Branco Weiss Fellow Since
2025
Research Category
Evolutionary medicine, reproductive biology, systems biology
Research Location
Department of Genetics, Harvard Medical School, Boston, USA
Background
Why is reproduction, the most essential part of an organism’s life for evolutionary success, so prone to complication and failure? In humans, a striking 40–60 % of fertilized zygotes are lost before clinical detection. But we are not unique: from opossums to elephant shrews, plains viscachas to tenrecs, many mammals produce substantially more offspring than they ultimately bring to term. Evolutionary theory predicts that this pattern is not simply failure, but a feature of error-prone developmental systems with mechanisms for quality control, where embryos are preferentially selected based on chromosomal integrity, signal production, or allelic compatibility. This process, called developmental selection or embryo selection, is a third evolutionary force besides Darwin’s original natural and sexual selection. This hidden arena of selection helps organisms make strategic decisions about which, and how many, offspring to invest in.
Mathematical models of embryo selection are well-developed and statistical patterns abound, but empirical testing of foundational predictions has long remained out of reach. Today, technological advances in single-cell and spatial genomics and sensitive secretomics of trace signals are making it possible to investigate long-standing questions in a mechanistic way, even in non-traditional species.
Details of Research
Embryo selection is an engine of evolutionary innovation, driving some of the most extreme and rapidly evolving reproductive traits in mammals, including poly-ovulation to enable fertilization of hundreds of surplus eggs, specialized uterine biosensor cell types, and family-planning adaptations like receptive embryo pockets that regulate litter size. Dr. Daniel Stadtmauer plans to investigate lineages of mammals where these unusual traits co-occur, combining field sampling in South Africa with genomic, embryological, and developmental approaches in the lab. By identifying the molecular underpinnings of these unique reproductive strategies, he aims to test whether these systems truly function as predicted to select embryos based on variable attributes, and how fetal signaling and maternal physiology co-evolve.
By combining insights from evolutionary theory with state-of-the-art molecular techniques, Dr. Stadtmauer aims to build a more developmentally informed and empirically grounded understanding of how reproduction evolves.
