What determines organ and organism size is a fundamental question that remains unanswered. All through development, organ size increases while being scaled to organism size, until growth terminates. This project addresses the question of how growth is regulated and arrests during development. We propose that energy becomes limiting throughout development and thus sets final size. Indeed, Kleiber's law postulates that the cellular metabolic power decreases with increasing organism mass, limiting the energy assigned for growth. Using Drosphila melanogaster as a model organism, we aim to study growth directly as a 3D dynamic process in order to address the question of how organs and organisms form with consistent size and shape. We will track organism growth in terms of mass and volume as well as organ growth during the larval period of development. By correlating size increase to energy fluctuations, we will uncover to what extent fly larvae follow Kleiber’s law and whether individual organs also follow the same rule. Finally, we will consider three pillars that restrict growth capacity of organs by constraining energy: fractal transportation (branching), morphogenetic gradients and mechanics, and demonstrate how growth arrests during development.
- HORIZON.1.2 - Marie Skłodowska-Curie Actions (MSCA) Main Programme