Abstract

“Evolvability,” writes Evelyn Fox Keller, “refers to the capacity to generate any kind of heritable phenotypic variation upon which selection can act” . Whether one considers genes or organisms, the potential to adapt and evolve, to respond flexibly to a changing environment, is now recognized by many biologists as itself a trait actively favored by natural selection. Keller correctly presents this idea as an antidote to an old notion of genetic stability. She seems not to appreciate how well it applies to her own subject.The Century of the Gene is Keller's latest collection of linked essays, six tidy, intelligent shovelfuls from her ongoing effort to undermine the claims of mainstream molecular biology and to substitute from the scientific margins an alternative interpretation. This project stems from her philosophical biography of the geneticist Barbara McClintock, published in 1983. In her Nobel speech, also from 1983, McClintock wrote of the genome as a dynamic “sensitive organ of the cell,” responsive, flexible, and interacting with the environment. For half a century, McClintock had railed at biologists that genes must be studied not as autonomous, independently acting units but rather as parts of an exquisite whole, acting in concert. Keller celebrated this in McClintock's work, though many have read Keller as applying to this view of nature a gloss of feminism that McClintock rejected. More recently, among other projects, Keller has criticized the “master molecule” concept in biology, examined the use of metaphor in science, and celebrated Christiane Nüsslein‐Vollhard's studies in developmental biology. Through it all, she maintains a fascination with gender and with language as shapers of scientific thought.Here Keller explores what she sees as the divergent histories of studies of genes and use of the term “gene.” While scientists continue to talk of genes much as they have done for a century now—as stable, discrete units directing the activities of the cell and the development of the organism—the molecular biology of the last forty years has seen a breaking down of the boundaries of the gene, physically, chemically, and physiologically. Keller begins by attacking the notion of genetic stability—whence the introductory quotation about evolvability. Next she explores the idea of genetic regulation, the fact that genes do not make anything, nor do they literally control anything. The molecular biologist's version of the chicken‐and‐egg problem is: Which comes first—proteins or genes? Proteins read the DNA that provides the instructions to make more proteins. Keller argues for chickens.The most important idea in the book is Keller's distinction between a developmental program and a genetic program. The former is a sequence of ontological steps in the life of an organism; it does not presuppose that all steps in the program are encoded in genes or that all steps are determined prior to the beginning of development. Developmental programs may be derived empirically, independently of genetic analysis. In contrast, the genetic program is a more recent idea that does locate the program instructions in the nucleus in the fertilized egg. For Keller, genetic programs carry implications of determinism, a restriction of vision in our attempts to understand nature.The term “gene,” Keller concludes, has outlived its utility. Molecular biologists no longer work with anything so discrete as genes. Their own data, she argues, show that genes and genomes are flexible, modular, and interactive. Keller wishes for, but does not offer, a new term or set of terms that would better reflect current understanding of genetics and development.If biologists have shown that the gene concept is outmoded, why don't they know it? Keller's answer is that the biologists have not yet recognized the implications of their own results; their language lags behind their knowledge. Eventually, she believes, either they will drop the term “gene” or biology must suffocate in its shell. Yet the changes she describes have been under way for decades and biology shows no signs of slowing. Keller recognizes this, and in the conclusion she briefly acknowledges the obvious solution to the conundrum: that biology continues to grow because of, not despite, this linguistic flexibility. This important idea deserves fuller treatment.As with the gene in nature, so with the word “gene” in the scientific lexicon: its very evolvability is selected for, a crucial trait that ensures its survival