Symposium - Developmental Patterning in Space and Time

The Langenbeck-von Virchow-Haus was built in 1914–1915 as the headquarters of the German Society for Surgery and the Berlin Medical Society. It bears the names of two outstanding physicians: Bernhard von Langenbeck and Rudolf Virchow. In the first few decades, the building served as a central meeting place for medical associations. After the Second World War, it was initially used by the Soviet occupation authorities, and from 1950 onwards it housed the People's Chamber of the GDR. During this period, important political decisions and elections took place in the building. After reunification, restitution proceedings were initiated, which were completed in 2003. The building was returned to the medical societies and underwent extensive renovation in 2004–2005. Today, the Langenbeck-von Virchow-Haus once again fulfills its original purpose: it is a modern center for medical meetings, training courses, and conferences, as well as an important architectural monument with a rich history.

In this beautiful setting, speakers and guests of the symposium gathered and admired the stunning architecture of the venue. The initiator and organizer, Kerstin Kaufmann, opened the event with a short introductory lecture in which she presented the theme and goals of the symposium, shared insights into her own research, and explained why the floral ground plan serves as a valuable developmental model system.

The first guest speaker was Caroline Gutjahr, an expert in plant–microbe interactions. In her talk, she introduced the audience to her group’s fascinating work on mycorrhiza — the symbiosis between soil fungi and plant roots that is essential for plant growth and health. She explained how her research explores the molecular factors that regulate the formation and function of these interactions, including how specific plant and fungal genes communicate to establish the symbiosis. Understanding these mechanisms could lead to improved crop resilience, nutrient uptake, and sustainable agricultural practices, demonstrating the broader ecological and practical significance of her work.

This was followed by a much-welcomed coffee break, where participants enjoyed drinks — including the long-awaited coffee — and light snacks. The break also provided an excellent opportunity for networking, exchanging ideas, and forming new connections.

After the break, the focus shifted from the molecular basis of development to the cellular scale. Arun Sampathkumar presented his research on the cytoskeleton and cell wall–based regulation of floral morphogenesis, illustrating how genes guide the formation of specific cell shapes. He explained how the geometry of cells provides directional cues for intracellular components essential to flower development, enabling the transition from a simple convex surface to a highly intricate, convoluted structure. His talk highlighted the sophisticated interplay between genetic regulation, cellular mechanics, and tissue architecture in shaping floral organs.

Offering yet another perspective on the question of shape, Elias Barriga explored how and why immobile cells can transition into collective groups that move together through space and time as a coordinated unit. His 'migrating images' evoked the movement of birds in the sky, shifting and reshaping as if they were a single body. He discussed the triggers that initiate this collective behavior and the mechanisms that regulate it, shedding light on how coordinated cell migration contributes to tissue formation and morphogenesis. Understanding these collective behaviors could provide insights into wound healing, organ development, and pathological conditions such as cancer, where similar coordinated migration plays a critical role.

After lunch, Jan Philipp Junker shifted the perspective toward the field of transcriptomics. Under the theme of reconstructing developmental trajectories from single-cell RNA sequencing, he presented an innovative method that repurposes the CRISPR/Cas9 system for lineage tracing. By introducing genetic barcodes into single cells, his team can track the fate and developmental paths of individual cells over time. This approach provides powerful insights into cellular plasticity, particularly in the context of neuroblastoma, where it helps dissect how both the current environment and a cell’s past history shape cell fate, influence malignancy and ultimately disease development.

Nikolaus Rajewsky, originally trained in developmental biology, now primarily works in systems biology. His research centers on 'spatial omics', an approach that combines single-cell sequencing data with spatial context to reconstruct the organization of tissues. Each cell is transcriptionally unique, and his team uses probabilistic optimal matching algorithms to assign cells to their correct positions. Applied to lung cancer tissue, this method can recreate the full tissue architecture, predict molecular mechanisms, and ultimately enable personalized, mechanism-based drug target predictions. 

Francisca Martinez Real  took the audience into an entirely new area — the emergence of mammalian flight and the molecular mechanisms underlying the development of the physical structures required for it. Her research focuses on bats, and to understand how limbs develop into structures with very different functions, she compares mice and bats to identify both conserved patterns and species-specific adaptations. Using an integrated inter-species limb atlas, she can visualize homologous cell clusters to uncover how wings form. Similar to the development of hands, paws, and fingers, apoptosis removes cells to separate digits. In bats, to form the Chiropatagium, this process is followed by the replacement of the dying cells through fibroblasts, creating the continuous skin layer essential for flight. Fascinating isn't it?

Teng Zhang closed the symposium by bringing the focus back to plants, specifically the diversification of floral ground plans in angiosperms. He shared insights from his work on the woodland strawberry, highlighting how floral patterning evolves. A key process he discussed is phyllotaxis — the arrangement of leaves or floral organs around a stem — which reaches its greatest diversity in the flower. These floral structures can become highly complex, forming spirals, whorls, or combinations of both, shaping the intricate organization of petals, sepals, and other floral organs. Following the transitions in phyllotactic patterning is not only fascinating, it also reveals how organs are precisely positioned during development. This insight helps explain the diversity of plant structures and can guide efforts in crop improvement or synthetic biology.