Stereotyped cell lineage trees support robust development

Multicellular organisms must have robust development to ensure physiological stability in the face of environmental changes or perturbations. While various mechanisms contributing to developmental robustness have been identified at the subcellular level, those at the intercellular and tissue level remain largely unknown. Our study explores this question using an in vitro directed differentiation model of human embryonic stem cells (hESCs) into lung progenitor cells. Integrated analysis of single-cell transcriptomes and high-density cell lineage trees (CLTs) of the same colonies allowed a fine-resolution recapitulation of known cell types, as well as their differentiation hierarchies and developmental trajectories. Most importantly, we observed stable cell type compositions among many sub-CLTs across biological replicates. Systematic comparison among CLTs by a novel computational framework for CLT alignment suggests that stereotypical development extends beyond stable cell type composition to a degree of significant resemblance in sub-CLT topology. The existence of such sub-CLTs resembling each other not only deepens our understanding of developmental robustness by demonstrating the existence of a stereotyped program, but also suggests a novel perspective for the function of specific cell types in the context of stereotyped sub-CLTs.