• jon

    Posted 112 days ago

  • This was a fantastic piece of reporting and opened my eyes to a new way of thinking about biology. The opening passage wrapped me in immediately:

    Levin is interested in the planarian because, if you cut off its head, it grows a new one; simultaneously, its severed head grows a new tail. Researchers have discovered that no matter how many pieces you cut a planarian into—the record is two hundred and seventy-nine—you will get as many new worms. Somehow, each part knows what’s missing and builds it anew.

    Levin then took this idea and manipulated the regeneration of the planarian by "changing the electrical signals among the worm's cells." This seems like some bizarre creature from a science fiction book, but in reality, humans have some similar features. For example, "human children below the age of approximately seven to eleven are able to regenerate their fingertips." What, then, could we do if we could understand the principles of regenerative biology? Could we regenerate appendages? Vital organs? Live much longer lives?

    The knowledge that electricity is vital to biology is far from new. "Medical electricity" was used in 17th century Europe "to treat impotence and other ailments" for example. But now we have a much deeper sense of how this works.

    Cells employ the bioelectric system as a kind of intercellular internet; they use it to build intricate and expansive communication networks that control the transcription of genes, the contraction of muscles, and the release of hormones. Many drugs target ion channels, using them to treat arrhythmia, epilepsy, and chronic pain.

    But the past century or so has engrained in our psyche that genes are the most important factor in our makeup. Levin challenges this assumptions. Hutson writes that it's "tempting to think that genes contain blueprints for the body and its parts. But there is no map or instruction set for an organ inside a cell." Instead, there is these close interplay between our genetic makeup and the environment. Hutson writes of a recent experiment that showed the importance of this interchange:

    In 2011, Dany Spencer Adams, a postdoc in Levin’s lab, bathed a frog embryo in a voltage-sensitive dye; in the area of tissue where the face would later form, she saw an electrical pattern, which Levin described as resembling “a paint-by-numbers puzzle.” It was a glowing image of a face.

    This technology has very important, pragmatic outcomes. We could regenerate limbs, organs, etc. and save lives or improve lives of people with disabilities. But it also has a deeper, philosophical aspect to it. Understanding the makeup of our bodies not only tells us about ourselves, but about the world we live in more generally. Hutson conculdes with a fascinating experiment that leaves us thinking:

    Researchers have found that, if a slime mold learns something and then crawls over and touches another mold, it can pass on its memory; in 2016, a pair of French scientists showed how one mold could teach another to find some hard-to-reach food through a gooey mind meld.

    The discoveries of science are fascinating and show an amazing diverse and dynamic world. We like to think things are more static and set than they are, because that's comfortable and what we are used to. But it's very clear that we are deeply influenced by environment circumstance.

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