The Violinist's Thumb: And Other Lost Tales of Love, War, and Genius, as Written by Our Genetic Code (4 page)

Meanwhile other scientists’ doubts about DNA began to
solidify, in their minds, into hard opposition. Most damning, scientists discovered that there was more to chromosomes than phosphate-sugar backbones and A-C-G-T bases. Chromosomes also contained protein nuggets, which seemed more likely candidates to explain chemical heredity. That’s because proteins were composed of twenty different subunits (called amino acids). Each of these subunits could serve as one “letter” for writing chemical instructions, and there seemed to be enough variety among these letters to explain the dazzling diversity of life itself. The A, C, G, and T of DNA seemed dull and simplistic in comparison, a four-letter pidgin alphabet with limited expressive power. As a result, most scientists decided that DNA stored phosphorus for cells, nothing more.

Sadly, even Miescher came to doubt that DNA contained enough alphabetical variety. He too began tinkering with protein inheritance, and developed a theory where proteins encoded information by sticking out molecular arms and branches at different angles—a kind of chemical semaphore. It still wasn’t clear how sperm passed this information to eggs, though, and Miescher’s confusion deepened. He turned back to DNA late in life and argued that it might assist with heredity still. But progress proved slow, partly because he had to spend more and more time in tuberculosis sanitariums in the Alps. Before he got to the bottom of anything, he contracted pneumonia in 1895, and succumbed soon after.

Later work continued to undermine Miescher by reinforcing the belief that even if chromosomes control inheritance, the proteins in chromosomes, not the DNA, contained the actual information. After Miescher’s death, his uncle, a fellow scientist, gathered Miescher’s correspondence and papers into a “collected works,” like some belle-lettrist. The uncle prefaced the book by claiming that “Miescher and his work will not diminish; on the contrary, it will grow and his discoveries and thoughts will be
seeds for a fruitful future.” Kind words, but it must have seemed a fond hope: Miescher’s obituaries barely mentioned his work on nuclein; and DNA, like Miescher himself, seemed decidedly minor.

At least Miescher died known, where he was known, for science. Gregor Mendel made a name for himself during his lifetime only through scandal.

By his own admission, Mendel became an Augustinian friar not because of any pious impulse but because his order would pay his bills, including college tuition. The son of peasants, Mendel had been able to afford his elementary school only because his uncle had founded it; he attended high school only after his sister sacrificed part of her dowry. But with the church footing the bill, Mendel attended the University of Vienna and studied science, learning experimental design from Christian Doppler himself, of the eponymous effect. (Though only after Doppler rejected Mendel’s initial application, perhaps because of Mendel’s habit of having nervous breakdowns during tests.)

The abbot at St. Thomas, Mendel’s monastery, encouraged Mendel’s interest in science and statistics, partly for mercenary reasons: the abbot thought scientific farming could produce better sheep, fruit trees, and grapevines and help the monastery crawl out of debt. But Mendel had time to explore other interests, too, and over the years he charted sunspots, tracked tornadoes, kept an apiary buzzing with bees (although one strain he bred was so nasty-tempered and vindictive it had to be destroyed), and cofounded the Austrian Meteorological Society.

In the early 1860s, just before Miescher moved from medical school into research, Mendel began some deceptively simple experiments on pea plants in the St. Thomas nursery. Beyond enjoying their taste and wanting a ready supply, he chose peas
because they simplified experiments. Neither bees nor wind could pollinate his pea blossoms, so he could control which plants mated with which. He appreciated the binary, either/or nature of pea plants, too: plants had tall or short stalks, green or yellow pods, wrinkled or smooth peas, nothing in between. In fact, Mendel’s first important conclusion from his work was that some binary traits “dominated” others. For example, crossing purebred green-pead plants with purebred yellow-pead plants produced only yellow-pead offspring: yellow dominated. Importantly, however, the green trait hadn’t disappeared. When Mendel mated those second-generation yellow-pead plants with each other, a few furtive green peas popped up—one latent, “recessive” green for every three dominant yellows.
The 3:1 ratio
^*
held for other traits, too.

