Researchers at the Georgia Institute of Technology in the United States have conducted a landmark study that traces 3,000 generations of a snowflake yeast model organism. The findings come from a long-term evolution experiment and have been reported in Nature, illustrating how persistent selection can drive profound changes in biology over many generations.
The mystery surrounding how multicellular life arose from single-celled ancestors has long puzzled scientists. To peel back the layers of this transformation, the Georgia Tech team embarked on an ambitious project believed to span decades. By watching evolution unfold in real time, they aim to capture the stepwise developments that underlie the leap from individuality at the cellular level to cooperative, multicellular organization across tissues and organs.
In vitro evolution using snowflake yeast has revealed striking physical changes. The engineered strains have become markedly stronger and approximately 20,000 times larger than their ancestral forms. These dramatic shifts are not just about size; they reflect new structural properties that enable the organism to maintain integrity as cells cluster and grow together.
According to the researchers, a novel physical mechanism appears to enable the clusters to reach enormous dimensions. They describe how the bands formed by clustered cells begin to interact in ways that resemble vines spiraling and intertwining. As the cells behave cohesively and the clusters entangle, the overall structure gains stability and mass, which is a key step toward scalable, multicellular organization. Such biophysical evolution provides a plausible pathway for the emergence of large, visible multicellular life and can illuminate the intermediate stages bridging unicellular origins and complex life forms.
Earlier work from another team, notably those connected to Purdue University, has helped illuminate how self-assembly of peptides—molecules essential for initiating and sustaining life—can occur. These peptide formation processes offer critical insight into the molecular prerequisites for life’s beginnings and how simple components might assemble into more complex, self-sustaining systems. The Purdue findings complement the Georgia Tech results by highlighting the chemical avenues that enable biological complexity to arise, supporting a broader narrative about early life and the evolution of cooperation among cells.