On June 26, 2000, leaders of the Human Genome Project and the biotechnology company Celera Genomics announced the much-anticipated completion of a draft of the human genome. This massive achievement of recording the entire genetic code for a human being represents the culmination of forty-seven years of research since James D. Watson and Francis Crick’s discovery of the structure of deoxyribonucleic acid (DNA). The revelation of this precise genetic information, however, marks a beginning not an ending. It promises to usher in a new age of medical genetic advances that will lead to new ways to prevent, diagnose, treat, and cure an estimated four thousand hereditary diseases and untold other illnesses that have a genetic component. In Genome: The Autobiography of a Species in 23 Chapters, Matt Ridley provides an excellent framework for understanding the ways in which genetic information can illuminate issues in such diverse areas as the evolution of life, the molecular nature of disease, the interaction between genetic and environmental influences, the politics of technology usage, and the influence of genetics on psychology. Ridley’s background as a student of science (he has a Ph.D. in zoology), a journalist, and a nonfiction writer combine to enable him to discuss such wide implications of the human genetic makeup in a manner that is at once engaging to those with a background in biology and highly educational to those without one.
Ridley asks the reader to think of the genome as a book written by the genome itself—hence, an autobiography. Eight hundred times as long as the Bible, this “document” can be found in almost every cell of the human body. It has a mere twenty-three chapters (the number of chromosomal pairs in the human genome), but each chapter contains several thousand stories (genes). There are paragraphs (exons), nonsensical advertisements (introns), words (codons), and letters (bases). Unlike other languages, this one has an alphabet of only four letters (A, C, G, and T, each standing for a different base), and a lexicon of three-letter words exclusively (TAC, GTA, ACT, and so on). Replication, the process by which genes copy themselves, is similar to photocopying, while the way genes make proteins is similar to reading, as codons are translated into amino acids. The benefits of understanding this language are manifold. There are no written records of the prehistoric past; researchers rely on anthropology, geology, and evolutionary biology to shed light on the origin and development of the human species. The human genome, however, is a written record of the species and to some extent of all life on this planet. It can tell the story of humanity’s ancestors from earliest times to the present and perhaps explain why human beings are the way they are.
Each chapter of Genome concentrates on genetic information from each of the twenty-three pairs of chromosomes. Ridley has carefully selected the genes that drive the content of each chapter and uses them as springboards for discussing a variety of issues. Many of these “stories” serve to illustrate the important biochemical and genetic principles by which genes function. Ridley describes some of the most well-studied genes that caught the attention of researchers because they can cause disease when mutated. He cautions the reader several times, however, that “genes are not there to cause diseases.” One such gene, found on chromosome 3 and therefore discussed in chapter 3, causes the rare disease alkaptonuria. Ridley uses it to show how mutations in genes that code for protein enzymes can lead to metabolic disorders. In a chapter entitled “Environment,” Ridley uses a gene that may be in part responsible for asthma to describe pleiotropy, or the multiple effects of one or more genes, and to explore the interplay of environmental influences with genetic information. He also takes a look at the fascinating role of infectious diseases such as cholera and malaria in shaping the distribution of genes in the ABO blood group in human populations. In chapter 20, Ridley tells a very mysterious tale of heredity. The story of the protease-resistance protein leads him to discuss Nobel Prize winners, cannibalism, “mad cow disease,” a rare genetic disorder called Creutzfeldt-Jakob disease, and the British politics of epidemiology. The key to the mystery turns out to be a “prion,” a protein whose mutant three-dimensional structure is capable of spreading disease.
Other genes allow Ridley opportunities to delve into complex issues in psychology. Ridley’s choice of a gene from chromosome 6 that may play a role in the determination of intelligence allows him to weigh in on the hotly debated question of nature versus nurture. In the chapter “Instinct,” he relates the function of a gene to the instinctual development of language. He also describes the dopamine...
(The entire section is 1992 words.)