Systematic detection of subtle spatio–temporal patterns in time-lapse imaging: I. Mitosis

A recent article on syncytial nuclear divisions in early embryos of Drosophila melanogaster presented evidence that the complex spatio–temporal data obtained from time-lapse images were patterned, contrary to previous suggestions based on preliminary observations. However, the reasoning that led to the hypothesis of patterning was informal and unsystematic. Here, we propose a systematic and computerized method for detecting subtle spatio–temporal mitotic patterns, under a general formulation of mitosis as three-dimensional asynchronous processes, of which the earlier data are a special case. The approach involves a rather elaborate application of the concept of permutation test from nonparametric statistics. Far from being limited to mitotic processes, the approach holds general promise for other classes of mass, time-lapse imaging phenomena in cell and developmental biology, such as migration and cell death.