SIGNS OF LIFE

Pollack (former dean of Columbia College and colleague of James D. Watson) takes the popular metaphor of DNA as language—and really runs with it. Pollack's thesis is that DNA, like language, is rich in multiple meanings, equipped with homonyms and synonyms. Furthermore, the genetic text should be seen in a historical context—some parts are archaic; others reflect more recent changes, the whole indicating where we came from as well as the diversity of the species today: The current effort to map and sequence the human genome constitutes only one sample of a text that varies from person to person. Pollack begins by explaining how a cell ``reads'' genetic text, taking us through the process of protein-binding to the regulatory sequences informing the actual gene. These initiate the instruction: ``Start here now.'' What follows is a gene ``sentence'' that says, ``Do this to that.'' But between the order and the execution come the myriad steps of unzipping the double helix; transcribing the DNA to messenger RNA; moving it to the body of the cell; and using the cell's machinery to translate the message into the production of a protein that executes the order. So much for the straightforward science-writing here: What Pollack also offers is a metatext—a commentary on how important it is for science and society to celebrate the diversity of the species and to avoid the Faustian trap of editing genetic texts in ways that would amount to a new eugenics. He has much to say about health-care reform, genetic testing, in-vitro fertilization, and the patenting of genes. Finally, he proposes a new paradigm: the model of biology as an exact science of atoms and molecules must be replaced by the recognition that we'll never be able to predict how genes combine to produce human behavior—a biological uncertainty principle. Cautionary and sober words that can well and truly inform current social, political, and scientific debates.