How Our Cells Become Our Selves: The Cellular Phylodynamic Biology of Growth and Development

Our lives begin with 1 cell, then 2, then 4, then the trillion cell adult, comprised of cell lineages, tissues, organs. How does this occur? Examination in numbers of cells, N, Cellular Phylodynamics , revealed two previously unappreciated processes: UNI-GROWTH , the slowing of growth that occurs as we become larger, caused by fewer cells dividing, captured by the Universal Mitotic Fraction and Universal Growth Equations , with accuracy confirmed for 13 species, including nematodes, mollusks, and vertebrates; and ALLO-GROWTH , the creation of body parts from Founder Cells , captured by the Cellular Allometric Growth Equation , which describes mitotic expansion by Cell-Heritable change in the Cell Cycle Time . These equations can generate cell lineage approximations, bringing the power of coalescent theory to developmental biology. ### Competing Interest Statement The authors have declared no competing interest.