Mar 24, 2014 I Mysterious Universe

Alan Turing’s Model Confirmed: Who Knew he was a Biologist?

When you think of the renowned, yet often overlooked, genius of early computing, Alan Turing, I’m betting you imagine code breaking machines, complex mathematical formulas and maybe Artificial Intelligence.  Few of you, I think, would immediately think of biology.  Even fewer yet would think of morphogenesis.

What the hell is morphogenesis, you ask?  That’s a great question!  I’m so glad you asked.

When a cell is created – one of the fundamental building blocks of all biological material – how does it know whether it is to become a brain cell, or a blood cell, or a photosynthetic cell in the broad leaf of a plant?  It’s kind of complicated, but it essentially boils down to its shape.  You see, when cells undergo sorting, a process known as morphogenesis, the structure of their cell membranes begin to change, causing tissue elongation, thinning and folding by way of the introduction and interaction of certain chemicals.  Those changes affect the way individual cells connect with and interact with neighbouring cells.  They generally want to maximise the surface area of contact between them, so as morphogenesis takes place, the different shapes (for lack of a better word) of the cells cause them to group together in distinct types.  As they say, birds of a feather, flock together.


You can see, I hope, how that begins the process of differentiating one type of cell from another, and allowing complex organisms to be constructed from these basic building blocks.

Morphogenesis, along with the concepts of cell growth and cellular differentiation, make up the fundamental aspects of developmental biology.

So what does that have to do with Alan Turing?  Well, that’s another great question…you’re on a roll!

The foundation of the theory was originally formulated in 1917 by the pioneering mathematical biologist D’Arcy Wentworth Thompson, who used specialised formulas to account for naturally occurring patterns, like the spirals in snail shells.  The theory was drastically furthered by Turing in 1952, however, when he correctly predicted the diffusion of chemical signals, where one chemical activates growth, and another deactivates it, and thus sets up developmental patterns.

Through his mathematical model, Turing predicted six different patterns of morphological development, and while the science is certainly interesting, it is quite complex, so feel free to look into it on your own if you feel so inclined.  What’s important here is that Turing was the first to accurately describe the process and to predict the mechanism of development.  Of course, Alan Turing wasn’t a biologist.  He was a mathematician.  A wonderfully gifted mathematician, whose theorems have founded and advanced computer science to a degree that would otherwise have been impossible.

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An example of morphogenesis, demonstrated in embryonic cells.

What’s particularly fascinating is that he, and Thompson before him, were the first to apply higher order mathematics to biological systems, an approach that has yielded some of the most spectacular revelations regarding the geometry of nature.  But Turing’s model of morphogenesis had, until recently, gone untested, so while it was interesting as a theoretical framework, it had yet to be confirmed as true.

All that changed March 10, 2014, when scientists at Brandeis University and the University of Pittsburgh published a paper in the Proceedings of the National Academy of Sciences that serves to provide that confirmation.

Dr. Seth Fraden and Dr. G. Bard Ermentrout used synthetic cell-like structures and computational tools to analyse the process in laboratory, and were able to produce all six of the exact patterns predicted by Turing, plus one he apparently missed.  The explanatory power of Turing’s model is impressive.  It provides key insights into a wide range of natural phenomenon, such as the pigmentation of seashells, to the shape of flower petals and leaves, to the geometric patterns produced in the perception of people experiencing psychedelic-drug-induced hallucinations.[1]

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Alan Turing (1912-1954)

This confirmation comes 60 years after Turing’s suicide; the tragic outcome of his lifelong battle with bigotry and discrimination.  As seems to be the popular thing to celebrate these days, it is now relatively well known that the father of modern computers was both gay and an atheist.  Two things that made him an outcast in his day.  It seems oddly ironic that the contributions of a social pariah – a man who suffered the scorn of the church, his government and his peers – should yield such a massive impact on our understanding and enjoyment of the world.  In 2009, and at the behest of a petition that was overwhelmingly supported by the public, he was offered a posthumous pardon for his conviction of gross indecency, stemming from what some believe was a conspiratorial plot to oust him as a homosexual, and he received a formal apology from the British Government.  Though this late reconciliation did nothing to undo the damage of his sentence, which was to undergo libido reduction through the administration of various medications, which ultimately left him impotent and with gynecomastia.

Following Turing’s morphogenesis predictions, the next major breakthrough in developmental biology came with Watson and Crick’s momentous discovery of DNA in 1953, just a year after Turing published his first and only paper on the topic, and mere months after his death.  It might be said that their work would not have progressed as it did, had Turing not provided his insights a year earlier.

Were it not for the brilliance of Alan Turing, computer science would be decades behind where it is now, and perhaps biological science would be stunted as well.  Turing’s story is inspiring and has been immortalised in film with the docu-drama Codebreaker and many books.  He has been honoured in death, as he should have been in life, and it seems that those who record history, in this case at least, have righted the wrong of our past prejudice.

[1] Nathan Tompkins, Ning Li, Camille Girabawe, Michael Heymann, G. Bard Ermentrout, Irving R. Epstein, and Seth Fraden. Testing Turing’s theory of morphogenesis in chemical cells PNAS 2014 : 1322005111v1-201322005.

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