Evolutionary Cell Biology
Scaling of the maximum growth rate with organism size for a wide variety of phylogenetic groups. In bacteria, there is positive scaling, whereas in eukaryotes it is reversed.
We surmise that natural selection in bacteria is highly efficient, with growth rate declining with increasing size, owing to the relative reduction in cell walls and membranes. In contrast, the missing growth-rate potential in eukaryotes of increasing size is potentially attributable to a reduction in the efficiency of natural selection.
The horizontal lines denote the absolute upper bounds to growth rate based on the cost and translation capacities of ribosomes.
Remarkably, although we have fairly well-established fields of molecular evolution, genome evolution, and phenotypic evolution, there is no comprehensive field of evolutionary cell biology. Yet, the resources that link molecular and phenotypic evolution reside at the level of cellular architecture. Thus, we are beginning to explore the potential for developing evolutionary theory to explain a wide array of observations from comparative cell biology. Some current interests include the evolution of multimeric proteins, the evolution of cellular surveillance mechanisms (transcription and translation errors), the evolution of maximum growth capacity, evolution of the endomembrane and cytoskeletal systems of eukaryotes, and the coevolution of interacting mitochondrial and nuclear-encoded proteins.
Related to these endeavors:
Mathematical models are being developed to provide population-genetic insights into the scaling of cellular traits across the Tree of Life.
We host an NSF Biological Integration Institute on Mechanisms of Cellular Evolution.
A graduate class has been developed for Evolutionary Cell Biology, for which lecture material and book chapters have been openly available.