John W. Sedat

The scientific efforts are directed toward deciphering higher order chromosome structure, an unsolved problem, using Drosophila as a model system. Interestingly, those studies have required development, in collaboration with his colleague, David Agard, of several microscope systems, both optical and electron microscopic, to adequately visualize and quantitate the intricate chromosomal organization. The microscope system development continues. The biology research has two main, complementary directions. The first concerns the defined, three-dimensional folding patterns of Drosophila chromosomes and possible changes in the three-dimensional architecture as a function of development. The polytene chromosomes were chosen as a model for interphase nuclei. The results indicate defined folding patterns of interphase chromosomes in polytene nuclei within larval organs and in diploid nuclei in early embryos. Efforts are also directed to ask questions as to function, for example, do the mechanisms of maintaining such order play any role in complex genetic phenomena? The second research direction is the analysis of the structure of diploid anaphase chromosomes. The chromosomes are ordered structures, as shown in three-dimensional structural approaches.