Tracing the dynamics of stem cell fate

Abstract

The mechanisms that regulate the balance between stem cell duplication and differentiation in adult tissues remain in debate. Using a combination of genetic lineage tracing and marker-based assays, the quantitative statistical analysis of clone size and cell composition has provided insights into the patterns of stem cell fate across a variety of tissue types and organ-isms. These studies have emphasized the role of niche factors and environmental cues in promoting stem cell competence, fate priming, and stochastic renewal programs. At the same time, evidence for injury-induced “cellular reprogramming” has revealed the remarkable flexibility of cell states, allowing progenitors to reacquire self-renewal potential during regen-eration. Together, these findings have questioned the nature of stem cell identity and function. Here, focusing on a range of canonical tissue types, we review how quantitative modeling– based approaches have uncovered conserved patterns of stem cell fate and provided new insights into the mechanisms that regulate self-renewal.