A good brain somehow balances plasticity (the ability to change) with stability (the need to maintain information and structure). Our brains famously lose some of their plasticity when we become adults, and we more seasoned adults sometimes lament the reduced plasticity that accompanies our hard-earned wisdom. We also wonder how the whole dance is controlled. A new paper in Nature, in a technical tour de force, shows that astrocytes (those long-neglected, oft-forgotten glial cells) are central players in the dance…

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We mammals have some nice features (temperature regulation, big brains that seem too seldom used, etc), but we’re unremarkable when it comes to vision. I assumed this was a standard evolutionary trade-off but the story is weirder than that, as I learned this week when reading a new paper about mammalian retinas. Recall that rods are basically night-vision photoreceptors, able to detect small amounts of light, and cones are the cells that are less sensitive but respond to color. A…

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Last week I wrote about some deviously selfish genetic elements (toxin-antidote systems) and how they evolve. The vast majority of selfish genetic elements, however, are mobile elements we’ll call TEs: tiny modules of DNA that hop around in genomes (including our genomes). These things make up vast tracts of our genomes (more than half, in humans), so it seems that we and our fellow animals are stuck with some kind of truce or coexistence. Animals use elaborate silencing systems to…

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Selfish genes are very interesting phenomena, if too often misunderstood. (They are not “genes for selfishness.”) Animal genomes are overflowing with selfish mobile elements and their debris, but for pure devious self-interest, it’s hard to top toxin-antidote systems. These systems deliver a deadly genetically-encoded toxin to offspring, along with the antidote. The result is a system that ensures its own propagation, because whenever the toxin gene gets separated from the antidote gene*… you know the rest. How can such a…

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Complex cognitive tasks, such as value-based decision-making, can be influenced by sex and by sex steroids, but surprisingly little is known about the nature of these influences or how they happen. This is due, at least in part, to the fact that decades of research looked only at male subjects. In addition, however, there are formidable challenges facing experimenters who aim to explore the effects of sex steroids (such as estrogens) in the brain and behavior. In the case of…

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Human pathogens are diverse (bacteria, viruses, parasites) and destructive. Controlling and killing them is a major goal of humanity, hindered by (among other things) the sophisticated arsenals that pathogens have acquired over millions of years of evolutionary arms races with us. So it follows that we are keen to learn more about pathogen weaponry. A fascinating new preprint presents a powerful new resource in this struggle, with this added angle: the authors seek to not only block pathogenic weapons, but…

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RNA polymerase II is lovingly called “Pol II” by biologists. It’s an unassuming name (maybe a sequel to a blockbuster about a politician or a poltergeist) for a protein that is one of the most central and essential machines of eukaryotic life. Pol II is the main player in transcription, the process by which DNA sequences are read into messenger RNA. It’s hard to imagine a cell staying alive without it, and in fact “prolonged inhibition of RNA Pol II…

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In my last snippet, I wrote about a preprint on antimicrobial peptides as sleep modulators, which got me thinking more generally about interactions between the immune system and behaviour. Growing evidence shows extensive immune system-to-brain signalling and indicates that behavioural changes (like sleeping more and eating less) are not just side effects of being ill. There’s also evidence of signalling going the other way – from brain to immune system (e.g., stress modulates immunity), although this is less well understood.…

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Mitochondria are a bit strange. It’s popular to call them the “powerhouses of the cell,” and that’s true. But they’re also long-ago-domesticated free-living organisms that insist to this day on running their own genetic show, with a private genome and dedicated systems for gene expression. Perhaps understandably, biologists have long pictured the inner mitochondrial compartment (the matrix) as a relatively uniform space where all steps of mitochondrial gene expression—from DNA replication to protein synthesis—happen simultaneously. And yet, given that mitochondria…

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It’s that time of year again – it feels like half the people I know are ill, some forced to stay at home and “sleep it off”. It makes sense that we sleep more when we’re ill, and we know some of the molecular players involved: as early as the 1980s, studies in mammals revealed a role for cytokines, which are hormone-like signalling molecules released during illness. More recently, studies in nematode worms and fruit flies have implicated antimicrobial peptides…

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