Comprehensive Lineage Tracing Maps the Landscape of Cell Fate Decisions in Mouse Embryogenesis

Area of Science:

• Developmental Biology
• Genomics
• Computational Biology

Background:

• Mapping mammalian embryogenesis cell fates is challenging due to scale, diversity, and developmental plasticity.
• Previous lineage tracing methods lacked the resolution to capture a significant portion of cell divisions.

Purpose of the Study:

• To construct a comprehensive cell fate map of mammalian embryogenesis.
• To quantitatively analyze cell fate decisions, lineage relationships, and developmental timing.
• To understand the interplay of lineage, spatial position, and signaling in cell fate determination.

Main Methods:

• Utilized PEtracer technology for heritable genetic marking of dividing cells.
• Reconstructed lineage trees from over 1.5 million cells across 16 mouse embryos (E7.5-E10.0).
• Integrated lineage data with deep transcriptional profiling.

Main Results:

• Resolved approximately 75% of cell divisions, creating detailed lineage trees.
• Revealed a highly reproducible lineage architecture across embryos, despite developmental flexibility.
• Quantified cell fate biases, progenitor pool sizes, and the timing of fate restriction.
• Demonstrated how lineage, spatial position, and signaling jointly influence cell fate outcomes.

Conclusions:

• The study provides a quantitative, lineage-resolved framework for understanding mammalian embryogenesis.
• The generated dataset serves as a reference for developmental hypotheses at an organismal scale.
• Highlights the balance between developmental robustness and flexibility in mammalian embryos.