An important question is how bilateral symmetry is "implemented"; what developmental-genetic mechamisms cause the two sides to develop in sync? Are there some feedback mechanisms that keep one side from getting too far ahead of the other? It might be interesting to find out if there is some simple reaction-diffusion mechanism that can help maintain such symmetry, as there is for spots and stripes and other color patterns.
An interesting symmetry-generating mechanism was recently discovered; there is an article about it in a recent
Nature magazine. It's about how plants grow and what effects produce the positioning of their leaves on their stems.
A new leaf is induced by the growth hormone auxin acting on the side of the growing stem tip; this auxin comes from further back in the stem. However, existing leaves soak up auxin, producing auxin shadows in front of them, forcing the next leaves to be offset from their angle in the stem.
CBMGNCBINature - Not FoundNature Press Release for 20 November Issue
[This message has been edited by lpetrich, 11-29-2003]
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