1/ Not all astrocytes are created equal. We mapped the molecular and spatial landscape of astrocytes in the mouse neocortex — and found five distinct subtypes, organized across cortical layers and white matter.

2/ Here is the twist 🧬. Using high-throughput clonal tracing (TrackerSeq), we discovered that these subtypes originate from two molecularly distinct radial glia lineages.

3/ Lineage 1 🟦: Emx1⁺ radial glia → neurons first, astrocytes later. Lineage 2 🟥: Emx1⁻ radial glia → few neurons, mostly astrocytes. Each lineage gives rise to different astrocyte subtypes — with unique locations and functions.

4/ Why does this matter? Because astrocyte origin shapes astrocyte function. Olig2-lineage astrocytes are synaptogenic — they promote synapse formation. Knock out Olig2, and synaptic density drops.

5/ ⭐️ This study reshapes our understanding of how astrocyte diversity emerges during cortical development.

6/ 🧭 Want to explore the data yourself? Check out our interactive site where you can browse gene expression, subtype markers, lineage relationships, and spatial maps: 🌐 bocchilab.ch/Zhou_et_al_2...