Welcome to Quantum Magazine's podcast.

Each episode, we bring you stories about developments in science and mathematics.

I'm Susan Vallett.

In 1891, German biologist Hans Dries split two cell sea urchin embryos in half.

He found that each of the separated cells then

grew into its own complete but smaller larva. Somehow, the halves knew to change their entire

developmental program. At that stage, the blueprint for what they would become had apparently

not been drawn out yet, at least not in

ink. For more than a century, scientists have been trying to understand what goes into making

this blueprint and how instructive it is. It's now known that some form of positional information makes gene switch on and off throughout the embryo.

This gives cells distinct identities based on their location.

But the signals carrying that information seem to fluctuate widely and chaotically,

the opposite of what you might expect for an

important guiding influence. Robert Brewster is a systems biologist at the University of

Massachusetts Medical School. He says the embryo is a noisy environment. But it somehow comes

together to give you a very reproducible, crisp, and exact body plan.

The same precision and reproducibility emerge from a sea of noise again and again in many cellular

processes. That mounting evidence is leading some biologists to a bold hypothesis that cells may extract

as much useful information in their complex surroundings as possible, so they can find solutions

to life's challenges that are not just good, but optimal. Biologists haven't traditionally cast

analyses of life as optimization problems.

The complexity of living systems makes them hard to quantify, and it can be difficult to discern what would be optimized.

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