How Do Extraembryonic Tissues Shape Development?
Cellular, Developmental, and Regenerative Biology Hub
01 בינואר 2026, 10:15 - 16:00
Gray Faculty of Medical & Health Sciences Building, Room 201
You are cordially invited to a special seminar of the
Cellular, Developmental, and Regenerative Biology Hub
Dr. Ron Hadas
How Do Extraembryonic Tissues Shape Development?
Caltech, Division of Biology and Biological Engineering
Thursday January 1st 2026, at 10:15
Gray Faculty of Medical & Health Sciences Building,
Room 201
Abstract
Mammalian embryogenesis progresses through rapid and coordinated diversification of embryonic and extraembryonic lineages, yet how progenitors emerge across time, space, and lineage relationships remains unresolved. To address this, we built a temporal single-cell model of early development that delineated continuous differentiation trajectories in embryonic and extraembryonic compartments. Combined with targeted perturbations, this framework revealed an early bifurcation between ectoplacental cone and chorion progenitors and a biphasic role for BMP4: an extraembryonic-derived signal essential for placental differentiation, mesoendoderm bifurcation, allantois formation, and germline specification, followed by an embryo-derived BMP4 signal that restricted the primordial germ cell pool.
Yet, transcriptional trajectories alone cannot reveal the actual lineage paths that cells take, or how spatial organization constrains these fate outcomes. To resolve these lineage relationships, we engineered MEMOIR, a spatial lineage-recording mouse that integrates barcode editing, sequential imaging, and Bayesian methods for phylogenetic reconstruction. By retrospectively tracing lineage segregation events, MEMOIR charted epiblast diversification into germ layers, identified the origins of the primordial germline, and linked spatial position to fate choices in placental progenitors.
Together, these complementary approaches reveal how early development unfolds through coordinated signaling, spatial context, and lineage history. Understanding how gene programs generate distinct cell types provides a foundation for uncovering mechanisms of pregnancy failure and informing regenerative medicine strategies.
