3D mapping of the adult Drosophila brain: Towards a comprehensive digital atlas of secondary lineages. Darren C.C. Wong, Jennifer K. Lovick, Kathy Ngo, Jaison Omoto, Joseph Nguyen, Volker Hartenstein. MCDB, UCLA, Los Angeles, CA.

   The central brain of Drosophila melanogaster is formed by approximately 100 bilaterally symmetrical lineages and these arise from the corresponding 100 neural stem cells (neuroblast) that derive from the early procephalic (head) neurectoderm. Neurons born in the embryo control larval behaviors and these may be reorganized during metamorphosis and subsequently contribute to adult neural circuit. Up until now, there has not been an exhaustive study that endeavors to map every lineage in the adult Drosophila brain. Extensive work has been put into understanding the lineages of the mushroom body and antennal lobe. A map of the secondary lineages has been generated in previous studies from our lab. It was found that the secondary lineages generate a tract (SAT) whose point of entry and trajectory in the neuropile is both invariant and characteristic in nature. Using the global marker BP106 (anti-neurotactin), in concert with green fluorescent protein -labeled clones, we could visualize and follow the SATs of all lineages to generate a comprehensive digital atlas of the secondary lineages at the adult stage. Using the SAT map we were able to identify and classify MARCM clones of secondary lineages in the adult. We show in this presentation the dynamically evolving map of SATs, the way in which SAT entrypoints and trajectories allow us to identify and classify MARCM clones of secondary lineages in the adult. We also present a 3D model of the adult brain, incorporating cell bodies and axonal tracts of secondary lineages.