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Study Finds First Molecular Genetic Evidence of PTSD Heritability

DNA sequencingA large new study from the Psychiatric Genomics Consortium provides the first molecular genetic evidence that genetic influences play a role in the risk of getting Posttraumatic Stress Disorder (PTSD) after trauma. The report extends previous findings that showed that there is some shared genetic overlap between PTSD and other mental disorders such as schizophrenia. It also finds that genetic risk for PTSD is strongest among women. “We know from lots of data—from prisoners of war, people who have been in combat, and from rape victims—that many people exposed to even extreme traumatic events do not develop PTSD. Why is that? We believe that genetic variation is an important factor contributing to this risk or resilience,” said senior author Karestan Koenen, professor of psychiatric epidemiology at Harvard T.H. Chan School of Public Health who leads the Global Neuropsychiatric Genomics Initiative of the Stanley Center for Psychiatric Research at Broad Institute.

“PTSD may be one of the most preventable of psychiatric disorders,” said first author Laramie Duncan, who did part of the research while at the Broad Institute and is now at Stanford University. “There are interventions effective in preventing PTSD shortly after a person experiences a traumatic event. But they are too resource-intensive to give to everyone. Knowing more about people’s genetic risk for PTSD may help clinicians target interventions more effectively and it helps us understand the underlying biological mechanisms.”

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Scientists Unveil CRISPR-based Diagnostic Platform

A team of scientists from the Broad Institute of MIT and Harvard, the McGovern Institute for Brain Research at MIT, the Institute for Medical Engineering & Science at MIT, and the Wyss Institute for Biologically Inspired Engineering at Harvard University has adapted a CRISPR protein that targets RNA (rather than DNA) as a rapid, inexpensive, highly sensitive diagnostic tool with the potential for a transformative effect on research and global public health.

In a study published today in Science, Broad institute members Feng Zhang, Jim Collins, Deb Hung, Aviv Regev, and Pardis Sabeti describe how this RNA-targeting CRISPR enzyme was harnessed as a highly sensitive detector able to indicate the presence of as little as a single molecule of a target RNA or DNA molecule. Co-first authors Omar Abudayyeh and Jonathan Gootenberg, graduate students at MIT and Harvard, respectively, dubbed the new tool SHERLOCK (Specific High-sensitivity Enzymatic Reporter unLOCKing); this technology could one day be used to respond to viral and bacterial outbreaks, monitor antibiotic resistance, and detect cancer.

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“Smart” Cephalopods Trade Off Genome Evolution for Prolific RNA Editing

Octopus, squid, and cuttlefish are famous for engaging in complex behavior, from unlocking an aquarium tank and escaping to instantaneous skin camouflage to hide from predators. A new study suggests their evolutionary path to neural sophistication includes a novel mechanism: Prolific RNA editing at the expense of evolution in their genomic DNA. The study, led by Joshua J.C. Rosenthal of the Marine Biological Laboratory (MBL), Woods Hole, and Eli Eisenberg and Noa Liscovitch-Brauer of Tel Aviv University is published this week in Cell. The research builds on the scientists’ prior discovery that squid display an extraordinarily high rate of editing in coding regions of their RNA — particularly in nervous system cells — which has the effect of diversifying the proteins that the cells can produce. (More than 60 percent of RNA transcripts in the squid brain are recoded by editing, while in humans or fruit flies, only a fraction of 1 percent of their RNAs have a recoding event.)

“This shows that high levels of RNA editing is not generally a molluscan thing; it’s an invention of the coleoid cephalopods,” Rosenthal says. In mammals, very few RNA editing sites are conserved; they are not thought to be under natural selection. “There is something fundamentally different going on in these cephalopods where many of the editing events are highly conserved and show clear signs of selection,” Rosenthal says.

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Fish Study Shows Important Genome Interactions in Animal Cells

In a new study, researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science examined how the interaction of two genomes in animal cells — the mitochondrial and nuclear genomes — interact to affect adaptation of the Atlantic killifish to different temperatures. They showed that although these genomes are separate physical entities, the mitochondrial genome affects the evolution of the nuclear genome, the genetic material responsible for variations in most traits such as hair color and height. Interactions between these two genomes, which affect everything from health and physiology to fitness, have important consequences for human health and medical interventions such as mitochondrial replacement therapy in embryos.

