Speciation occurs, yes. But within very definite (although hard to pin down) limits. There is a growing body of evidence that the variability that gives rise to speciation was pre-programmed into organisms. Have you read Chris Ashcraft's Genetic Variability by Design? This explains a lot about Homologous Recombination and it's role in adapting organisms to their environment. Mutations (the traditional definition of the word, i.e. 'copying mistake') do not suffice as a mechanism for 'progressive' evolution (to use Muller the Fruit Fly Guy's term). Mutations, taken as a whole, are destructive ... not constructive. Change occurs, yes. But the evidence is mounting that the constructive change--bigger beaks, darker colors, etc--happens under tight cellular control. Here's an excerpt from Ashcraft's article ...This is Darwin's proposed mechanism for the Origin of Species:
Organisms are replicated with modification; those modifications that happen to be able to replicate more are replicated more.
It's so simple, it fits into a single sentence. And it works. You can even set up toy systems on a computer, and see it in action - speciation occurring before your very eyes.It is now widely recognized that genetic editions through HR [Homologous Recombination] are part of a highly coordinated process involving a cascade of specific macromolecule interactions,7 and controlled by highly organized regulatory systems.8 In particular, the induction of recombination during meiosis is reliant upon several genes, and is regulated by a complex network of cell signaling mechanisms.9
7 Cascades of Non-covalent Protein-protein and Protein-DNA Interactions for Homologous DNA Recombination. Takehiko Shibata. RIKEN Review 46:24-28 (2002)
8 Hierarchic Regulation of Recombination. Kunihiro Ohta. RIKEN Review 41:28-29 (2001)
9 Homologous genetic recombination as an intrinsic dynamic property of a DNA structure induced by RecA/Rad51-family proteins: a possible advantage of DNA over RNA as genomic material. Shibata, T., Nishinaka, et al. Proc. Natl. Acad. Sci. U.S.A. 98(15):8425-8432 (2001)
http://www.nwcreation.net/articles/r...ionreview.html


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