Nature’s ability to create intricate patterns, like those on fish skin or zebra stripes, has long fascinated scientists and laypeople alike. Dubbed Turing patterns after the mathematician and computer scientist Alan Turing who first studied the phenomenon, they aren’t just aesthetically pleasing; they also play vital roles in animal behavior and ecosystem dynamics, such as camouflage and mate attraction, impacting everything from predator-prey interactions to population dynamics. The physics behind these patterns may also help us to decipher a universal language of pattern formation that can be applied across multiple scientific disciplines.
Past research has suggested that Turing patterns form due to the chemical reaction-diffusion process, where some chemical agents diffuse and react with each other while others inhibit the spread, leading to the spaces between spots. However, this theory fails to explain the striking sharpness of these natural patterns. A recent study on the ornate boxfish adds a new dimension to this picture – diffusiophoresis, which is the movement of particles in response to a concentration gradient. In this case, chromatophores (specialized pigment cells) respond diffusiophoretically to physiological reactions, creating a robust patterning of cells with fine details. By incorporating diffusiophoresis into simulated Turing models, the researchers demonstrated that they could recover the steepness and clarity of patterns in nature.
This study not only provides a more comprehensive understanding of pattern formation, but also unveils the importance of diffusiophoresis. This phenomenon may have an important role in other biological processes too, such as the formation of embryos and tumors. These findings also have implications for various fields, from materials science to biotechnology; possible applications include precise microscale patterning for biomaterial design and cancer treatment.
This study was led by Benjamin M. Alessio, a research assistant, and Ankur Gupta, an Assistant Professor, both in the Department of Chemical and Biological Engineering at University of Colorado Boulder.
Managing Correspondent: Rosella (Qian-Ze) Zhu
Press Article: A new study updates Turing’s theory on how animals get their spots and stripes (CNN)
Original Journal Article: Diffusiophoresis-enhanced Turing patterns (Science Advances)
Image Credit: Unsplash/David Clode