“Renegade scientists and totalitarian loonies are not the folks most likely to abuse genetic engineering. You and I are—not because we are bad, but because we want to do good.”
Arthur Caplan
In the beginning, so the Bible reports, God gave us the most precious gift of all: free will. Adam and Eve cashed in on that freedom and the rest, as they say, is history.
Nowhere is our storied willfulness more evident than in our relationship with nature, God’s creation. Over the millennia, our choices—our myriad preferences for certain plant and animal traits—have systematically recreated the living world in our own image.
Some call it playing God. Others see it as we humans simply exercising, for better or worse, our God-given free will.
As I’ll explain in this section, both claims are true.
But what’s also true—and is often overlooked in today’s heated debates about genetic engineering—is nature is not static. Natural forces, and we along with them, have been constantly meddling with the original world long before science was ever born.
Long before the theory of evolution, our ancient ancestors could plainly see some plants, animals, and people are hardier than others. They’re better able to survive adversities—harsh winters, famines, droughts, storms, diseases, climate change—and can even turn them into opportunities for advancement.
That, in a nutshell, is Charles Darwin’s concept of natural selection. A concept he spelled out in his famous tome On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, published in 1859.
In the face of an ever-changing environment, Darwin argued, a single trait can “determine which individual shall live and which shall die—which variety or species shall increase in number, and which shall decrease, or finally become extinct.”750
Darwin claimed something else: nature is constantly and randomly introducing new traits we pass on to our offspring. We now know these variations are caused, for example, by glitches in the normal reproduction process and by cosmic rays, toxic chemicals, and other environmental, mutagenic forces constantly dinging our DNA.751
These natural sources of new traits perpetuate a diversity among living organisms. They increase the odds at least some individuals of a species will have the “right stuff” to fend off whatever nature throws at them.
The fabled American Chestnut tree, for instance, once carpeted the eastern United States from Maine to Florida, and from the Piedmont plateau to the Ohio Valley. During the first half of the twentieth century, nearly all the estimated four billion trees on 200 million acres were decimated by a fungus accidently imported from Japan.752
The loss was devastating, because the tree’s unusually hard, rot-resistant wood was widely used to build log cabins, furniture, fence posts, railroad ties, you name it. Also, turkeys, bears, raccoon, deer, and squirrels relished the chestnut tree’s sweet, flavorful nuts—as did we, especially roasted at Christmastime.753
“I think of it as the miracle tree,” says Tom Klak, a professor at the University of New England, in Saco, Maine. He’s one of many people now working hard to reverse the American Chestnut’s tragic fortunes.754
A reversal is possible in part because a few American Chestnut trees chanced to have traits that protected them from the devastating blight. Several years ago one such lucky survivor was spotted from the air, growing in a forest in Lovell, Maine, a tiny town of 1,140 residents.755
In December 2015, Brian Roth, a University of Maine arborist, trudged through the forest on foot and helped confirm the extraordinary find. “We think it’s around one hundred years old,” he says. He and his colleagues also determined that the hearty survivor is 115 feet high, making it the tallest known American Chestnut living in North America.756
By propagating this tree’s blight-resistant traits—along with those of other known survivors—scientists nationwide hope to do the seemingly impossible. “We see real promise of the future to bring the species back,” says Lisa Thompson, president of the American Chestnut Foundation.757
Some people believe natural selection created living organisms from scratch. Others believe God created the major templates of life, the basic species, which the process of natural selection now constantly tweaks.
Either way, surely we can all agree natural selection is an elegant way to maintain the health and wellbeing of living organisms struggling to survive on a ferociously dynamic planet. The alternative—a completely static world, where lifeforms never change—is not realistic, healthy, or at all interesting.
“There is no permanent status quo in nature; all is in the process of adjustment and readjustment,” observed the late Nobel Prize-winning American geneticist Hermann Joseph Muller. “But man . . . has the power to note this changefulness, and, if he will, to turn it to his own advantage.”758 For better and worse, that is precisely what we have done, for as long as our species has existed.
Look around you. Neither natural selection nor God created many of the living organisms we most cherish. We did.
Before we got our hands on them, for instance, “carrots were white and spindly. Wheat was tall and scrawny with little calorific value,” explains James Kennedy, a celebrated science instructor at Australia’s Haileybury Institute. “Apples were tiny and sour with giant pips (like crab-apples today). Strawberries were tiny, bananas had stones in them, and pigs were vicious creatures with tiny backsides that made for a not-so-delicious ham. Cows didn’t produce much milk (just enough for their own calves), and chickens were skinny little creatures that laid eggs weekly rather than daily.”
Left up to natural selection or the Almighty, tomatoes would still be the size of peas, corn would be little more than a grass head, and dogs wouldn’t exist. These organisms—and many, many others—are our creations. The result of thousands of years of artificial selection—of unconscious and deliberate human choices.
Here are some historic examples of how, by trumping natural selection and God, artificial selection systematically produced three of our all-time favorite things.
Tomatoes
In prehistoric times, wild tomatoes—no bigger than shelled peas— grew aplenty in the Andes mountains of Peru, Ecuador, and Bolivia. About two thousand years ago, natives carried the straggly vines northward to Mexico.759 Then, in the sixteenth century, Old World explorers transported them across the Atlantic Ocean to Europe.760
Italians were among the first to develop a taste for the tiny red fruits—along with the French, who called them pommes d’amour, or “love apples.” Early on, the British grew tomato plants only as ornamentals, believing the fruits to be poisonous. After all, they do belong to the nightshade family.761
For two hundred years, those early Europeans artificially selected and promulgated traits of the wild tomato that, among other things, greatly swelled its size. Then, during the eighteenth and nineteenth centuries, when hordes of Europeans migrated to the United States, the new varieties came with them.
