Changes in epithelial cell shape and organisation are essential for tissue morphogenesis, regeneration and repair. In recent years, advances in microscopy have made it possible to capture these changes in living animals, but the quantitative analysis of changes in cell shape, behaviour and polarity in large cell populations remains a significant challenge. Here, on p. 1725, Jennifer Zallen and colleagues describe new image analysis software that allows automated image processing, image segmentation, cell tracking, data analysis and data visualization. Using this software, which they term SEGGA (for image SEGmentation, Graphical visualization and Analysis), the team analysed cell behaviours during convergent extension in the Drosophila embryo. Their analyses reveal that cell intercalation is a key mechanism that drives convergent extension and that planar polarity is rapidly established, prior to the onset of elongation, and is dynamically remodelled as cells intercalate. The researchers also demonstrate the general utility of this software by analysing images of epithelial cells from other tissues and organisms. This software, which is freely available and can run on Mac, Windows and Linux operating systems, promises to be a valuable tool for the community.
