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

Fruit fly scientists, God bless ‘em, are the big exceptions. Morgan’s team always picked sensibly descriptive names for mutant genes, like ‘speck,’ ‘beaded,’ ‘rudimentary,’ ‘white,’ and ‘abnormal.’ And this tradition continues today, as the names of most fruit fly genes eschew jargon and even shade whimsical… The ‘turnip’ gene makes flies stupid. ‘Tudor’ leaves males (as with Henry VIII) childless. ‘Cleopatra’ can kill flies when it interacts with another gene, ‘asp.’ ‘Cheap date’ leaves flies exceptionally tipsy after a sip of alcohol… And thankfully, this whimsy with names has inspired the occasional zinger in other areas of genetics… The backronym for the “POK erythroid myeloid ontogenic” gene in mice—‘pokemon’—nearly provoked a lawsuit, since the ‘pokemon’ gene (now known, sigh, as ‘zbtb7’) contributes to the spread of cancer, and the lawyers for the Pokemon media empire didn’t want their cute little pocket monsters confused with tumors.

The irony is too rich not to point out. When arranging the different human races in tiers, from just below the angels to just above the brutes, smug racialist scientists of the 1800s always equated black skin with ‘subhuman’ beasts like Neanderthals. But facts is facts: pure Nordic Europeans carry far more Neanderthal DNA than any modern African.

The emerging and vital truth isn’t who is more Neanderthal than whom. It’s that all peoples, everywhere, enjoyed archaic human lovers whenever they could. These DNA memories are buried deeper inside us than even our ids, and they remind us that the grand saga of how humans spread across the globe will need some personal, private, all-too-human amendments and annotations—rendezvous here, elopements there, and the commingling of genes most everywhere.

For ages anthropologists lumped all African peoples into one ‘race,’ but the genetic truth is that the larger world’s diversity is more or less a subset of African diversity.

You're not supposed to interject feelings into science, but part of the reason it's so fascinating that we're 8 percent (or more) fossilized virus is that it's so creepy that we're 8 percent (or more) fossilized virus.

S-A-T-O-RA-R-E-P-O T-E-N-E-T O-P-E-R-A R-O-T-A-SThe palindrome means something like “The farmer Arepo works with his plow,” with rotas, literally “wheels,” referring to the back-and-forth motion that plows make as they till. This “magic square” has delighted enigmatologists for centuries ... The magic square also reportedly kept away the devil, who traditionally (so said the church) got confused when he read palindromes.

In a touch Buckland would have appreciated, this multipronged dispersal from Africa is sometimes called the Weak Garden of Eden theory. But this tale is actually better than the biblical version; we didn’t lose Eden but learned to make other Edens across the world.

But for years questions persisted about whether most cannibalism was religiously motivated and selective or culinary and routine. DNA suggests routine. Every known ethnic group worldwide has one of two genetic signatures that help our bodies fight off certain diseases that cannibals catch, especially mad-cow-like diseases that come from eating each other’s brains. This defensive DNA almost certainly wouldn’t have become fixed worldwide if it hadn’t once been all too necessary.

Great literature remains great when it says new things to new generations, and the loops of a knot quite nicely parallel the contours and convolutions of Carroll’s plot anyway.What’s more, he probably would have been delighted at how this whimsical branch of math invaded the real world and became crucial to understanding our biology.

ancestor. In fact, this clock tells us that all seven billion people alive today can trace their maternal lineage to one woman who lived in Africa 170,000 years ago, dubbed “Mitochondrial Eve.

Art, in other words, betrays a sexy mental fitness.

But to understand what DNA and genes really are, we have to decouple the two words. They’re not identical and never have been. DNA is a thing—a chemical that sticks to your fingers. Genes have a physical nature, too; in fact, they’re made of long stretches of DNA. But in some ways genes are better viewed as conceptual, not material. A gene is really information—more like a story, with DNA as the language the story is written in. DNA and genes combine to form larger structures called chromosomes, DNA-rich volumes that house most of the genes in living things. Chromosomes in turn reside in the cell nucleus, a library with instructions that run our entire bodies.

The key point is that these patterns, while mostly stable, are not permanent: certain environmental experiences can add or subtract methyls and acetyls, changing those patterns. In effect this etches a memory of what the organism was doing or experiencing into its cells—a crucial first step for any Lamarck-like inheritance. Unfortunately, bad experiences can be etched into cells as easily as good experiences. Intense emotional pain can sometimes flood the mammal brain with neurochemicals that tack methyl groups where they shouldn’t be. Mice that are (however contradictory this sounds) bullied by other mice when they’re pups often have these funny methyl patterns in their brains. As do baby mice (both foster and biological) raised by neglectful mothers, mothers who refuse to lick and cuddle and nurse. These neglected mice fall apart in stressful situations as adults, and their meltdowns can’t be the result of poor genes, since biological and foster children end up equally histrionic. Instead the aberrant methyl patterns were imprinted early on, and as neurons kept dividing and the brain kept growing, these patterns perpetuated themselves. The events of September 11, 2001, might have scarred the brains of unborn humans in similar ways. Some pregnant women in Manhattan developed post-traumatic stress disorder, which can epigenetically activate and deactivate at least a dozen genes, including brain genes. These women, especially the ones affected during the third trimester, ended up having children who felt more anxiety and acute distress than other children when confronted with strange stimuli. Notice that these DNA changes aren’t genetic, because the A-C-G-T string remains the same throughout. But epigenetic changes are de facto mutations; genes might as well not function. And just like mutations, epigenetic changes live on in cells and their descendants. Indeed, each of us accumulates more and more unique epigenetic changes as we age. This explains why the personalities and even physiognomies of identical twins, despite identical DNA, grow more distinct each year. It also means that that detective-story trope of one twin committing a murder and both getting away with it—because DNA tests can’t tell them apart—might not hold up forever. Their epigenomes could condemn them. Of course, all this evidence proves only that body cells can record environmental cues and pass them on to other body cells, a limited form of inheritance. Normally when sperm and egg unite, embryos erase this epigenetic information—allowing you to become you, unencumbered by what your parents did. But other evidence suggests that some epigenetic changes, through mistakes or subterfuge, sometimes get smuggled along to new generations of pups, cubs, chicks, or children—close enough to bona fide Lamarckism to make Cuvier and Darwin grind their molars.

Any flesh or fluid from any beast was eligible for ingestion, be it blood, skin, gristle, or worse. While touring a church once, Buckland startled a local vicar—who was showing off the miraculous “martyr’s blood” that dripped from the rafters every night—by dropping to the stone floor and dabbing the stain with his tongue. Between laps Buckland announced, “It’s bat urine.” Overall Buckland found few animals he couldn’t stomach: “The taste of mole was the most repulsive I knew,” he once mused. “Until I tasted a bluebottle [fly].”*

Polar bears began evolving their impressive vitamin A–fighting capabilities around 150,000 years ago, when small groups of Alaskan brown bears split off and migrated north to the ice caps.