My research addresses a single fundamental question: how do simple organisms evolve into complex ones? In particular, I am interested in the evolutionary origins of multicellularity. Somehow single-celled organisms, who were successful in their own right, evolved to form new kinds of individuals composed of many cells, multicellular organisms. The evolution of multicellularity is considered a major transition for the evolution of life on earth that made possible significant increases in organismal complexity.
Snowflake yeast and model (image from William Ratcliff, model published [here])
While multicellularity has evolved on dozens of independent occasions, these events occurred millions of years ago and are absent from the fossil record. Recent experiments, however, have made it possible to study this pivotal event in the lab by using microorganisms to evolve primitive multicellularity de novo . Such experimental systems provide excellent opportunities to test hypotheses about the conditions that govern major transitions and facilitate the evolution of additional forms of complexity. We collaborate with talented experimentalists to marry theory with empirical results to uncover general principles of how life evolves to be complex.
Here are some of the topics that we are currently exploring:
- The origins of multicellularity
- Endosymbiosis and the origins of the mitochondria
- Syntrophy and microbial trade
- Life cycles
- Evolutionary transitions in individuality