Portugese Water Dogs & Regulatory Genes

I have no clue what the Discovery special was on about. If they're referring to the well-known and well-documented fact that changes in regulatory genes can have a profound effect on phenotype (explaining dog breeds, for ex), I'm not sure what they mean by "changing the way we look at evolution". I did find an article that the special might have been based on: Genetic basis for systems of skeletal quantitative traits: Principal component analysis of the canid skeleton which showed that minor changes in regulatory genes (they studied the Portuguese water dog as an exemplar) can have significant effects on skeletal structure. From the abstract:

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Evolution of mammalian skeletal structure can be rapid and the changes profound, as illustrated by the morphological diversity of the domestic dog. Here we use principal component analysis of skeletal variation in a population of Portuguese Water Dogs to reveal systems of traits defining skeletal structures. This analysis classifies phenotypic variation into independent components that can be used to dissect genetic networks regulating complex biological systems. We show that unlinked quantitative trait loci associated with these principal components individually promote both correlations within structures (e.g., within the skull or among the limb bones) and inverse correlations between structures (e.g., skull vs. limb bones). These quantitative trait loci are consistent with regulatory genes that inhibit growth of some bones while enhancing growth of others. These systems of traits could explain the skeletal differences between divergent breeds such as Greyhounds and Pit Bulls, and even some of the skeletal transformations that characterize the evolution of hominids.

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However, all the article does is provide additional evidence for the "small changes can yield major effect" hypothesis. It also gives a nice quantitative way of measuring these changes. OTOH, I don't think it changes "the way we view evolution", except as noted.What it does do is provide even more ammunition to destroy the creationist "macroevolution-doesn't-exist-because-it-requires-X (insert really big number) -mutations-and-there-isn't-enough-time-in-the-universe" argument.

BumpChara: No comment?

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Not really, I had seen the show ... wondered what they meant when they said that it would cause a different perspective on evolution and asked the question. Was there something I should have said? :-)

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Nope, nothing specific. Just wondered if I'd answered your question or if you wanted more information. The observation was something of a contentious issue when it was first proposed, but now seems to be coming into wider acceptance. The problem was that it seemed to violate the adage "natura non facit saltum" ("nature doesn't make jumps"), which was the counter to Goldschmitt, among others. With our increased understanding of how regulatory genes work and their influence on development, it appears that - at least in some cases - nature can make jumps...[This message has been edited by Quetzal, 12-11-2002]