Controlling Reaction-Diffusion Pattern with Gradients: Lessons from Drosophila, and Trajectories Through Parameter Space

摘要: Since it was first reported by Hafen et al.(1984), the beautifully simple periodic pattern of pair-rule stripes in Drosophila embryos has intrigued theoretical and experimental biologists alike. A primary concern among theoreticians been question whether pairrule are, to any extent, Turing structures, sustained far-from-equilibrium kinetic processes. Current opinion experimentalists tends view that they are not. It is instead proposed precise boundaries all seven each independently specified underlying expression patterns gap genes a concentration-dependent fashion, same manner themselves activated broader maternal gradients. This means iterative operation process gradient reading. The problems with this have already discussed at meeting some length Axel Hunding. His message difficult if not impossible test either critically on basis currently available data. Models depend solely reading require, their extreme form, many untested suppositions. mechanism avoids apparent problems, but there as yet little direct evidence support idea operating, or is, what key components, i. e. morphogens, might be.