Evidence of common progenitors and patterns of dispersion in rat striatum and cerebral cortex

To correlate clonal patterns in the rat striatum with adult neu-ronal phenotypes, we labeled striatal progenitors between em-bryonic day 14 (E14) and E19 with a retroviral library encoding alkaline phosphatase. In the adult striatum, the majority of E14-labeled neurons (87%) were members of discrete horizon-tal or radial cell clusters. Radial clusters accounted for only 23 % of cell clusters but 34 % of labeled cells. Striatal clones also demonstrated an unexpected widespread pattern of clonal dispersion. The majority of striatal clones were widely dis-persed within the striatum, and 80 % of clones were part of even larger clones that included cortical interneurons. Finally, we observed that PCR-positive cortical interneurons were mem-bers of clones containing both interneurons and pyramids (44%), exclusively interneuron clones (24%), or combined stria-tal–cortical clones (16%), consistent with the view that cortica