Natural Genome Remodeling

Stephen L. Talbott

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This article was written as a rather more technical (but still quite readable) “sidebar” to “Evolution and the Illusion of Randomness”, and can best be read in conjunction with that essay. Both pieces are part of a work in progress and may be subject to continual revision. Original publication: November 10, 2011. Date of last revision: November 25, 2011. Copyright 2011 The Nature Institute. All rights reserved. You may freely redistribute this article for noncommercial purposes only.

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In her 1983 Nobel address, geneticist Barbara McClintock cited various ways an organism responds to stress by, among other things, altering its own genome. “Some sensing mechanism must be present in these instances to alert the cell to imminent danger”, she said, adding that “a goal for the future would be to determine the extent of knowledge the cell has of itself, and how it utilizes this knowledge in a ‘thoughtful’ manner when challenged” (McClintock 1983). Subsequent research has shown how far-seeing she was.

It is now indisputable that genomic change of all sorts is rooted in the remarkable “expertise” of the organism as a whole. By means of endlessly complex and interweaving processes, the organism sees to the replication of chromosomes in dividing cells, maintains surveillance for all sorts of damage, and repairs or alters damage when it occurs — all with an intricacy and subtlety of well-gauged action that far exceeds, at the molecular level, what the most skillful surgeon accomplishes at the tissue level. But it’s not just a matter of preserving a fixed DNA