Slashdot Mirror

← Back to Stories (view on slashdot.org)

Turing Equation Explains how Leopard Spots Develop

Posted by ryuzaki0 on from the spotty-research dept.

BilZ0r writes "A slight modification of an equation developed by Alan Turing in 1952 has been used to show how the patterns of big cats change from kitten to adult markings. Sy-Sang Liaw of National Chung-Hsing University in Taichung, Taiwan, and colleagues set out to replicate these patterns using Turing's equations. But they found they had to do more than just tweak the parameters of the reaction-diffusion equation. Instead they had to assume two stages of spot growth with different rules: the first to get the baby cats their spots, and the second to create the final configurations. It took them a year to find a final solution."

9 of 109 comments (clear)

  1. Not OS X 10.5? by nlogax · · Score: 5, Funny

    Damn, i thought "Spots" was some sweet new feature in OS X Leopard.

  2. Turing test by Anonymous Coward · · Score: 5, Funny

    So how many questions were the leopard spots able to answer?

    Ohwait...

  3. New Adage by DumbSwede · · Score: 4, Funny

    ... no more than a Leopard can change his Turing Equations

    --
    Letter To Iran
  4. Tweaking parameters... by posterlogo · · Score: 5, Interesting

    This work is pretty interesting. My concern with complex mathematical models has always been that nearly any phenomena can be perfectly described given enough variables -- pretty much any curve, any pattern, any shape. In biology, when we try to fit models to data, we have to be very careful not to just keep trying to curve fit with more and more complex equations, because in the end we will be left with something that is not biologically very descriptive -- it leaves us with little understanding of the underlying biology. So when I hear these guys had to tweak parameters to make the reaction-diffusion equation fit the data, I am left wondering what biological factors those extra parameters are supposed to define? The original set of equations was meant to model a system with multiple morphogens that diffuse in two dimensions. When they act upon (or are acted upon) appropriate receptors, a particular "phenotype" emerges at that location. I did RTFA, but it doesn't actually say much about these things -- just makes up a dumb analogy with missionaries and cannibals in competition.

    1. Re:Tweaking parameters... by QuantumFTL · · Score: 4, Informative

      These types of nonlinear differential equations are usually very simple in form, and, most importantly, very local, as that is how most biological interaction is mediated. The parameter tweaking should not be considered too alarming when one considers that the number of biological parameters, in the sense of genetic material, involves thousands of degrees of freedom.

      A short (but good) web site about this can be found here. The interpretation of these formulas is fairly trivial, as they describe a diffusion process (common in all biological systems) with a somewhat more complex reactive process, which could be mediated through all kinds of channels.

      This is not akin to fitting a polynomial to the shape of a bone and calling that a "model" - there are obvious interpretations which correspond to very well known processes.

  5. The point is, you never know. by Elemenope · · Score: 5, Insightful

    Some researchers dicking around with orange molds accidentally discovered this little thing called PENICLLIN. Some Swiss mountain hiker got irritated with little seeds that kept sticking to his clothes, which upon further inspection led to the invention of VELCRO.

    On the other hand, researchers trying to solve a critical rubber shortage during World War II came up with an earth-shattering invention: SILLY PUTTY.

    Point is, you just never know. ;)

    --
    All the techniques ever used to make men moral have been themselves thoroughly immoral... (Nietzsche)
    1. Re:The point is, you never know. by Elemenope · · Score: 4, Informative

      anyhow, i believe you ment bread mold, not orange mold.

      Penicillium is a genus of what are called 'bread molds' which grow, eponymously, on most yeasted breads. However, they also have a strong affinity for orange rind, and oranges make a nearly ideal culture medium for its growth. Penicillin's antibacteriological properties were discovered in a lab when an orange was accidentally exposed to penicillium and then left in contact with a bacteria culture. Hence, for the story about serendipity and science, its affinity for oranges was more pertinent. Oddly enough, this genus provdes us with some of the molds that make some of the tastiest cheese around (esp. Gorgonzola).

      i know the best place to store rubber, place it skin tight on hot girls :D

      I, too, like rubber and girls. ;)

      --
      All the techniques ever used to make men moral have been themselves thoroughly immoral... (Nietzsche)
  6. Re:Leopard spots, snail shells, and Leonardo of Pi by ceoyoyo · · Score: 4, Funny

    I really hope you don't think freckles on, or redheads in general are boring. They're nothing like leopards either.

  7. Re:Extracting Sunlight from Cucumbers by Pseudonym · · Score: 4, Insightful

    And if you're an animation TD who has been assigned the task of creating a huge school of fish, each one of which should look different and yet still look like the right kind of fish, you'll be glad that someone has studied the problem of how to model animal markings.

    No, this is not hypothetical. It's real, and it's done today.

    --
    sub f{($f)=@_;print"$f(q{$f});";}f(q{sub f{($f)=@_;print"$f(q{$f});";}f});