Publisher: Little, Brown and Company
Publication date: 7/17/2012
Mendel’s pea plants and Watson and Crick’s double helix are only part of the fascinating story of DNA.
Following the New York Times bestselling debut of The Disappearing Spoon, author Sam Kean persuades us to peer further into the science of genetics in his newly released book, The Violinist’s Thumb And Other Lost Tales of Love, War, and Genius, as Written by Our Genetic Code.
Connecting the narrative of DNA to history and culture, the unconventional author writes about the first discoveries in genetics as well as the latest explorations into gene expression. According to Kean, geneticists actually talk about their work with terms lifted from the study of languages.
“Genetics even has grammar and syntax—rules for combining amino acid words and clauses into protein sentences that cells can read. Genetic grammar and syntax outline the rules for how a cell should fold a chain of amino acids into a working protein.”
The Violinist’s Thumb includes provocative stories of the men and women who received timely accolades for their work as well as those who withered in obscurity. The book delves into the infighting and controversy involved in pushing theories and earning citation. Kean even writes about the battle royale that threatened (or motivated) completion of the Human Genome Project.
Eccentric questions take us into each chapter of the ongoing story of the double helix. “Why did geneticists try to kill natural selection?” “How does nature read—and misread—DNA?” “How much human DNA is actually human?
An answer to the latter might bend our collective self-esteem only slightly. After all, humans share genes with insects, fish, reptiles and other mammals, including those that define our symmetry and alignment. Kean writes that human genes actually make up less than 2 percent of our total DNA. And it turns out that 8 percent of our genome, a quarter billion of our A-T-C-G base pairs, come from ancient virus genes.
“If DNA could do only the things we’ve seen so far—copy itself perfectly over and over, spin out RNA and proteins, withstand the damage of nuclear bombs, encode words and phrases, even whistle a few choice tunes—it would still stand out as an amazing molecule, one of the finest.”
In one of the more spirited chapters, Kean writes about epigenetics, or gene expression, that depends on subtle factors scientists are only now beginning to uncover.
DNA can be activated or inactivated by dotting A and T and C and G with methyl groups (CH3). Cells pass on these methyl patterns to daughter cells when they divide.
Is there evidence that expressed or silenced changes in one generation’s DNA can live on in descendants? Kean cites Överkalix, an isolated farming community, where environmental factors like food shortages were shown to predispose a pregnant woman’s child to schizophrenia or diabetes.
Swedish scientists also found, surprisingly, that epigenetic effects could persist through multiple generations. They observed a strong link between a child’s long-term health and his father’s and grandfather’s diets.
Humans accumulate more of these epigenetic changes as we age, which might explain why identical twins ultimately express different traits despite sharing identical DNA.
How genes are turned on and off, or our epigenome, may be the ultimate oracle of human adaptation and trait inheritance.
The Violinist’s Thumb by Sam Kean is a highly worthwhile read that unravels the secrets of DNA from an idiosyncratic perspective of history, science and culture.
Category: Nonfiction, Biology