Lifespan: The Revolutionary Science of Why We Age—and Why We Don't Have To

by David A. Sinclair

IMAGINE A PLANET ABOUT THE SIZE OF OUR OWN, ABOUT AS FAR FROM ITS STAR, rotating around its axis a bit faster, such that a day lasts about twenty hours. It is covered with a shallow ocean of salty water and has no continents to speak of—just some sporadic chains of basaltic black islands peeking up above the waterline. Its atmosphere does not have the same mix of gases as ours. It is a humid, toxic blanket of nitrogen, methane, and carbon dioxide. There is no oxygen. There is no life. Because this planet, our planet as it was 4 billion years ago, is a ruthlessly unforgiving place. Hot and volcanic. Electric. Tumultuous. But that is about to change. Water is pooling next to warm thermal vents that litter one of the larger islands. Organic molecules cover all surfaces, having ridden in on the backs of meteorites and comets. Sitting on dry, volcanic rock, these molecules will remain just molecules, but when dissolved in pools of warm water, through cycles of wetting and drying at the pools’ edges, a special chemistry takes place.1 As the nucleic acids concentrate, they grow into polymers, the way salt crystals form when a seaside puddle evaporates. These are the world’s first RNA molecules, the predecessors to DNA. When the pond refills, the primitive genetic material becomes encapsulated by fatty acids to form microscopic soap bubbles—the first cell membranes.2 It doesn’t take long, a week perhaps, before the shallow ponds are covered with a yellow froth of trillions of tiny...

A nice description of the early precursive cell at the heart of our lineage. All hail the protocell.