The Lunatic fringe secretion model can account for the oscillatory gene expression pattern exhibited by the PSM of chick and mouse embryos. It is dependent on local coupling between cells, which allows it for example to not require new cells to ingress into the PSM with an oscillatory initial phase, and to be more resistant to random perturbations. However, oscillations also have an autonomous character, in that the introduction of a coupling boundary at a specific position of the PSM does not significantly affect the oscillatory pattern. Such a behaviour is in agreement with experiments which were previously interpreted as ruling out the existence of coupling between cellular oscillators.
This shows that coupling between the PSM oscillators is compatible with all current experimental data. What's more, such coupling could explain phenomena which have hitherto remained obscure. The model could benefit from an extension to 2 or 3 dimensions, to earlier embryonic times (and explain the way the phase gradient is set up by the spread of the very first wave), and to a strength of coupling set by FGF8 levels (which could then allow to explain the anisotropic effect of FGF8-beads grafts described by Dubrulle et al., 2001). This will be addressed in later studies.
Finally, the model, even though it is based on L-fng activation of Notch signalling (in agreement with biological studies of L-fng), is also compatible with data interpreted as supporting L-fng-mediated repression of Notch signalling.