How do simple groups of cells become complex multicellular organisms? This transition occurred repeatedly in the history of life, but its earliest steps lie deep in the past, making them notoriously difficult to study. My lab addresses this problem directly, by watching multicellularity evolve in the laboratory.

In 2018 we started the Multicellularity Long-Term Evolution Experiment (MuLTEE), in which snowflake yeast are selected every day for larger size. Over roughly 3,000 generations, anaerobic populations evolved clusters visible to the naked eye, turning an ancestor that was weaker than gelatin into an organism with the strength and toughness of wood (Bozdag et al. 2023, Nature). Ongoing MuLTEE work looks at how these organisms keep evolving: the spontaneous origin of whole-genome duplication (Tong et al. 2025, Nature), stable ecological coexistence (Pineau et al. 2024, Nature Ecology & Evolution), and metabolically driven flows that let macroscopic clusters keep growing exponentially (Narayanasamy et al. 2025, Science Advances).

Alongside these experiments, we use mathematical models and comparative analyses to ask how multicellular life cycles change evolution itself. Bottlenecks between generations shrink effective population size, increasing the role of genetic drift (Bingham & Ratcliff 2024, PNAS), and organismal size changes how costly it is to set cells aside as soma (Zhang et al. 2026, PNAS). We also use synthetic biology to study how new metabolisms such as phototrophy can be engineered and evolved (Peterson et al. 2024, Current Biology; Burnetti et al. 2026, npj Complexity).

Together, this work aims to explain how a new kind of biological individual arises from single cells, and how it gains the complexity we see in multicellular life today. For more, please see our lab website.