Yohanns Bellaïche: Mastering multiscale morphology

A s embryonic tissues develop toward their adult state, they experience enormous changes in both form and organization. As Yo-hanns Bellaïche can readily attest, these changes result from the collective effect of many seemingly minor shifts in a signaling pathway or in cytoskeletal organization of individual cells that together cause the dramatic rearrangement of entire tissues. Bellaïche completed his graduate studies on classical problems in developmental biology, such as the establishment of mor-phogen gradients (1). But, later, the emergence of new technologies enabled him to ask entirely new kinds of questions about how cell biological processes drive organ development (2). Now Bellaïche's lab is at the forefront of yet another revolution in developmental biology. He is adapting approaches from the physical sciences to investigate the cell-level changes that underpin the large-scale movements of tissue morphogenesis (3–5), as we learned when we called him at his lab at France's Institut Curie. Were you interested in biology as a child? I was more interested in math and physics. I think those subjects are more highly prized than biology in the French school system, but even once I reached lycée—the French equivalent of high school—I was not at all interested in biology because the way it was taught was more about classification or ecology. It was very descriptive and didn't involve much molecular mechanism. In France, one can either go directly from lycée to a public university or take another few years of education in classes préparatoires. Then one can take the competitive exams and apply for admission into the grandes écoles—the " elite universities. " I was lucky because, even though my family was not rich, the French public schools are free and very good, and I did well enough in my studies that I went ahead with classes préparatoires. I only became interested in biology in my last year of prep school, when my classes started to explore physiology and cell biology in molecular detail. How did you arrange to do your master's degree with Claude Desplan in New York? It was more Claude who arranged it. He's a big fi gure in the fi elds of Drosophila genetics and development, and he's also French. I think he wanted to keep some connection with France, so every year he would recruit a few students from my grandes écoles to join his lab for one or two months. I had learned about …