mammal. Now another group of researchers at the University of Tokyo and National Institute for Physiological Sciences in Okazaki, Japan, announced they have done it in rats, which are physiologically more similar to humans than mice. Their achievement is important for the future of reproductive medicine and animal breeding studies as it takes scientists “a step closer to achieving applicable systems for other species,” the researchers write. Science

Monumental atlas of human brain scans

A massive project led by researchers at the University of Cambridge in England and the University of Pennsylvania in Philadelphia has collected 123,984 MRI brain scans of 101,457 people ranging in age from 4 months in utero to 100 years old. Together these scans provide a new reference chart showing how brain structures change and how fast they change over the human lifespan—the same way pediatricians have growth charts to benchmark height and weight increases in children. The open access charts detail the dramatic growth of the brain in the first three years of life and reveal brain variation across neurological and psychiatric disorders, the researchers write. Nature

The rocky rise of genetic testing at IVF clinics

Genetic testing of embryos for chromosomal abnormalities, known as aneuploidy, prior to their implantation promises to improve outcomes of in vitro fertilization by prioritizing the most viable embryos. But it’s controversial, remains unproven, and professional bodies like the American Society for Reproductive Medicine cite insufficient evidence to recommend its routine use. It’s also unregulated in the United States—but nevertheless apparently exploding in popularity according to new research from Emory University in Atlanta. Looking at a database of 90 percent of all U.S. IVF cycles from 2014–2018, the researchers showed that in 2018 more than half of all embryos underwent preimplantation genetic testing, up from less than five percent only a decade ago. JAMA

Sexist ideas about girls and math passed down in school

Despite the fact that female students consistently perform as well or better than their male counterparts on standardized math tests, many people still harbor the ill-informed and ugly belief that boys are better at math than girls. Now researchers at New York’s Columbia University and Beijing’s University of Science and Technology have shown that those same pernicious perspectives can be passed from student to student in school. Looking at about 450 classrooms of kids in 112 schools from all the major cities and counties across China, the research found 7th and 9th grade children randomly assigned to classroom groups with other children whose parents held gendered beliefs about mathematics were more likely to adopt those beliefs themselves. Worse, this so-called “intergenerational transmission of gender norms” created self-reinforcing, self-fulfilling prophecies, raising boys’ test scores on midterm exams in those classrooms while driving girls’ scores down. WTF? Nature Human Behavior

Childhood trauma increases risk of multiple sclerosis

Women who are exposed to childhood trauma, especially sexual or emotional abuse, have an increased risk of developing multiple sclerosis, according to the outcomes of 77,997 women in the Norwegian Mother, Father and Child cohort study, analyzed by doctors at Haukeland University Hospital in Bergen, Norway. Childhood abuse is believed to induce stress that alters the immune system and causes dysregulation of the hypothalamic-pituitary-adrenal axis, the researchers say. That leads to oxidative stress and increases the risk of neurodegenerative autoimmune disorders like MS decades later by disrupting the blood-brain barrier. “These results open doors for prevention,” they write. Journal of Neurology, Neurosurgery, and Psychiatry

Robot-assisted dressing achieved with mannequin

A red and black robot in London has the ability to grab a hospital gown, unfold it, move around a bed, lift up each arm of a hospital mannequin, and successfully dress the dummy 90 percent of the time. That may sound mundane, but it’s not trivial. Many people with disabilities, including a large portion of Americans who live in nursing homes, struggle with simple everyday activities like getting dressed, and it turns out it’s not so easy for a robot either. That’s because dressing requires the precise manipulation of soft deformable garments like shirts, which is surprisingly complex for robots because fabrics occupy what experts call “infinite-dimensional configuration space.” Researchers at Imperial College London found a way around this by programming their robot with a neural network that anticipates the best way to grasp a piece of clothing by first analyzing it and then comparing it to simulated data on other fabrics. Science Robotics

Gene variant common among Black Americans associated with increased risk of heart failure

People who carry a genetic variant of the human transthyretin gene, called TTR Val122Ile, suffer significantly increased risk of heart failure, according to a new study from doctors at the University of Alabama. An estimated 3–4 percent of people with African ancestry carry this variant, and it can cause the pathological misfolding of amyloid proteins in the blood and their buildup in the heart. Following 7,514 Black Americans enrolled in the REGARDS study (Reasons for Geographic and Racial Differences in Stroke) for an average of 11 years, the researchers showed people who carry this gene variant were more than twice as likely to suffer heart failure as people who did not. The good news, experts say, is that there are several new treatments approved or awaiting approval for this form of hereditary heart disease. JAMA

Good smells are universal

The human sense of smell is by some measures our most powerful, and evolutionarily speaking, one of the oldest, owing to its key role in foraging, sex, and avoiding danger. But our sense of smell is also aesthetic and plastic—what we think smells nice is a matter of taste, and we can learn to love smells that other people hate. Seeking to understand to what extent these preferences are culturally determined, researchers at the Karolinska Institute in Stockholm, Sweden, and the University of York in England had 235 people from non-Western cultures rank 10 odors in terms of pleasantness and found only a tiny amount of the difference in rankings could be accounted for by culture (a mere 6 percent). Far more powerful is a universality to pleasant smells based on the odor molecules themselves. Shakespeare is right: A rose by any other name would smell as sweet. Current Biology