The Deep Roots of Aging

The evolution of aging might be traced all the way back to how dividing cells split up their load of damage and unwanted byproducts. From Ouroboros: "One approach is to distribute everything equally amongst your two offspring. ... A second approach is to give all the crap to one of the two new cells and keep the other one pristine. Lets call these two cells the crap cell and the pristine cell. ... The crap cell (I love this nomenclature) will become inviable sooner under this strategy, but the alternative would be a symmetric division strategy in which all descendants accumulate garbage, ultimately causing the extinction of the entire lineage. ... Both single-celled yeast and mammalian stem cells employ this asymmetric strategy in order to preserve the viability of an indefinitely dividing lineage. ... One of our initial premises was that aggregates are biochemically hard to handle, which is why they accumulate rather than being degraded. But now we know that cells can bundle aggregates onto actin cables and move them around - why not sort the aggregates into vesicles or membrane blebs and dispose of them? Granted, in order to export an aggregate out of the cell, it would have to cross a membrane, but this would be no more difficult topologically than mitophagy. The obvious (and trivial) answer to this question is 'because it didn't evolve that way,' but I'm curious to know whether there's some compelling reason why it couldn't have evolved that way."



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