SCIENCE LAB SCOOPS : NATURE

A Simpler Drawing Board : Right hand, left hand : How nature uses building blocks in complex patterns.

Symmetry runs rampant in nature. It's present in mirror images, like the right and left halves of elephants or butterflies, and in the repeating patterns of flower petals and starfish arms around a central point - and the rendering above of a light-harvesting complex from a bacterium.

Asymmetry certainly exists - your heart is off to one side in your chest., and male fiddler crabs have one enlarged claw. But symmetrical forms crop up too often to be random. Biologists haven't been sure why. But it seems that a good  answer might be simple efficiency.

Adapting a principle of computer science, researchers have found that the instructions to produce symmetry are easier than asymmetry to embed in genetic code : Symmetry requires repeating one process as needed, rather than constantly reinventing.

The researchers are focused on microscopic structures, but they believe the principle can be extended to more complex ones. ''It would make an awful lot of sense if nature could reuse the program to produce a petal, rather than have a different program for every one of the 100 petals around the sunflower,'' said Ian Johnston, one of the researchers.

Chico Camargo, another co-author in the study said, ''It's like we found a new law of nature.'' [ Kate Golembiewski ].