I should be quiet because this is not my area. But the evo-devo people around me seem very often to say that, in the domain of large multicellular organisms, much of the change between species comes from altering regulatory pathways and systems, not generally from altering (numbers of) genes, or the overt things that genes code for.
I assume that a valid way to put some of these questions would be to suppose that adaptation to environments, filtered through the complexity and pre-commitments that constitute development, can be carried on structures of many kinds. The algorithmic complexity of regulation or response may not be easily tracked by numbers of genes, to the extent that more "structural" adaptations such as catalysts or transporters are. We then wonder what determines the apportioning of the information representations that constitute adaptation, or of control functions. Why some adaptations through duplication, divergence, and specialization of genes. Why other adaptation through changing the combinatorics with which regulatory proteins respond to signals or determine expression levels? Why some controls through protein regulators, other controls through small RNA regulators? Perhaps other controls through epigenetic modifications of either DNA or its structuring proteins. Why some adaptation through changing "hard-wired" internal representations of the environment, and other adaptation implicit in algorithms for responding to environmental states as signals? I think these are ways of putting the questions that allow us to look for characteristics of the environment and of the material an organism has available to build with, which can acknowledge evidence like gene counts, but not pre-interpret it (?). Eric ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
