Welcome to Quantum Magazine's podcast.

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

I'm Susan Vallage.

Some 700 million years ago, a single cell gave rise to the first animal.

It was a multicellular organism that would

eventually spawn the incredible complexity and diversity of animals we see today. New research is now

offering scientists a fresh perspective on what that cell looked like and how multicellularity

could have emerged from it. It's a transition

that marks one of the most pivotal events in the history of life on Earth.

For well over a century, it's been widely assumed that the ancestors from which the first

animal evolved were simple blobs of identical cells.

Only later, after the animals formed their own branch on the tree of life,

did those cells start to differentiate into various cell types with specialized functions.

But now, painstaking genomic analyses and comparisons between the most ancient animals alive today and their closest non-animal relatives are starting to overturn that theory.

The recent work paints a picture of ancestral single-celled organisms that were already amazingly complex.

They possessed the plasticity and versatility to slip back and forth between several states,

to differentiate as today's stem cells do and then de-differentiate back to a less specialized form.

The research implies that mechanisms of cellular differentiation predated the gradual rise of

multicellular animals. Now, scientists are reporting the most compelling evidence yet for the new

narrative. Their work, and the debate inspired by its publication in nature last year also highlights how difficult

it is to pin down definitive answers to these kinds of evolutionary questions.

It shows how wide Annette researchers have cast for those answers.

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