In all kingdoms of life, from plants to bacteria or animals, energy expenditure increases with body mass following a conserved non-linear relationship called Kleiber’s power law. This suggests the existence of fundamental processes that set energy expenditure in living organisms. How does the energy expenditure of an organism result from the properties of its constituent cells and organs? How much energy does an egg need to grow and develop into a tadpole? How does a pathological change in an organ’s energy expenditure impact the whole organism metabolism? Is available energy a limiting parameter in certain contexts?  These fundamental questions are one of the most open and important challenge of biology to date.

Two emerging variables that seem to affect energetics at the cellular, tissue and organism level are genome size or genome copy number in the cell (ploidy) and cell size. We previously showed that increasing ploidy of Xenopus laevis embryos results in a reduction of whole embryo energy expenditure which is due to ploidy-driven cell size increase and changes in cellular energetic needs. Our lab develops quantitative approaches in vitro in cells and in vivo in frog embryos to explore fundamental questions at the heart of how ploidy, cell size, and energetics are connected, from the cell to whole organism scale.