How Tigers Get Their Stripes

For the first time researchers have demonstrated the molecular tango that gives rise to repeating patterns in developing animal embryos.

Feb 22, 2012
Bob Grant

An international team of scientists has identified an activator-inhibitor system that functions to generate patterns in developing vertebrates that was first theorized by renowned mathematician Alan Turing 60 years ago. Turing, who is also considered the father of computer science and helped to crack Nazi Enigma code during World War II, wrote in a 1952 Philosophical Transactions of the Royal Society B paper that chemical substances, called morphogens, could react together and diffuse through a tissue to give rise to patterns such as tentacle patterns on Hydra, whorled leaf patterns in plants, and stripes or spots on big cats like tigers and leopards.

Researchers in the United Kingdom, Japan, and Sweden found that the interaction between two morphogens—fibroblast growth factor and Sonic hedgehog—alternately triggered and hindered cellular activity, leading to the development of ridges, called rugae, in the palates of developing mice. They published their results on the website of Nature Genetics. "There are several theories about how patterns in nature are formed, but until now there was only circumstantial evidence for Turing’s mechanism," senior author and King’s College London cell biologist Jeremy Green told The Telegraph.

Though researchers had modeled Turing's theory using computers, “our study provides the first experimental identification of an activator-inhibitor system at work in the generation of stripes—in this case in the ridges of the mouth palate,” Green added. The mechanism is likely to play a role in the development of other patterns seen in animal development, such as spots or stripes on skin.

Turing, who would have celebrated his 100th birthday this June, was criminally prosecuted with homosexuality, which was a crime in the UK at the time, the month he completed his morphogen paper. He committed suicide 2 years later by eating a cyanide laced apple. “He was a great British genius," Green said. "He had the confidence to take a completely new field, biology, and ask, ‘What can I add to it?’”