Origin and Early Evolution of Life

While a departure from my previous lines of empirical research, I have long had interests in the origin of life and the evolution of eukaryotic cells.

Origin of life: I take the view that life began as autocatalytic ensembles of chemicals adsorbed onto mineral surfaces. In the presence of a constant flux of food and energy, such systems could collectively propagate (grow) and, through an analog of group selection called neighborhood selection, evolve adaptively. This model suggests that cells arose late, possibly via selection for dispersal among discontinuous mineral surfaces, and allows that a nucleic acid-based genetic system might also have originated long after adaptive evolution kicked-in. More concretely, this hypothesis implies that we might be able to induce the formation of new life-like chemical ensembles in the laboratory and detect them via their capacity to evolve adaptively. We have begun such experiments in the Wisconsin Institute for Discovery.

I have laid out the theory in four recent publications: One on selection prior to cell formation, one on the late origins of genetic information encoding, one on how these insights can be combined to suggest a fruitful experimental approach, and on developing a broader theoretical framework for conceptualizing these changes.

Thanks to an NSF EAGER grant from the Chemistry of Life Processes program, we are working to try and develop a microfluidic device that would select for chemical ensembles that self-propagate over surfaces. This project is collaborative with three UW colleagues (Judith Burstyn, Tehshik Yoon, and Kalin Vetsigian) and the microfluidic expert, David Eddington at the University of Illinois – Chicago.

Additionally, I have the honor of being the PI for large multi-institution NSF/NASA Ideas Lab grant: A Chemical Ecosystem Selection Paradigm for the Origin of Life, or CESPOoL, as describe here. I also serve on the steering group for a new research coordination network directed by Chris Kempes at the Santa Fe Institute.

***Prospective Origin of Life Student?***



Origin of eukaryotic cells: In collaboration with Buzz Baum (University College, London) I have developed the inside-out theory for the origin of eukaryotic cell structure. This hypothesis is describe more fully in a paper in BMC Evolutionary Biology and discussed in a review in the American Journal of Botany. Buzz’s lab is exploring parallels between nuclei and archaeal cells. In the Baum lab, Tony Coleman is trying to use new phylogenomic studies to clarify the physiology of the ancestral mitochondrion.