Defining lineage potential and fate behavior of precursors during pancreas development

Pancreas development involves a coordinated process in which an early phase of cell segregation and patterning is proceeded by a longer phase of lineage restriction, expansion and extensive tissue remodeling. By combining quantitative clonal lineage tracing and whole-mount reconstruction with proliferation kinetics and single-cell transcriptional profiling, we define the functional basis of pancreas morphogenesis. Our results show that the large-scale organization of tissue can be traced to the activity of self-renewing precursors that localize at the termini of growing ductal branches and act collectively to drive serial rounds of stochastic ductal bifurcation balanced by termination. During this process, multipotent precursors give rise to self-renewing acinar-committed precursors, which are conveyed with growing ducts, as well as fate-restricted ductal progenitors that expand the trailing ducts and give rise to delaminating islet precursors. Together, these findings define quantitatively how the functional behavior and lineage progression of heterogeneous pools of the pancreatic precursors that define the organization of the organ. Overall design: Single cell RNA sequencing of pancreatic E13.25 and E15.25 cells