A common set of intricate cell surface patterns are observed in many different kinds of organisms, from insects to plant pollen to fungal spores to eyelash mite carapaces. These patterns are most famous in the popular imagination when they’re found on pollen, and can be reticulate, hexagonal, striped, spiky, knobbed, lobed, etc. To boot, the patterns definitely aren’t random - one tree species will produce billions of nearly identical pollen cells within a single tree and do so stably for millions of years - pollen is a great way to identify things in the fossil record. However, the developmental steps leading to this array always looks identical, no matter the organism or the ultimate output of the pattern. How these patterns are generated or specified has been a mystery.
This paper develops a physical theory showing that the wild variety of observed structures can be produced by the common process of a first-order phase separation of something like a polymer secreted to the surface of the cell. This process accounts for both the variety of patterns and the fact that their development always looks identical. The theory has potential for inspiring a novel class of materials patterned on lengthscales of 100’s of nanometers with functions in optics and water management.
Full Article and Text: PNAS.ORG