Drosophila melanogaster syncytial nuclear divisions are patterned: time-lapse images, hypothesis and computational evidence

Time-lapse microscopy of biological systems has provided new and exciting information about the dynamics of cellular and developmental events. However, these events are often complex and difficult to analyze. This paper describes a study in which computation was indispensable for formulating and evaluating a cellular/developmental hypothesis directly from observations of time-lapse fluorescence images. Previous analyses of time-lapse microscopy sequences ofDrosophila melanogasterembryonic syncytial nuclear cycles 10–13, when the nuclei form an evenly spaced monolayer at the surface of the embryo, have failed to identify any pattern in these divisions. However, computational analysis of the data has provided evidence that the direction of syncytial nuclear mitosis is not random, but is clearly influenced by the relative positions of neighboring nuclei. An approximate law governing mitotic direction that is based on a scheme that compromises among “votes” made by neighboring nuclei is introduced.