Chance and necessity in cellular response to challenge

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Abstract
Mol Syst Biol. 3: 107 Living cells are enormously elaborate and exquisitely fine‐tuned molecular machines, and the way they respond to changes in the environment is precisely determined by the iron logic of adaptation. Or so we would like to believe should we stick to the traditional adaptationist paradigm of neo‐Darwinism (Dobzhansky 1951; Mayr 1963). Of course, the foundations of neo‐Darwinism have been shaken a long time ago by the demonstration that many, if not most, of the mutations that are fixed in populations are neutral (Kimura 1983; Nei 2005), although these neutral changes provide the raw material for subsequent selection (Wagner 2005). However, what about the actual physiology, specifically, the cellular response to environmental challenge; is it primarily adaptive or is there a substantial neutral component even at this level of biology? In a study currently published in Molecular Systems Biology , Stern et al (2007) offer some of the most compelling evidence so far that the transcriptional response of yeast to a severe challenge is dominated by stochastic noise. In the last few years, an increasing number of studies examined the global transcriptional response of diverse cells to various kinds of perturbations. Although the often considerable and uncertain amount of technical noise in the microarray data muddies the …