Experimental validation of Turning’s thesis explaining patterns in nature
- Nathan Tompkins and others published a paper describing an experiment involving a reaction-diffusion system which evolves patterns that can lead to cell differentiation. This could explain variety of patterns seen in nature such as a Zebra’s stripes, leopard’s spots or the arrangement of leaves.
- As early as in 1952, Alan Turning attempted to explain this origin of static patterns by outlining that diffusion of chemicals across identical cells and their interaction with each other would result in the cells developing differences in chemical concentrations, thus leading to their differentiation.
- On the other hand, if say in a linear array of cells two different species of chemicals are involved, say an activator and inhibitor, it would result in different quantities of each species of chemicals in the different cells. Interaction with water complicates this process further. Turning used differential equations to describe this and predicted that after some time there could emerge six patterns, some of which he identified with the existing patterns in biology.
- In their model Dr. Tompkins showed that their experimental system replicates 5 of these patterns and further throws up a 7th , hitherto unpredicted pattern. They used small number of drops in rings, and long linear arrays in the order of 100 drops and even larger hexagonal, two dimensional arrays of the order 10,000 drops to obtain legitimate results.
- Cell Differentiation