How does phenotypic heterogeneity of individual cells shape population dynamics?

Phenotypic states of individual cells in a genetically identical population are heterogeneous and often correlated with the fitness of individual cells.The correlations between phenotypic states such as gene expression levels and fitness introduce complexities to understand the causes of cell population behaviors because the average of phenotypic states of cell population is not identical to the typical state of individual cells.Although this problem was well recognized by the researchers in 1930's-60's and several non-trivial theoretical results have been derived, the issue has not been fully addressed experimentally because of technical difficulties.We are currently working on this problem using modern single-cell measurement tools.In this seminar, I will first present our single-cell study on microbial persistence that eventually led us to the aforementioned problem.Then, I will present the experimental examination on the mathematical relation that links the growth rates of individual cells to that of cell population.I will also explain the newly developed microfluidic device used in this experiment, which allows the measurement of individual cell lineages