Equally important, Mendel concluded that having one dominant or recessive trait didn’t affect whether another, separate trait was dominant or recessive—each trait was independent. For example, even though tall dominated short, a recessive-short plant could still have dominant-yellow peas. Or a tall plant could have recessive-green peas. In fact, every one of the seven traits he studied—like smooth peas (dominant) versus wrinkled peas (recessive), or purple blossoms (dominant) versus white blossoms (recessive)—was inherited independently of the other traits.

This focus on separate, independent traits allowed Mendel to succeed where other heredity-minded horticulturists had failed. Had Mendel tried to describe, all at once, the overall resemblance of a plant to its parents, he would have had too many traits to consider. The plants would have seemed a confusing collage of Mom and Dad. (Charles Darwin, who also grew
and experimented with pea plants, failed to understand their heredity partly for this reason.) But by narrowing his scope to one trait at a time, Mendel could see that each trait must be controlled by a separate factor. Mendel never used the word, but he identified the discrete, inheritable factors we call genes today. Mendel’s peas were the Newton’s apple of biology.

Beyond his qualitative discoveries, Mendel put genetics on solid quantitative footing. He adored the statistical manipulations of meteorology, the translating of daily barometer and thermometer readings into aggregate climate data. He approached breeding the same way, abstracting from individual plants into general laws of inheritance. In fact, rumors have persisted for almost a century now that Mendel got carried away here, letting his love of perfect data tempt him into fraud.

If you flip a dime a thousand times, you’ll get approximately five hundred FDRs and five hundred torches; but you’re unlikely to get exactly five hundred of either, because each flip is independent and random. Similarly, because of random deviations, experimental data always stray a tad higher or lower than theory predicts. Mendel should therefore have gotten only approximately a 3:1 ratio of tall to short plants (or whatever other trait he measured). Mendel, however, claimed some almost platonically perfect 3:1s among his thousands of pea plants, a claim that has raised suspicions among modern geneticists. One latter-day fact checker calculated the odds at less than one in ten thousand that Mendel—otherwise a pedant for numerical accuracy in ledgers and meteorological experiments—came by his results honestly. Many historians have defended Mendel over the years or argued that he manipulated his data only unconsciously, since standards for recording data differed back then. (One sympathizer even invented, based on no evidence, an overzealous gardening assistant who knew what numbers Mendel wanted and furtively discarded plants to please his master.) Mendel’s original
lab notes were burned after his death, so we can’t check if he cooked the books. Honestly, though, if Mendel did cheat, it’s almost more remarkable: it means he intuited the correct answer—the golden 3:1 ratio of genetics—before having any real proof. The purportedly fraudulent data may simply have been the monk’s way of tidying up the vagaries of real-world experiments, to make his data more convincing, so that others could see what he somehow knew by revelation.

Regardless, no one in Mendel’s lifetime suspected he’d pulled a fast one—partly because no one was paying attention. He read a paper on pea heredity at a conference in 1865, and as one historian noted, “his audience dealt with him in the way that all audiences do when presented with more mathematics than they have a taste for: there was no discussion, and no questions were asked.” He almost shouldn’t have bothered, but Mendel published his results in 1866. Again, silence.

Mendel kept working for a few years, but his chance to burnish his scientific reputation largely evaporated in 1868, when his monastery elected him abbot. Never having governed anything before, Mendel had a lot to learn, and the day-to-day headaches of running St. Thomas cut into his free time for horticulture. Moreover, the perks of being in charge, like rich foods and cigars (Mendel smoked up to twenty cigars per day and grew so stout that his resting pulse sometimes topped 120), slowed him down, limiting his enjoyment of the gardens and greenhouses. One later visitor did remember Abbot Mendel taking him on a stroll through the gardens and pointing out with delight the blossoms and ripe pears; but at the first mention of his own experiments in the garden, Mendel changed the subject, almost embarrassed. (Asked how he managed to grow nothing but tall pea plants, Mendel demurred: “It is just a little trick, but there is a long story connected with it, which would take too long to tell.”)

