Reading Genes

In his new book author Sam Kean switches from the periodic table to DNA.

By Thomas R. Tritton | May 5, 2013
Der Geiger Nicolo Paganini

Der Geiger Nicolò Paganini, Georg Friedrich Kersting. Oil on canvas, ca. 1831.

Sam Kean. The Violinist’s Thumb: And Other Lost Tales of Love, War, and Genius, as Written by Our Genetic Code. New York: Little, Brown, 2012. 416 pp. $25.99.

A new book by Sam Kean will be eagerly anticipated by all those who adore good writing about science. His first effort—The Disappearing Spoon (reviewed in Chemical Heritage, Spring 2011, p. 44)—was a thoroughly enjoyable romp through the people and peccadilloes that underlie chemistry’s iconic periodic table of the elements. The Violinist’s Thumb moves up in atomic scale from elements to molecules and takes on a very large one: deoxyribonucleic acid. The subject is timely and reminds one of the now legendary single word of career advice given to Ben (played by Dustin Hoffman) in the 1960s film The Graduate—“plastics.” Surely in the 21st century that one word summarizing unlimited opportunity would be “DNA.”

Kean delivers on the promise of another winning book. In order for the DNA story to be complete he necessarily rehashes material already thoroughly covered by others: Gregor Mendel’s pea-pod experiments; the discovery by Friedrich Meischer that nucleic acid, not protein, is the genetic material; James Watson and Francis Crick’s elucidation of DNA’s double-helical structure; the central dogma of molecular biology (DNA begets RNA begets protein); and Barbara McClintock’s jumping genes. The chapter on the race to sequence the awesomely gigantic human genome is also familiar, but Kean’s prose brings to life the glories and vainglories of Watson, Francis Collins, and Craig Venter as they goaded, competed, complained, and eventually accomplished the goal of the largest scientific project in history.

Kean employs a somewhat unusual structure: each chapter is a question about some aspect of DNA, which makes the book read more like a series of individual essays unconnected by a unifying argument, but does provide a general thread stitching together wonderfully illuminating anecdotes with clear language free of jargon. Because of this structure some of the chapters work better than others. The long section on Albert Einstein’s brain size, for example, and the account of Thomas Jefferson’s dalliance with Sally Hemings, while colorful, are only distantly connected to the DNA theme. And the chapter question entitled “Why Don’t Humans Have More Genes Than Other Species?” never gets answered.

Most of the material is both enlightening and entertaining. The description of outbreeding experiments (mating a male and female of different species) is appealing in its bizarreness, right down to the photograph of a “zonkey” (half zebra, half donkey). Luckily, we don’t know whether humans and chimps can successfully copulate, although Kean points out that one theory of evolution suggests this union was necessary between ancestors in each line to produce the modern, genetically diverse human that we all know and cherish.

Reading Genes_0.jpg

Portrait of Niccolò Paganini by Edwin Landseer.

Royal Academy of Music, London

Humor refreshes the writing with great regularity. Right away Kean confesses that his parents were named Gene and Jean, and thus it was irreversibly programmed into his inheritance that he would be compelled to write a book about genes. He turns phrases cleverly, as in discussing the legendary proclivity of Genghis Khan to impregnate large numbers of women: “Asia is littered with his litters today.” And if your sense of humor tends toward the gross you’ll enjoy the descriptions of one William Buckland of Oxford, who dined on every imaginable form of animal flesh—and even some unimaginable ones.

Readers smitten with curiosity about medical history will enjoy the multiple narratives on retrospective diagnosis—attempting to determine what health maladies befell famous people of the past. At some level this exercise is futile because clinical speculations based on secondhand information can rarely be proven. Speculations are hard to repress, however, and one such inspires the title of the book: Niccolò Paganini. Acclaimed by many as the greatest violin virtuoso of all time, Paganini was possessed of exceptionally strong and hyperflexible fingers. This condition might be explained by years of practice and exercise or perhaps just as the extreme end of the normal human bell curve. Kean prefers the retrogenetic conjecture that Paganini suffered from Ehlers-Danlos syndrome (EDS). Those so afflicted cannot make adequate collagen that gives rigidity to joints. Since modern musicians (and dancers) have a higher rate of EDS than normal, it is possible that Paganini’s freakishly unusual joints suggest that he did as well. It can’t be proven, of course, but it can’t be disproven either, and does lend itself to an irresistibly enticing book title.

One quibble about scientific accuracy: A couple of times in the narrative Kean mistakes vitamin A as a transcription factor—a substance that clamps onto genes to regulate their expression. The picky scientist will note that vitamin A actually binds not to DNA but to the retinoic acid receptor, which in turn is the actual transcription factor that binds to and controls gene expression. To his credit, though, the book takes on some scientifically and emotionally challenging subjects (e.g., the possibility of a genetic basis for race, prospects of a gay gene, the role of nature and nurture in human intelligence) with high precision, sensitivity, and his usual graceful humor.

I learned a lot reading this book. It bogs down in places, but Kean has a true knack for waking the reader with a catchy phrase or offbeat observation. If you care at all about DNA—its history, its impact on contemporary society, and its implications for the future—this volume is worth your time.