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© 2000 America Inc. ¥ http://medicine.nature.com BOOK REVIEW

mined set of instructions. But the same the space around it, and more explicit con- The Triple Helix: genes have different products in different struction such as building a nest); its per- environments. sequence does ceptual abilities that determine which Gene, not fully determine structure and environmental signals it picks up; and its thus function; instead, is with other . and Environment influenced by a diverse set of entities in the The last part of the book asks how we cell1. For example, a protein can take on a should proceed. Unlike machines, which toxic or non-toxic form depending on the can be separated easily into independent By Richard C. Lewontin shape of pre-existing . The out- components, any piece of a biological Harvard University Press, 192 pp, $22.95 come of development, what particular or- system we choose to study is likely to be ISBN: 0674001591, 2000 ganism develops, is affected by noise from causally linked to parts not studied. random molecular events within cells, and Lewontin’s advice is to look carefully at REVIEWED BY DEBORAH M. GORDON by the environment in which the organism the strands of the causal web that are Department of Biological Sciences grows. How come to vary is the outside the spotlight. He argues vehe- Stanford University, Stanford, California USA starting point for the study of natural selec- mently against “obscurantist holism”, tion, because without variation, there is the attempt to understand a system with- Soon we will know the sequence of the nothing to select. Lewontin’s best known out examining the operation of its , or some ’ work in , studying evo- components. He has made many contri- , anyway – and then what? The se- lution in fruit flies, led to new techniques butions to the mathematical theory of quence alone will not tell us which parts for examining variation in . evolutionary change, but he is not opti- function as genes, much less what those A naïve view of equates func- mistic that new theoretical advances will

.com genes do. We are deluged by new knowl- tion with adaptation; if we can identify a provide general laws applicable to all edge in and molecular but, this function of a trait, that function must be complex biological systems. To those

.nature book by evolutionary biologist Richard why put it there. One of ready to escape the old ideas, Lewontin Lewontin argues, we know much less than Lewontin’s most famous conceptual pa- counsels patience and empiricism. His we would like to believe we do. The Triple pers (with S J Gould) (ref. 2) points out the examples draw on the relation of form Helix stands back to look at the whole of foolishness of this assumption. A trait and function: how cells in a developing biology as we practice it at the turn of the might be irrelevant to natural selection, or organism make body parts of a particular century. A key question re- it might be an inevitable shape, how transforms http://medicine ¥

mains in development and consequence of another DNA sequences into particular gene evolution: how to explain trait under selection, or it products, how minor map variation. Genes may ac- might actually be detri- onto small variations among , count for why you are dif- mental, in which case nat- and in a more abstract notion of “shape ferent from a chimpanzee, ural selection might be and form,” how organisms change their but not for why you are dif- working to eliminate it. environments as they evolve, thus ferent from me. Are we Facile adaptive explana- changing the conditions of evolution. headed toward the an- tions for human behavior The dust jacket says this is “vintage swers? John Maynard are one weakness of socio- Lewontin” but it would be more accurately 2000 Nature America Inc. Keynes once wrote, “The biology and its offshoots, described as distilled Lewontin, concen- © difficulty lies, not so much which Lewontin has vigor- trating a career’s worth of thinking about in developing new ideas, as ously opposed; there is lit- genetics and evolution into a small, elegant in escaping from the old tle evidence to link natural and powerful book. It will stimulate pas- ones.” This book takes on selection with the observa- sionate discussion in a journal club; bring that difficult task for biol- tion that some people are relief to students who sense that the text- ogy. smarter, richer or happier books aren’t telling the whole story; annoy Lewontin argues that we have come up than others. If ad hoc accounts of adapta- anyone who promotes simple generaliza- against the constraints of the reigning tion are inadequate, how then can we un- tions about development or evolution; and metaphors in biology. Metaphors are nec- derstand natural selection? Lewontin inspire new ideas. essary because we cannot see most of the discusses the Darwinian metaphor of the things we study, but when we believe the organism adapting to an environment that 1. Feldman, D. E. & J. Frydman. Protein folding in vivo: the importance of molecular chaperones. Current Opinion thing actually is the metaphor, we are in is independent of it. He points out that en- Struct Biol. 10, 26-33 (2000). trouble. We speak of genes as a blueprint, vironments are in fact constructed by or- 2. Gould, S.J. & Lewontin, R.C. The spandrels of San Marco and the Panglossian paradigm: a critique of the program or , and so come to see devel- ganisms, through the organism’s activities adaptationist programme. Proc. Roy. Soc. Lond. B. Biol. opment as the unfolding of a predeter- (where it goes, its physiological effects on Sci. 205, 581-598 (1979).

12052 NATURE MEDICINE • VOLUME 6 • NUMBER 11 • NOVEMBER 2000