February 20, 2012
Evidence Discovered To Support Turing’s Morphogen Theory
A team of UK researchers claims to have put forth the first ever experimental evidence in support of a long-standing theory about how biological patterns such as a leopard's spots or a tiger's stripes are formed.
The study was the work of experts from King's College London, and according to a February 19 press release from the school, "The findings provide evidence to support a theory first suggested in the 1950s by famous code-breaker and mathematician Alan Turing," who championed the idea that "regular repeating patterns in biological systems are generated by a pair of morphogens that work together as an 'activator' and 'inhibitor'."
Their work "not only demonstrates a mechanism which is likely to be widely relevant in vertebrate development, but also provides confidence that chemicals called morphogens, which control these patterns, can be used in regenerative medicine to differentiate stem cells into tissue," the college added.
In order to test their theory, the King's College London researchers analyzed the development of regularly-spaced ridges that can be found in the mouths of mice.
By conducting experiments using embryos of the rodents, they were able to discover the pair of morphogens that work together to help determine where each of the ridges will be formed. Each chemical influenced the other, the university said, alternately activating or inhibiting production in order to control the creation of the ridge pattern on the roof of a mouse's mouth.
The morphogens involved in the process were identified by the scientists as Fibroblast Growth Factor (FGF) and Sonic Hedgehog (Shh), and by studying them, they learned that when each chemical's activity is increased or decreased, it affected the pattern of the ridges in the mouth in the same way that Turing's equations had predicted they would.
"For the first time the actual morphogens involved in this process have been identified and the team were able to see exactly the effects predicted by Turing's 60-year-old speculative theory," the college press release stated.
"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. 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," Dr. Jeremy Green from the Department of Craniofacial Development at King's Dental Institute added in a statement.
While Green admitted that the discovery was "not of great medical significance," he said that they are "extremely valuable" in validating Turing's theories from the 1950s. He also says that their discovery has made them confident that these morphogen chemicals could be used in the future to create regenerative medicine to heal or recreate structures and/or patterns when turning stem cells into other types of tissues.
The research was funded by the Medical Research Council and is published online in the journal Nature Genetics.
Turing, who was born on June 23, 1912 and would have turned 100 this year, has been referred to by some as the father of computer science and artificial intelligence. During World War II, he served as a member of the Government Code and Cypher School (GCCS) at Bletchley Park in the field of naval cryptanalysis.
Turing later went on to join the National Physical Laboratory, where he created one of the very first stored-program computer designs, in 1948 he assisted in the development of computers at Manchester University. His paper "The Chemical Basis of Morphogenesis," in which he first put forth his theory of pattern formation, was published by Philosophical Transactions of the Royal Society of London in August 1952.
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