Mendel’s scientific career also atrophied because he wasted
an increasing number of hours squabbling about political issues, especially separation of church and state. (Although it’s not obvious from his scientific work, Mendel could be fiery—a contrast to the chill of Miescher.) Almost alone among his fellow Catholic abbots, Mendel supported liberal politics, but the liberals ruling Austria in 1874 double-crossed him and revoked the tax-exempt status of monasteries. The government demanded seventy-three hundred gulden per year from St. Thomas in payment, 10 percent of the monastery’s assessed value, and although Mendel, outraged and betrayed, paid some of the sum, he refused to pony up the rest. In response, the government seized property from St. Thomas’s farms. It even dispatched a sheriff to seize assets from inside St. Thomas itself. Mendel met his adversary in full clerical habit outside the front gate, where he stared him down and dared him to extract the key from his pocket. The sheriff left empty-handed.

Overall, though, Mendel made little headway getting the new law repealed. He even turned into something of a crank, demanding interest for lost income and writing long letters to legislators on arcane points of ecclesiastical taxation. One lawyer sighed that Mendel was “full of suspicion, [seeing] himself surrounded by nothing but enemies, traitors, and intriguers.” The “Mendel affair” did make the erstwhile scientist famous, or notorious, in Vienna. It also convinced his successor at St. Thomas that Mendel’s papers should be burned when he died, to end the dispute and save face for the monastery. The notes describing the pea experiments would become collateral casualties.

Mendel died in 1884, not long after the church-state imbroglio; his nurse found him stiff and upright on his sofa, his heart and kidneys having failed. We know this because Mendel feared being buried alive and had demanded a precautionary autopsy. But in one sense, Mendel’s fretting over a premature burial proved prophetic. Just eleven scientists cited his now-classic
paper on inheritance in the thirty-five years after his death. And those that did (mostly agricultural scientists) saw his experiments as mildly interesting lessons for breeding peas, not universal statements on heredity. Scientists had indeed buried Mendel’s theories too soon.

But all the while, biologists were discovering things about cells that, if they’d only known, supported Mendel’s ideas. Most important, they found distinct ratios of traits among offspring, and determined that chromosomes passed hereditary information around in discrete chunks, like the discrete traits Mendel identified. So when three biologists hunting through footnotes around 1900 all came across the pea paper independently and realized how closely it mirrored their own work, they grew determined to resurrect the monk.

Mendel allegedly once vowed to a colleague, “My time will come,” and boy, did it. After 1900 “Mendelism” expanded so quickly, with so much ideological fervor pumping it up, that it began to rival Charles Darwin’s natural selection as the preeminent theory in biology. Many geneticists in fact saw Darwinism and Mendelism as flatly incompatible—and a few even relished the prospect of banishing Darwin to the same historical obscurity that Friedrich Miescher knew so well.

T
his was not how a Nobel laureate should have to spend his time. In late 1933, shortly after winning science’s highest honor, Thomas Hunt Morgan got a message from his longtime assistant Calvin Bridges, whose libido had landed him in hot water. Again.

A “confidence woman” from Harlem had met Bridges on a cross-country train a few weeks before. She quickly convinced him not only that she was a regal princess from India, but that her fabulously wealthy maharaja of a father just happened to have opened—coincidence of all coincidences—a science institute on the subcontinent in the very field that Bridges (and Morgan) worked in, fruit fly genetics. Since her father needed a man to head the institute, she offered Bridges the job. Bridges, a real Casanova, would likely have shacked up with the woman anyway, and the job prospect made her irresistible. He was so smitten he began offering his colleagues jobs in India and didn’t seem to notice Her Highness’s habit of running up extraordinary bills whenever they went carousing. In fact, when out of
earshot, the supposed princess claimed to be Mrs. Bridges and charged everything she could to him. When the truth emerged, she tried to extort more cash by threatening to sue him “for transporting her across state lines for immoral purposes.” Panicked and distraught—despite his adult activities, Bridges was quite childlike—he turned to Morgan.