Will Ratcliff, the John C. and Leslie C. Sutherland Professor in the School of Biological Sciences, has been awarded a grant from the John Templeton Foundation. The philanthropic organization’s awards are reserved for scientific research into awe-inspiring topics and will enable Ratcliff to continue groundbreaking research into the origins of multicellular life. 

Ratcliff’s lab has pioneered one of the world’s longest-running evolution experiments.  For more than a decade, the lab’s snowflake yeast has completed tens of thousands of life cycles. This work has provided a unique lens for studying how single-celled organisms make the leap to multicellularity, gradually evolving from simple clumps of cells into organisms. It’s among the first to demonstrate how single cells grow into the multicellular organisms that form the basis of all life, from fungi to fauna. 

“This grant is based on a conceptual breakthrough that emerged only after more than a decade of observing multicellular life evolve,” Ratcliff said.

The research is now at the stage when funding from organizations like Templeton is crucial. Ratcliff’s grant focuses on the concept of “agency,” or how a cell determines its function. 

“The human body contains 39 trillion cells — most of which help us survive and reproduce — yet they themselves won’t pass on their genetic material,” Ratcliff said. “For example, skin cells are never going to make a new human. 

“Multicellular organisms began as small groups where every cell contributed to reproduction. Over time, some cells shifted to supportive roles that didn’t reproduce, instead helping specialized reproductive cells, like sperm and eggs, succeed.”

This shift, in which most cells in an organism have given up the ability to reproduce, represents a fundamental shift biological agency. 

“It’s a key step in the evolution of complex life, as it allows organisms to make things like muscles, neurons, and skin cells,” Ratcliff said. 

But how did it begin? The researchers hypothesize that this shift in agency can occur very early in evolution, as a physical side effect of creating large, tough bodies. As multicellular organisms grow physically larger, cells on the interior may effectively become “stuck,” unable to ever leave the group. Much like a nerve cell in the body, these cells will never form a new organism. Instead, they are incentivized to help the reproductive cells in the organism succeed. 

“We’ve long thought that this type of specialization could only occur after a great deal of genetic modification,” Ratcliff said. “Yet that’s not what appears to be happening in snowflake yeast — it seemingly happens ‘for free’ as a side effect of simple cellular biophysics very early in the transition to multicellularity.” 

With the funding, Ratcliff and his frequent collaborator, School of Physics Associate Professor Peter Yunker, will be able to test this hypothesis using the group’s existing yeast. 

"This award will enable us to address crucial questions about the evolution of multicellularity — and the role that physics plays in the process,” Yunker said.

Their results could fundamentally reshape our understanding of evolution, showing how the simplest life forms can give rise to extraordinary complexity. With each yeast cell, the researchers are uncovering the building blocks of life itself.