Why Tigers have Stripes and Leopards have Spots

Alan Turing was a busy man; he cracked the Nazi Enigma code, helped to end the second world war and is widely heralded as the father of computer science – yet somewhere between that he found the time to apply his mathematical mind to the ponderings of why Tigers have stripes and why Leopards have spots – one of nature’s little quirks that have fuelled conversation and folklore alike.

Alan Turing’s theory was that repetitive patterns in biological systems, such as a tiger’s stripes or leopard’s spots, are created by two different morphogens working together – one being an “activator” and one being an “inhibitor.”

Turing suggested – and documented in his 1952 paper The Chemical Basis of Morphogenesis - that one of these chamicals triggered cell activity whilst the other hindered it. The way that those morphogens interact, according to Turing, was responsible for creating the patterns and markings on fur.

Whilst Scientists have previously simulated this theory on computer models, this is the first time that scientists have managed to document the chemicals in action.

Dr Jeremy Green, a reader in Developmental Cell Biology, said the discovery could help progress the next generation of stem cell therapy by indicating how to build complex structures such as organs in a laboratory.

“Regularly spaced structures, from vertebrae and hair follicles to the stripes on a tiger or zebrafish, are a fundamental motif in biology. There are several theories about how patterns in nature are formed, but until now there was only circumstantial evidence for Turing’s mechanism,” Dr. Jeremy Green told TGDaily.com. “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.”

Here’s a video fro the Huffintong Post for those who want this in noisy pictures :)

Dr Green is now studying precisely how the two chemicals react. “We know how the car performs. We now have to look underneath the bonnet,” he said.

The new study is published in the journal Nature Genetics.

Now we can all argue about whether tigers or leopards are cuter and forget about the science behind their stripes.

image courtesy of: 229grade5.edublogs.org

My personal favorite was the Bengal Snow Tiger but now I’m pretty into the Snow Leopard – if someone finds a cub that is “too tame to live in the wild” – dibs.

thanks tumblr

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  1. #1 by TitaniumTeddyBear on February 23, 2012 - 9:17 am

    Very interesting article. Another important piece of the biocomplexity puzzle.


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