In biology and nature, symmetry is often the rule rather than the exception. For example, the human body has symmetrical organs, butterflies have symmetrical wings, and even proteins and RNAs have symmetrical structures. Why does evolution favor symmetry so much? Biologists can’t explain it, but the field of computer science may be able to answer the question: Simulations show that symmetric structures work best.
While symmetric structures don’t necessarily seem as mathematically rigorous, and asymmetries do exist in nature and in living organisms (such as the heart), asymmetry is rarer than symmetry. Why does evolution favor symmetrical structures? Obviously the reason is not good-looking, according to the research team of Iain Johnston, a professor of mathematics at the University of Bergen in Norway, the reason is “simple, easy to do”.
Natural selection automatically preserves survival-friendly traits during evolution. The research team analyzed thousands of protein complexes and RNA structures, molecular models that control the way genes switch on and off, and found that evolution particularly favors symmetry, because it produces symmetric Instructions are more easily embedded in the genetic code, making molecules work more skillfully.
Iain Johnston explains: “Imagine asking a worker to quickly lay the floor. You wouldn’t say rectangles here, diamonds there, diamonds here, wood there; instead you would say: square tiles all.” This simple and easy-to-handle configuration produces highly symmetrical results.
The simulations showed that if simple structures were enough to get the job done, natural selection would take over and take advantage of those structures, with evolution favoring low-complexity, high-symmetry structures over low-symmetry complex structures.
The new paper is published in the Proceedings of the National Academy of Sciences (PNAS).