Event:

The developing brain faces the daunting task of generating billions of cells, each with their proper type, morphology, position, and connectivity. The ability of cells to self-assemble into a large integral brain, and in particular the ability of neurons to project axons over long distances, suggests cells have implicit knowledge of their global position. How do cells access global spatial information, despite being only able to measure their immediate extracellular environment? We developed a model whereby cell division induces a global address space that cells can leverage to estimate their global position from local gene expression: If mitotic daughters remain close to each other and exhibit gene expression similar to their parent’s, then cells’ progenies form nested regions identifiable by their similarity to their common progenitor. This hierarchy may act as an address space by allowing cells, in principle, to estimate their global position from their local environment by comparing local expression to an ancestral expression profile. We tested the predictions of this model with respect to the spatiotemporal organization of gene expression, by analyzing spatial transcriptomic data acquired at various developmental stages in mouse and zebrafish. We find that, despite the highly dynamic nature of gene expression during brain development, the spatial covariance of gene expression is organized as a global static hierarchy, as predicted by the model. This hierarchy persists throughout mouse development, and is conserved across mouse and zebrafish brains, suggesting that the address space may play a fundamental role in the developmental algorithms that coordinate tissue organization throughout both ontogeny and phylogeny.

Zoom link
https://gwdg.zoom.us/j/84472240120?pwd=WGVXUEoxMlZOUnZjMkpUcE5yVCsvZz09
Meeting-ID: 844 7224 0120
Kenncode: 185545