Nicole le Douarin
Nicole le Douarin learned to read by overhearing other children’s lessons. Her mother, a public-school teacher, brought her to class when she was three or four years old. Le Douarin colored quietly, but couldn’t help absorbing the tutorials meant for others. Almost 80 years later, she still sounds like a child on the first day of kindergarten when she discusses science: Questions—and the drive to track down answers—bubble out of her.
Unlike typical parents from le Douarin’s village, hers assumed that she would attend university and pursue a career. After graduating from the Sorbonne, le Douarin taught high school, but the lack of intellectual stimulation drove her toward research. She had trouble obtaining a position, given her advanced age (28 years old) and family. Eventually she landed a spot with embryologist Etienne Wolff and volunteered in his lab part time. After two years, she left her teaching job and joined Wolff as a Ph.D. student, studying digestive-tract and liver development in chick embryos.
In 1966, she and her husband, Georges, applied for academic positions at the University of Nantes. The dean did not want couples on his faculty. Nicole could come, he said, but as an assistant, not a professor. Wolff successfully intervened. However, when le Douarin arrived, she received no laboratory space. Exasperated but committed to science, she set up experiments on one of her husband’s benches.
At the time, scientists who studied embryonic development in vertebrates wanted to map out which cells gave rise to specific body parts, but suitable tools did not exist. Marking individual cells was especially difficult.
In the early 1970s, le Douarin pioneered a research approach that would open unexplored and fruitful avenues for the entire enterprise of developmental biology. A geneticist who was working with quail had extra eggs, so he was giving them away. Le Douarin wondered whether quail tissue could trigger chick tissue to specialize normally. She combined material from the two birds in a culture dish and showed that the animals’ cells were physiologically interchangeable. They looked different though: The quail version of a nuclear structure appeared larger and darker than its chick counterpart.
Le Douarin then replaced certain portions of chick embryos with the analogous regions from quail. The chicks developed normally, and quail cells—which retained their distinguishing features—migrated to particular spots. Le Douarin realized that she could study cell fate by transplanting particular pieces of embryos from quail to chick, and then noting where the quail cells wound up.
She used this system to discover how a temporary part of the vertebrate embryo—the neural crest—contributes to adult tissues. She showed that this region is much more important and versatile than previously appreciated. Its cells give rise to the peripheral nervous system, brain, blood, skull, and other body parts.
Le Douarin’s work has allowed her and other researchers to dig into molecular mechanisms that underlie numerous aspects of embryonic development. Furthermore, she has laid a foundation for studying brain disorders and generated crucial knowledge about how the immune system avoids attacking the body’s own tissues.
Author: Evelyn Strauss, Ph.D.