Developmental Cell Lineages

Our bodies are built of >30 trillion cells specialized to fulfill diverse roles within our tissues, organs, and organ systems. All these cells originate from a single cell, a zygote formed at conception. From zygote to fetus, and throughout childhood, adolescence, and adulthood, cells divide and commit to different fates in order for the organism to develop, sustain and regenerate. The series of steps that lead from an undifferentiated progenitor cell, such as a stem cell, to one of its several possible specialized descendants constitutes a cell lineage path. Cell lineage paths are organized by organ systems. Each cell lineage path cross-references a Gene Ontology (GO) biological process (The Gene Ontology Consortium 2019), and consists of a series of causally connected cell development steps. Cell development steps describe the transition between cell states during development or differentiation and are characterized by regulators (molecules promoting or inhibiting the step) and, when established, “required input components” (cell state biomarkers required for the action of regulators). Each cell state is characterized by a cell type defined in Cell Ontology, anatomical location from UBERON, and a unique combination of protein and/or RNA markers with references, when available, to CellMarker and PanglaoDB. For a more detailed data model description, please refer to Milacic et al. 2024. Recent technological advances have allowed researchers to harvest high-throughput omics data from single cells of multicellular organisms and use it to track and manipulate cell fates. This opens the door to the possibility of deciphering cell lineage paths at single-cell resolution, a critical requirement for the advancement of regenerative medicine and cancer medicine.

Summary from Reactome (R-HSA-9734767), read 2026-09-23.