Sunday, May 3, 2015


Sam Kean, The Violinist’s Thumb: And Other Lost Tales of Love, War and Genius, As Told By Our Genetic Code (Little, Brown and Company, 2012).

Available in hardcover, paperback, audible, and Kindle formats   

by Cam Addis

Popular science writer Sam Kean works the same magic with DNA in Violinist’s Thumb (2012) as he did with the elemental table in Disappearing Spoon (2010). In both cases, he explains science to a broad audience with flair and a dash of humor. The books cover not just science, but the very human stories of the scientists, as they struggle to get their theories heard and overcome turf wars and eccentricities competing with one another. Like other episodes in the history of science, they are slowly and messily trying to piece together an ongoing story that only seems obvious in retrospect, if at all. Female scientists like Sister Miriam Michael Stimson, Lynn Margulis and Barbara McKlintock failed to get their ideas accepted, only to be redeemed decades later. Their research showed how DNA is structured and how it instructs cells to go make organs and assemble them in the shape of a body. The stuff is so informative that, in the future, we may use DNA to study DNA rather than silicon computer transistors.

The Violinist’s Thumb: And Other Lost Tales of Love, War and Genius, As Told By Our Genetic Code is more than a history of DNA and its discovery; it’s an informal “big picture history” of mankind as told through DNA. It turns out that, aside from telling your cells how to be organs and a body, DNA records a history of our species, like “little monks in your cells.” Vestigial tail genes, for instance, are dormant or suppressed in humans but haven’t disappeared. There are little monks in every cell in our bodies, including millions in a humble booger you might extract from your nose. There’s enough DNA in your body to stretch from Pluto to the Sun and back if uncoiled. DNA is a sticky substance that could be thought of as the “language” in which the more conceptual “book” of genes is written in. Kean explains why evolutionary theory and genetics first exhibited a “remarkable degree of bitchiness” because natural selection “accounted for survival of the fittest, but not arrival of the fittest.” DNA bridged that gap and allowed the fields to synthesize. 

The book’s title comes from violinist Niccolò Paganini’s remarkably large and flexible hands, which contributed to his dexterity. Paganini was a rare classical musician who gained immortality as a performer rather than a composer. By performing in cemeteries, he fanned the flames of rumors that he’d struck a deal with the devil, but Paganini’s real secret was his “tarantular” hands. He could bend his thumb far enough behind his hand to touch his pinky, and was said to be able to play a thousand notes a minute.  He may have had Ehlers-Danlos syndrome, which prevents the formation of collagen – the fiber that gives ligaments and tendons their rigidity and strengthens bones. It’s difficult to tell what afflicted/aided famous people long after the fact, though the author tries his hand at diagnosing famous figures like Jefferson, Lincoln, Kennedy and Darwin, all of whom suffered from mysterious maladies (debilitating in Darwin’s case). 

As in Paganini’s case, it’s hard to classify genes as simply good or bad, because mutations are how we evolve. Microbes, too, can encourage or discourage species to reproduce. Viruses and bacteria transferred some of the coding into our DNA (viruses ~8%). Kean reminds readers that studying one’s own genetic traits doesn’t provide a certain glimpse into one’s fate. He worried about this since Parkinson’s disease runs in his family, but toward the end of the book he musters the courage to peek at the report and is relieved to see he doesn’t display the marker for Parkinson’s. However, even if he had, that wouldn’t mean he’d get it, so he chides himself for the irrationality of not wanting to look and for being so relieved after he did. All of us carry markers for many diseases we never contract. Regardless of what people inherit or experience, cells vary a lot, as the author illustrates detailing the medical history of Tsutomu Yamaguchi, a Mitsubishi employee who survived both the Hiroshima and Nagasaki attacks of 1945 and lived to old age because his cells repaired DNA well.  Whatever mutations he suffered were “silent,” occurred in unimportant stretches of DNA, or failed to disable key circuits.

The final chapters of the book cover the controversies surrounding the Human Genome Project, and genetic implications regarding race, gender and sexuality.  While it’s become fashionable in my own field of history to claim that race is purely sociological with no grounding in biology, Kean explains some overlap between geographic ethnicities and social racial constructs. Genetics, after all, dictates outward physical appearance, though that’s a tiny part of DNA. More importantly, ignoring race altogether could impede our study and treatment of ailments like cancer, diabetes and Crohn’s disease. In comparison to chimpanzees, though, humans don’t show much ethnic diversity, with the biggest variations among black populations in Sub-Saharan Africa. The rest of us (Whites, Asians, Hispanics, Middle Easterners, etc.) descend from African tribes that emigrated after the “Great Bottleneck,” an event that nearly wiped out humanity around seventy thousand years ago. DNA evidence confirms the bottleneck in human history, though it doesn’t provide any specific evidence concerning whether it was a singular catastrophe (like the Toba super-volcano in Indonesia) or spread out over thousands of years.

Kean explains how the million-year fling between humans and chimpanzees never converged into a new species -- not because human brains are bigger, but rather because chimp sperm is so much stronger and faster that humans weren’t able to impact the chimp population. For the same reason, Soviet attempts to discredit Christianity by breeding “humanzee” slave-soldiers also failed. The humanzee work of Soviets and the American Association for the Advancement of Atheism provoked the ire of the KKK, who wrote letters discouraging such “devil’s work.” In my opinion, this was perhaps the only time in its 150-year history that the Klan was ever on the right side of an issue.
Violinist’s Thumb sets straight some misconceptions surrounding human cloning. Nature already provides clones in the form of identical twins. Yet, identical twins grow increasingly different over time because their life experiences vary. The “memory cache” of our experiences goes a long way toward determining our character. The same would be even truer of artificial clones, which is why they are neither anything to fear nor worth pursuing in the first place.

Even after our core DNA sequencing is set, we can influence our DNA’s impact on a few subsequent generations through epigenetics, which impacts how cells access, read and use DNA. An example would be traumatic stress brought on by a pregnant woman surviving something like the 9/11 attacks. Such an event could transform the way cells talk to DNA in her children or grandchildren, “etching a memory” not in terms of a graphic, visual image of the event, but in making her offspring more prone to anxiety and stress. Most epigenetic footprints are erased, though, when sperm meets egg. Historians used to think of evolutionary pioneer Jean-Baptiste Lamarck (1744-1829) as being entirely wrong that behavior or life experience could impact inheritance, but it turns out he was only about 99% wrong. Of course, Lamarck didn’t have any correct notion of how that process worked but, then again, Darwin didn’t know about DNA either. The difference is that Darwin knew what he didn’t know, whereas Lamarck filled in the unknown with fantastic theories. Kean describes epigenetics as cell software, with DNA genes acting as hardware.

While the book has good paintings and photos, more scientific illustrations would be helpful for DNA, RNA, proteins, chromosomes and the double helix. For that, I’d advise keeping Wikipedia handy as you read. While Francis Crick and James Watson are mentioned, their work on the double-helix isn’t prominently featured. That’s good in a way because it would be a shame to distill such an interesting story down to better-known figures. Kean’s latest work, The Tale of the Dueling Neurosurgeons (2014), forms a trilogy with Disappearing Spoon and Violinist’s Thumb, but let’s hope he doesn’t stop there.