The central question motivating my research is how do simple organisms evolve into complex organisms? Complex life resulted from a series of “major transitions,” including the emergence of cellular life from groups of interacting molecular replicators, of eukaryotes from prokaryotes, of multicellular organisms from unicells, and of eusocial superorganisms from solitary individuals. The existence of this hierarchy is an outcome, not an initial condition, of the evolutionary process, and understanding the emergence of new levels of the hierarchy is a major goal of evolutionary biology.

I study the evolution of biological complexity using a combination of experimental, theoretical, and genetic approaches. Using the model green alga Chlamydomonas reinhardtii, my lab uses experimental evolution to generate de novo origins of multicellularity under different selective pressures. We use whole-genome sequencing, genome-wide expression analysis, and quantitative genetics to understand the genetic bases of these transitions to multicellular life. In collaboration with Will Ratcliff, I use a combination of analytical and simulation models to understand the role of heritability in major transitions.

 

Relevant publications:

Ratcliff, W. C., M. D. Herron, K. Howell, J. T. Pentz, F. Rosenzweig, and M. Travisano. 2013. Experimental evolution of an alternating uni- and multicellular life cycle in Chlamydomonas reinhardtii. Nature Communications 4:2742. (pdf)