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Title: Are periodic tissue patterns produced by Turing reaction-diffusion?
Plain: In 1952 Turing showed that two diffusing chemicals, one activating and one inhibiting, can make spots and stripes from a uniform start. Whether real fingers, hair follicles and feather buds form this way, or by cells pulling on each other, is settled for few systems.
Precise: For a periodic pattern (vertebrate digits, hair follicles, feather buds, fish skin stripes), determine whether reaction-diffusion of the identified molecules, with measured diffusion constants and reaction rates, satisfies the Turing instability conditions and predicts the wavelength and its change with tissue size, or whether a mechanochemical instability driven by cell traction sets the pattern. Answer: a classification per system with the measured parameters.
Settled by: In vivo measurement of diffusion and reaction rates of the candidate molecules plus perturbations of diffusion or traction that shift the wavelength as one model predicts.
Kind: well-posed
Answer type: classification
References: (empty)
Literature status: partially-resolved
Status note: A Bmp-Sox9-Wnt Turing network was proposed for digit patterning (Raspopovic and co-workers, Science 2014, doi 10.1126/science.1252960), while mechanical patterning was reported for feather follicles (Shyer and co-workers, 2017).
Posed since: 1952