NUSSLEIN-VOLHARD, CHRISTIANE

born Oct. 20, 1942, Magdeburg, Ger. Christiane Nsslein-Volhard, 1995. German developmental geneticist who was jointly awarded the 1995 Nobel Prize for Physiology or Medicine with geneticists Eric F. Wieschaus and Edward B. Lewis (qq.v.) for their research concerning the mechanisms of early embryonic development. Nsslein-Volhard, working in tandem with Wieschaus, expanded upon the pioneering work of Lewis, who used the fruit fly, or vinegar fly (Drosophila melanogaster), as an experimental subject. Her work has relevance to the development of all multicellular organisms, including humans. At Eberhard-Karl University of Tbingen, Nsslein-Volhard received a diploma in biochemistry in 1968 and a doctorate in genetics in 1973. After holding fellowships in Basel and Freiburg, she joined Wieschaus as a group leader at the European Molecular Biology Laboratory in Heidelberg in 1978. In 1981 she returned to Tbingen, where, in 1985, she became director of the Max Planck Institute for Developmental Biology. At Heidelberg, Nsslein-Volhard and Wieschaus spent more than a year crossbreeding 40,000 fruit fly families and systematically examining their genetic makeup at a dual microscope. Their trial-and-error methods resulted in the discovery that of the fly's 20,000 genes, about 5,000 are deemed important to early development and about 140 are essential. They assigned responsibility for the fruit fly's embryonic development to three genetic categories: gap genes, which lay out the head-to-tail body plan; pair-rule genes, which determine body segmentation; and segment-polarity genes, which establish repeating structures within each segment.