How chicken feathers and shark scales are formed in the SAME way: Theory developed by the enigma code-breaking genius Alan Turing explains the mechanism

  • Alan Turing developed his theory of a reaction-diffusion system in 1952 
  • It has long been used as an explanation for how many animals get their patterns
  • Researchers have now shown it is pivotal in the development of shark scales
  • The finding sheds light on how distantly related animals are evolutionary linked 
  • Scientists believe this could help in designing new energy efficient materials
  • e-mail



Tooth-like scales of sharks and chicken feathers are created by the same process and explained by a theory from the legendary code-breaker Alan Turing.

His reaction-diffusion theory is widely accepted as the way in which many animals get unique patterns in their feathers, fur, teeth and teeth.

It has now been extended to include the development of shark scales – a group of animals that are very distantly related to the other known animals.

The findings help explain how the scales of a shark evolved to reduce drag and be more energy efficient while swimming.

Scientists believe this patterning could help in designing shark-inspired materials to improve energy efficiency.

Scroll down for video  

Scientists studied the small-spotted catshark at about 80 days post-fertilisation using RD modelling and gene expression analysis (pictured).  They found that the same core genes involved with feather patterning also underpin the development of shark scales 

Alan Turing developed the brilliant reaction-diffusion system in 1952, just two years before his tragic death.

Prior to this he was famously involved in the cracking of the Enigma code used by the Germans during the Second World War.  

His equations describe how molecular signals can interact to form complex patterns in a variety of different systems.

In the paper, published in the journal Science Advances, researchers compared the patterning of shark scales to that of chicken feathers.

Dr Gareth Fraser, now at the University of Florida, said: ‘We started looking at chicks and how they develop their feathers.

‘We found these very nice lines of gene expression that pattern where these spots appear that eventually grow into feathers.

‘We thought maybe the shark does a similar thing, and we found two rows on the dorsal surface, which start the whole process.’ 

They found that the same core genes involved with feather patterning also underpin the development of shark scales. 

Researchers know believe that these common genetic signals may be involved in the patterning of a variety of ‘epithelial appendages’. 

  • Baby shark that DROWNED when it got stuck in a discarded… Garbage-eating shark drone takes to the water in Dubai to… Harrowing picture illustrates the menace of plastic in our… How to ultrasound a SHARK: Incredible footage shows daring…

Share this article

These include spines, teeth, hair, fur, scales and feathers and has likely contributed to this process for at least 450 million years – the entire history of vertebrates.

From the scales of a snake to the feathers of a flamingo, modern vertebrates showcase an array of epithelial appendages.

These structures all possess similar developmental positioning in relation to one another because they grow from a common place within skin cells, known as the epithelial placode.

Although evidence has been found in many animals, the theory was never proved for more distantly related vertebrates that diverged from the same ancestral lineage long ago. 

Finding evidence of the same mechanism in species as distantly related as sharks and chickens provides evidence that it is integral to many groups of animals and is genetically encoded throughout all vertebrate ancestry’s. 

Scientists studied the small-spotted catshark at about 80 days post-fertilisation using RD modelling and gene expression analysis.

This is a CT scan of a catshark embryo 90 days after being fertilised. Tooth-like scales of sharks and chicken feathers are created by the same process and explained by legendary code-breaker Alan Turing’s theory of reaction-diffusion


Alan Turing (pictured) was a British mathematician best known for his work cracking the enigma code in the Second World War

Alan Turing was a British mathematician who was born June 23 1912. 

During the Second World War, the mathematician was pivotal in cracking the German Enigma codes, which gave Allied leaders vital information about the movement and intentions of Hitler’s forces.

Historians credit the work of Turing and his fellow codebreakers at Bletchley Park in Buckinghamshire with shortening the war by up to two years, saving countless lives.

Turing is also widely seen as the father of computer science and artificial intelligence.

In 1952 he was convicted for homosexual activity, which was illegal at the time. 

To avoid prison, Turing agreed to ‘chemical castration’ – hormonal treatment designed to reduce libido.

In 1954, aged 41, he died of cyanide poisoning. An inquest recorded a verdict of suicide, although his mother and others maintained that his death was accidental.

As well as physical and emotional damage, his conviction had led to the removal of his security clearance and meant he was no longer able to work for GCHQ, the successor to the Government Code and Cypher School, based at Bletchley Park. 

He received a Royal pardon posthumously in 2014, only the fourth to be issued since the end of the Second World War.  

It was requested by Justice Secretary Chris Grayling, who described Turing as a national hero who fell foul of the law because of his sexuality. 


This showed evidence of dorsal denticle rows acting as ‘initiator’ rows, triggering the patterning of the surrounding tooth-like skin.

When compared with β-catenin (β-cat), an early regulator of chick epithelial placode signalling, in the birds they saw a similarity between the two animals.  

The same model was then applied to two other fish: the thornback skate and the little skate.

It is believed that this provided the development of the evolutionary advantageous drag reduction and armour. 

Dr Fraser added: ‘We teamed up with a mathematician to figure out what the pattern is and whether we can model it.

‘We found that shark skin denticles are precisely patterned through a set of equations that Alan Turing – the mathematician, computer scientist and the code breaker – came up with.

‘These equations describe how certain chemicals interact during animal development and we found that these equations explain the patterning of these units.’

The researchers also showed how tweaking the inputs of Turing’s system can create a diverse range of scale patterns. 

They believe the natural variety in this system could explain the scales in shark and ray species alive today.  

Rory Cooper, a PhD student at Sheffield University, said: ‘Sharks belong to an ancient vertebrate group, long separated from most other jawed vertebrates.

‘Studying their development gives us an idea of what skin structures may have looked like early in vertebrate evolution.

‘We wanted to learn about the developmental processes that control how these diverse structures are patterned, and therefore the processes which facilitate their various functions.’

This scanning electron microscopy image of a catfish hatchling’s scales. The findings of the study help explain how the scales of a shark evolved to reduce drag and be more energy efficient while swimming

Scientists used a combination of techniques, including reaction-diffusion modelling, to create a simulation based on Turing’s equations. 

Mr Cooper added: ‘Scientists and engineers have been trying to create shark-skin inspired materials to reduce drag and increase efficiency during locomotion, of both people and vehicles, for many years.

‘Our findings help us to understand how shark scales are patterned, which is essential for enabling their function in drag reduction.

‘Therefore, this research helps us to understand how these drag reductive properties first arose in sharks, and how they change between different species.’

He said patterning is an important aspect that contributes to achieving drag reduction in certain shark species. Another is the shape of individual scales.

The researchers now want to examine the developmental processes which underlie the variation of shape both within and between different shark species.

Mr Cooper added: ‘Understanding how both these factors contribute towards drag reduction will hopefully lead towards the production of improved, widely applicable shark-inspired materials capable of reducing drag and saving energy.’

Source: Read Full Article