User:Raylynn4752/Christiane Nüsslein-Volhard

During the late 1970’s and early 1980’s, little was known about the genetic and molecular mechanisms by which multicellular organisms develop from single cells to morphologically complex forms during embryogenesis. Nüsslein-Volhard and Wieschaus identified genes involved in embryonic development by a series of  genetic screens, generating random mutations in fruit flies using ethyl methanesulfonate. Some of these mutations affected genes involved in the development of the embryo. They took advantage of the segmented form of Drosophila larvae to address the logic of the genes controlling development. They looked at the pattern of segments and denticles in each mutant under the microscope, and were therefore able to work out that particular genes were involved in different processes during development based on their differing mutant phenotypes (such as fewer segments, gaps in the normal segment pattern, and alterations in the patterns of denticles on the segments). Many of these genes were given descriptive names based on the appearance of the mutant larvae, such as hedgehog, gurken (German: "cucumbers"), and Krüppel ( "cripple"). Later, researchers Pavel Tomancal, Amy Beaton, et. Al, identified exactly which gene had been affected by each mutation, thereby identifying a set of genes crucial for Drosophilaembryogenesis. The subsequent study of these mutants and their interactions led to important new insights into early Drosophila development, especially the mechanisms that underlie the step-wise development of body segments. These experiments are not only distinguished by their sheer scale (with the methods available at the time, they involved an enormous workload), but more importantly by their significance for organisms other than fruit flies.

Her findings led to important realizations about evolution – for example, that protostomes and deuterostomes are likely to have had a relatively well-developed common ancestor with a much more complex body plan than had been conventionally thought.