protocerebral embryonic fiber tract founder cluster P2l fiber tract founder cluster fly_anatomy.ontology Fiber tract founder cluster located at the junction between the protocerebrum and the deutocerebrum. Along with the P2m founder cluster, fibers from the P2l form a transverse track that pioneers the supraesophageal commissure. This cluster derives from the Dc1 or the Dc2 lineage. VFB:FBbt_00001609 FBbt:00001609 See Nassif et al. (1998) for a schematic view of founder cluster location.