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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A common metaphor for a brain is that of a digital computer, with inputs and outputs and computations happening in between. The metaphor has its problems but there is no doubt about this: brains (neurons) perform computation. When reading a recent Science Advances paper about the computational capacity of life (all of life), I learned that the computational capacity of neurons has been assumed to account for the full computational capacity of life. This assumption excludes nearly all of the…

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In just a few years, our understanding of mutations in human cells has exploded. Huge studies have mapped their characteristics and genomic locations, adding up to a “landscape” of mutation. This work, especially in cancer, has generated catalogues of mutational “signatures” that represent patterns of mutation and can yield clues to mutations underlying disease. One of these signatures, with the license plate-sounding name SBS5, is a standout for at least three reasons: 1) it is very common, in cancers and…

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In my last snippet, I speculated that AI tools recently published in Science and Nature (the “logos” method and an RFdiffusion-based method) could be used to design a protein targeting the intrinsically disordered and toxic N-terminal region of the prion protein. Yet within a week, Nature Biotechnology published a tool that might be even better suited to the task. PepMLM (“Peptide binder design algorithm via Masked Language Modeling”) is a protein language model that designs peptides that will bind to…

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In our first-ever Snippet, I urged you to join me in reverent admiration for bats, those extraordinary mammals that harbor viruses by the truckload but don’t get sick. That’s quite the superpower, but let’s not forget that these mammals can FLY, because their ancestors took mammalian arms and hands and turned them into wings. But how? (And can I do that to my hands?) Here’s one part of the transformation: three of the mammalian fingers (digits II-IV) became spectacularly long,…

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A while back, at a local blood drive, I was surprised (and admittedly a little relieved) to learn that I’m not eligible to donate blood in Austria. I grew up in the UK during the BSE or “mad cow disease” crisis, and in the late 1990s/early 2000s many countries stopped taking blood donations from individuals who spent time in the UK during the crisis. Transmission of infectious prions through blood transfusion has been documented in a handful of CJD (Creutzfeldt-Jakob…

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The hippocampus is an ancient brain structure, dating to the dawn of vertebrates a half billion years ago. Even if you’re not a neuroscientist, you’ve likely heard of it (it’s very well studied) and remembered it (weird name and all). The hippocampus is most famous for roles in memory and in the formation of internal maps of the environment. Interestingly and less known is this: the hippocampus prioritizes its signals based on interests or needs of the animal. That’s great…

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Viruses are adept at entering cells and using RNA or DNA to commandeer cellular systems to make more viruses. Happily, our mammalian cells are skilled at fighting these invaders, and the interferon system is a major tool in the defensive arsenal. Now, perhaps you (like me) tend to think of viruses as invaders from outside the cell; in fact, zillions of viral troublemakers live in our genomes (“the call is coming from inside the house!”), among them the fascinating and…

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Human embryo research is a challenging field – ethically, scientifically, and legally. The “14-day rule,” established in 1990, is a widely adopted limit prohibiting in vitro research on human embryos beyond 14 days post-fertilization. Recently developed stem cell-based embryo models may reduce (but cannot entirely substitute for) the use of donated embryos created by IVF, but the most advanced of these models are similarly limited to around 14 days. In December, the UK national fertility regulator recommended that the government…

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