“Our results suggest that metabolic fitness is not simply a function of the mitochondria but instead is reliant on mitochondrial–nuclear interactions and therefore important for our understanding of physiology, human health and evolution,” said Doug Crawford, professor of marine biology and ecology at the UM Rosenstiel School.

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Blind Tadpoles Learn Visually After Researchers Graft Eyes Onto Tails And Treat Them With Neurotransmitter Drugs

Blind tadpoles were able to process visual information from eyes grafted onto their tails after being treated with a small molecule neurotransmitter drug that augmented innervation, integration, and function of the transplanted organs, according to a paper published online today by researchers at the Allen Discovery Center at Tufts University in npj Regenerative Medicine, a Nature Research journal. The work, which used a pharmacological reagent already approved for use in humans, provides a potential roadmap for promoting innervation – the supply of nerves to a body part – in regenerative medicine. The researchers sought to better understand how the nascent nerves of re-grown or implanted structures integrate into a host. A lack of innervation and integration can be a barrier in regenerative medicine, particularly for sensory organs that must form connections with the host to communicate auditory, visual and tactile information. “For regenerative medicine to move forward and enable the repair of damaged tissues and organ systems, we need to understand how to promote innervation and integration of transplanted organs,” said the paper’s corresponding author, Michael Levin, Ph.D., Vannevar Bush professor of biology and director of the Allen Discovery Center at Tufts and the Tufts Center for Regenerative and Developmental Biology. “This research helps illuminate one way to promote innervation and establish neural connections between a host central nervous system and an implant, using a human-approved small molecule drug.”

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Hair Spacing Keeps Honeybees Clean During Pollination

Image result for images of honey bees with pollenWith honeybee colony health wavering and researchers trying to find technological ways of pollinating plants in the future, a new Georgia Tech study has looked at how the insects do their job and manage to stay clean. According to the study, a honeybee can carry up to 30 percent of its body weight in pollen because of the strategic spacing of its nearly three million hairs. The hairs cover the insect’s eyes and entire body in various densities that allow efficient cleaning and transport. “Without these hairs and their specialized spacing, it would be almost impossible for a honeybee to stay clean,” said Guillermo Amador, who led the study while pursuing his doctoral degree at Georgia Tech in mechanical engineering. This was evident when Amador and the team created a robotic honeybee leg to swipe pollen-covered eyes. When they covered the leg with wax, the smooth, hairless leg gathered four times less pollen.

“If we can start learning from natural pollinators, maybe we can create artificial pollinators to take stress off of bees,” said David Hu, a professor in the Woodruff School of Mechanical Engineering. “Our findings may also be used to create mechanical designs that help keep micro and nanostructured surfaces clean.” The study, “Honeybee hairs and pollenkitt are essential for pollen capture and removal,” is published in the journal Bioinspiration and Biomimetics.

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Scientists Hack A Human Cell And Reprogram It like A Computer

Image result for cellsCells are basically tiny computers: They send and receive inputs and output accordingly. If you chug a Frappuccino, your blood sugar spikes, and your pancreatic cells get the message. Output: more insulin. But cellular computing is more than just a convenient metaphor. In the last couple of decades, biologists have been working to hack the cells’ algorithm in an effort to control their processes. They’ve upended nature’s role as life’s software engineer, incrementally editing a cell’s algorithm—its DNA—over generations. In a paper published today in Nature Biotechnology, researchers programmed human cells to obey 109 different sets of logical instructions. With further development, this could lead to cells capable of responding to specific directions or environmental cues in order to fight disease or manufacture important chemicals.

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Why Are Primates Big-Brained? Researchers’ Answer Is Food for Thought

Brain size in primates is predicted by diet, an analysis by a team of New York University anthropologists indicates. These results call into question “the social brain hypothesis,” which has posited that humans and other primates are big-brained due to factors pertaining to sociality. The findings, which appear in the journal Nature Ecology and Evolution, reinforce the notion that both human and non-human primate brain evolution may be driven by differences in feeding rather than in socialization. “Are humans and other primates big-brained because of social pressures and the need to think about and track our social relationships, as some have argued?” asks James Higham, an assistant professor in NYU’s Department of Anthropology and a co-author of the new analysis. “This has come to be the prevailing view, but our findings do not support it—in fact, our research points to other factors, namely diet.”

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