To celebrate Darwin's Birthday, Science Magazine ran a special devoted to evolution. An article by Stern and Orgogozo entitled "Is Genetic Evolution Predictable?" presented a stunning break from neo-Darwinism.
The authors presented a convincing refutation of the "Blind Watch Maker" argument of Richard Dawkins. Quite the contrary, the "Watchmaker" had his eyes wide open.
Molecular Biology Trumps Darwin
The authors found that mutations cluster around certain “hot-spot genes,” also called regulatory genes, making evolution somewhat predictable. The authors were able to predict genome response to environmental stress. The most compelling case for this comes from parallel genetic evolution. They cite a number of example of similar genome changes in different species in response to environmental stress.
"Although mutations are thought to ocurr randomly in the genome, the distribution of mutations that cause biologic diversity appears to be highly non-random."
"Is genetic evolution predictable? Evolutionary developmental biologists have argued that, at least for morphological traits, the answer is a resounding yes. "
You can read Stern's earlier paper here.
References
http://www.molbio.princeton.edu/index.php?option=content&task=view&id=239
David L. Stern PhD
Evolutionary developmental biology
Our research addresses biological problems arising at the interface of evolution and development. How does development evolve on a short time scale, within and between closely related species, to generate phenotypic variation? What are the genetic mechanisms regulating polyphenisms and other dramatic life-history switches? We address these questions using genetic, molecular and developmental techniques. For studying the problem of variation we primarily work with the fruit fly Drosophila melanogaster and closely related species. We study polyphenisms in the pea aphid (Acyrthosiphon pisum).
We found that evolution at the Ubx locus contributes to a difference in this trait between Drosophila melanogaster and D. simulans and this difference appears to be due to evolution of cis-regulatory DNA. This is the first experimental demonstration that evolution of Hox gene patterning is responsible for an interspecific morphological difference.
This is the first experimental demonstration that evolution of Hox gene patterning is responsible for an interspecific morphological difference.
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=18616572
Evolution. 2008 September; 62(9): 2155–2177.
Society for the Study of Evolution.
The Loci of Evolution: How Predictable is Genetic Evolution?
David L Stern and Virginie Orgogozo
We also found that different spectra of evolutionarily relevant mutations segregate within populations and between species. Interspecific differences in morphology seem to be more often caused by cis-regulatory changes than intraspecific variation.
This result is not predicted by a traditional neo-Darwinian view of the contribution of intraspecific variation to interspecific differences.
Is genetic evolution predictable? Evolutionary developmental biologists have argued that, at least for morphological traits, the answer is a resounding yes.
Most mutations causing morphological variation are expected to reside in the cis-regulatory, rather than the coding, regions of developmental genes. This "cis-regulatory hypothesis" has recently come under attack. In this review, we first describe and critique the arguments that have been proposed in support of the cis-regulatory hypothesis.
We then test the empirical support for the cis-regulatory hypothesis with a comprehensive survey of mutations responsible for phenotypic evolution in multicellular organisms. Cis-regulatory mutations currently represent approximately 22% of 331 identified genetic changes although the number of cis-regulatory changes published annually is rapidly increasing. Above the species level, cis-regulatory mutations altering morphology are more common than coding changes. Also, above the species level cis-regulatory mutations predominate for genes not involved in terminal differentiation.
These patterns imply that the simple question "Do coding or cis-regulatory mutations cause more phenotypic evolution?" hides more interesting phenomena. Evolution in different kinds of populations and over different durations may result in selection of different kinds of mutations. Predicting the genetic basis of evolution requires a comprehensive synthesis of molecular developmental biology and population genetics.
