Misaki Foster
Mentor: H. Frederik Nijhout, Ph.D.
Biology Department, Duke University, Durham, North Carolina
Developmental biologists are looking to answer the question of how tissues grow to their species-specific size, and one way to begin to answer that question is by analyzing how patterns of cell division change over place and time. In this study I analyzed the patterns of mitosis and DNA synthesis in developing insect wings, the wing imaginal disks. The wing imaginal discs of caterpillars during their final larval instar are dissected and removed before staining with Hoechst and EdU so as to be able view and analyze mitosis and DNA synthesis, respectively, using a fluorescence microscope. Nuclei undergoing cell division are manually digitized and run through MATLAB programs to create a contour map that conveys where mitosis occurs the most. Overlay images are created to capture and highlight areas where DNA is being synthesized by the cells within the imaginal disc. Each method is repeated throughout different growth stages to determine how the patterns of cell division change as the wings grow and change shape. It is hypothesized that, in any given stage, mitosis will mostly occur in the areas where DNA synthesis does not occur, and vice versa. The results of this study show that cell division is not homogeneously spread across the growing wing, but occurs in ever-changing discrete regions.
