An advanced course with classes based on active discussion, lectures, and seminar presentations. Development from embryos and development from stem cells are distinct paradigms for understanding and manipulating the emergence of ordered biological complexity from simplicity. This course focuses on the distinguishing features of stem-cell based systems, ranging from the natural physiological stem cells that are responsible for life-long hematopoiesis in vertebrates (hematopoietic stem cells) to the artificial stem cells, ES and iPS cells, that have now been created for experimental manipulation. Key questions will be how the stem cells encode multipotency, how they can enter long-term self-renewal by separating themselves from the developmental clock that controls development of the rest of the organism, and how the self-renewal programs of different stem cell types can be dismantled again to allow differentiation. Does "stem-ness" have common elements in different systems? The course will also cover the lineage relationships among diverse differentiated cell types emerging from common stem cells, the role of cytokines and cytokine receptors in shaping differentiation output, apoptosis and lineage-specific proliferation, and how differentiation works at the level of gene regulation and regulatory networks. Given in alternate years; not offered 2023-24.