The Chemical Basis of Morphogenesis

Alan Turing

Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 237(641), pages 3772, August 1952

It is suggested that a system of chemical substances, called morphogens, reacting together and
diffusing through a tissue, is adequate to account for the main phenomena of morphogenesis.
Such a system, although it may originally be quite homogeneous, may later develop a pattern
or structure due to an instability of the homogeneous equilibrium, which is triggered off by
random disturbances. Such reaction-diffusion systems are considered in some detail in the case
of an isolated ring of cells, a mathematically convenient, though biolo:irall, unusual system.
The investigation is chiefly concerned with the onset of instability. It is faund that there are six essentially different forms which this may take. In the most interesting form stationary waves
appear on the ring. It is suggested that this might account, for instance, for the tentacle patterns on Hydra and for whorled leaves. A system of reactions and diffusion on a sphere is also considered. Such a system appears to account for gastrulation. Another reaction system in two
dimensions gives rise to patterns reminiscent of dappling. It is also suggested that stationary
waves in two dimensions could account for the phenomena of phyllotaxis.
The purpose of this paper is to discuss a possible mechanism by which the genes of a zygote
may determine the anatomical structure of the resulting organism. The theory does not make any
new hypotheses; it merely suggests that certain well-known physical laws are sufficient to account
for many of the facts. The full understanding of the paper requires a good knowledge of mathematics, some biology, and some elementary chemistry. Since readers cannot be expected to be
experts in all of these subjects, a number of elementary facts are explained, which can be found in
text-books, but whose omission would make the paper difficult reading. 

journal = {Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences},
author = {Turing, Alan},
title = {The Chemical Basis of Morphogenesis },
year = 1952,
pages = {37--72},
number = 641,
venue = {--},
month = {Aug},
volume = 237

Partita IVA: 01131710376 - Copyright © 2008-2022 APICe@DISI Research Group - PRIVACY