Understanding how asymmetry emerges from an initial symmetrical condition is a major scientific goal. Our project will focus on the emergence of LR asymmetry or Chirality in biological systems, using a complementary, multiscale approach. Our previous work identified Myosin 1D (Myo1D) as a unique chiral factor essential for LR asymmetry and capable of breaking symmetry at all biological scales in Drosophila. While the actin cytoskeleton emerges as a pivotal and conserved pathway for chirality formation, the exact cytoskeletal factors involved in this process, their interplay and the molecular mechanisms involved remain to be explored. Collaborative work between Partners will study molecular-to-organismal chirality through the following tasks: 1. New regulators of Myo1D chiral function and development of the tracheal model system 2. Role of the Myo1D-DAAM interaction to induce cytoskeleton chirality in vitro 3. Role of Myo1D and DAAM in actin organization in cells, minimal tissues and organs in vivo.