Complex animal patterns: A new study could answer this question

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The strikingly patterned boxfish doesn’t lack for detail when it comes to its hexagonal spots and sharp lines — the complex markings are so sharp in the species that even its engineers at the University of Colorado Boulder were mystified. On how to get that distinctive look.

Alan Turing, the famous mathematician who invented modern computing, proposed more than 70 years ago that animals got their patterns by producing chemical agents that would spread through skin tissue, similar to the way coffee creamer spreads. The chemicals will react while other factors inhibit their activity, creating the pattern. But Turing’s theory did not explain how patterns would remain specific in species like the ornate boxfish.

A team of engineers at the University of Colorado Boulder has discovered how a mechanism called diffusion photophoresis can create sharp patterns in a new study published Wednesday in Science Advances. The process of diffusion electrophoresis describes the movement of molecules suspended in a liquid in response to a Concentration gradient of a separate chemical, causing small molecules, in this case chromatophores (pigment cells), to concentrate and clump together.

When scientists calculated the Turing equation, modified to include this process, the simulations they created showed that the path of the particles always created broad lines, unlike the vague, indeterminate spots that Turing’s theory alone would create.

“What kind of intrigued us was that if it’s widespread, the patterns shouldn’t be that sharp…and the colors shouldn’t be that striking,” the study co-author said. Ankur Gupta, assistant professor of chemical and biological engineering at the University of Colorado Boulder. “So, what gives these patterns such amazing sharpness? That’s where diffusion electrophoresis comes in.”

The engineers’ findings suggest that as chemical agents spread, chromatophores form They are also pulled along their path in the process of diffusion electrophoresis, creating spots and lines with a more clearly defined outline. According to a press release On studying.

Gupta said he hopes the findings will promote further research on diffusion phoresis in relation to embryogenesis and tumorigenesis as well as morphogenesis and biological processes of other species.

“The idea of ​​sharpening interfaces is a good idea, and it’s certainly important for biological function,” he said. Dr. Andrew KrauseAssistant Professor of Applied Mathematics at Durham University in the United Kingdom Study Turing theoryin an email.

“Mathematical ideas like diffusion often lead to ‘smooth’ or continuous interfaces, whereas most boundaries in biological tissues (for example, like the boundaries between your organs) are relatively rigid,” said Kraus, who was not involved in the study. “At least one possible way to sharpen gene expression regions.”

Turing’s hypothesis first appeared in 1952 in a paper he wrote titled “The Chemical Basis of Morphogenesis.” His theory argued that animal patterns were not random, but rather a process of chemical reaction and diffusion that systematically led to the appearance of spots on the leopard or stripes on the leopard, according to University of Warwick.

While the diffusion process is a proposed modification to refine Turing’s theory based on the recent study, other solutions may be possible, he said. Jeremy Greenprofessor of developmental biology at King’s College London.

“The cells are very sticky and unlikely to move by diffusion electrophoresis,” Green, who was not involved in the study, said in an email. “The movement of cells to sharpen a Turing pattern (or indeed any boundary) is not a new idea, and can occur not only by chemotaxis (active cell migration) but also by other mechanisms.”

Green said he believes the study is likely to influence future modeling and experimentation, but there are still holes in Turing’s theory that have yet to be explored. Green co-authored A February 2012 study Which found evidence to support Turing’s theory when it comes to the bumps on the mouse’s palate.

“We considered other possibilities in our research and acknowledged the existence of processes such as chemotaxis, that is, cell migration,” Gupta said in an email. “We do not intend to claim that diffusion photophoresis is the only mechanism, but rather that it exists and has not been properly appreciated. Including diffusion helps improve the robustness of such predictions.”