We can only imagine how astonished native Americans were when they first laid eyes on the fruit. Their beloved lowly, pea-sized tomato had returned to the New World—one hundred times larger!762
Corn
Nine thousand years ago, southern Mexico’s Balsas River Valley was blanketed by a wild grass called teosinte. According to most scientists and historians, native Americans living there used artificial selection to steadily transform the plentiful grass into maize, AKA corn.763
“The most impressive aspect of the maize story is what it tells us about the capabilities of agriculturalists 9,000 years ago,” remarks Sean Carroll, a biologist at the University of Wisconsin–Madison. “These people were living in small groups and shifting their settlements seasonally. Yet they were able to transform a grass with many inconvenient, unwanted features into a high-yielding, easily harvested food crop.”764
Compared with those of the lowly teosinte, the kernels of today’s corn are (1) one-thousand times larger, (2) three times sweeter, and (3) many times softer. Moreover, corn is now the most prolific grain crop in the world,765 comprising one-fifth of the global human diet.766
“It is grown successfully in every continent but Antarctica,” note Ken Russell and Leah Sandall, agronomists at the University of Nebraska-Lincoln, “from equatorial lowlands to the Matanuska Valley in southern Alaska to Andean highlands that are 12,000 feet above sea level.”767
Dogs
Of all the masterpieces we’ve created with artificial selection, dogs are one of the oldest and most beloved. Paleontological evidence indicates we bred dogs a very long time ago from a single, docile wolf species—the exact one being a matter of lively debate.768
In 2011 an international team of scientists reported discovering the 33,000-year-old “well-preserved remains of a dog-like canid” inside a Southern Siberian cave. After careful analysis, they concluded it is “most similar to fully domesticated dogs from Greenland . . .”769
According to the Fédération Cynologique Internationale (World Canine Organization), there are now more than 340 different breeds of dog.770 That means “Man’s best friend” gets the blue ribbon for the most diversified mammal on the planet.771
Despite Darwin’s historic contribution to biology, he and his generation knew virtually nothing about the actual science of heritable traits, the mechanism that controls the size and shape of, say, a finch’s beak or an elephant’s trunk. In fact, the subject confounded Darwin greatly.
Darwin believed heritable traits behaved like paint. That if a black cat mates with a white cat, their offspring will be various shades of gray, mixtures of white and black. Yet he knew, in fact, such marriages often produce kittens of pure black or pure white.772
The vexing mystery was solved during Darwin’s lifetime by an obscure Austrian Augustinian monk named Gregor Johann Mendel, but Darwin and his contemporaries mostly didn’t notice and didn’t care.773 In fact, in what surely rates as one of the great missed opportunities in the history of science, even Mendel lost interest in the subject and became the abbot of his beloved St. Thomas’s Abbey, in Brno, Czech Republic.774
Father Gregor Mendel’s simple yet powerful experiments with some 10,000 pea plants are now universally recognized as the founding of modern genetics, which is today making headlines with its breathtaking developments in genetic engineering. “Mendel is a giant in the history of genetics,” says David Fankhauser, a biologist at the University of Cincinnati. “I especially admire that he used very simple research techniques that anybody could have duplicated.”775
From 1856 to 1863, Mendel crossbred many different varieties of pea plants: tall with short; smooth-seeded with wrinkle-seeded; yellow pea with green-pea; and so forth. At the end of each growing season, he carefully noted the traits of the various offspring. By some estimates, in eight years he meticulously tabulated the traits of some 40,000 blossoms and 300,000 peas.776
Mendel’s grand conclusion?
Traits do not mix like paint. Rather, they are determined by heritable particles (we now call them genes), each of which comprises a pair of smaller particles (alleles) that come in two strengths: dominant and recessive.777
Human hairlines, for instance, appear to be controlled by a single gene with two well-known alleles. The allele for a widow’s peak (W) is dominant; the allele for a straight hairline (s) is recessive. If a fetus inherits the W from, say, Dad and the s from Mom—thus inheriting the combination Ws—the two alleles will duke it out and the dominant one will win. The child will grow up to have a widow’s peak.778
Altogether, there are four possible combinations of hairline alleles— WW, ss, Ws, sW—three of which are dominated by a W. Over the long haul, therefore, three out of four fetuses will be born to have a widow’s peak. The only times straight hairlines win out are when there is no dominant W in the gene—namely, ss.
This is the simple yet powerful mathematical reasoning Father Gregor Mendel used to compute the exact proportions of different heritable traits. For that reason, today’s biologists call them Mendelian ratios.779
In 1869, just six years after the end of Mendel’s unsung experiments, another obscure researcher—Swiss chemist Friedrich Miescher— discovered a strange, new chemical substance dwelling within the nuclei of human white blood cells. He called it nuclein.
It was a revelation comparable to Christopher Columbus discovering the New World; yet—shades of Mendel—no one paid much attention. During the first decades of the twentieth century, however, a parade of scientists—among them, Phoebus Levene, Oswald Avery, and Erwin Chargaff—picked up the ball and ran with it. They determined the chemical composition of Miescher’s nuclein to be a complex, organic substance called deoxyribonucleic acid (DNA). Moreover, they fingered it as nothing less than the sum and substance of Mendel’s heritable particles—genes, alleles, and all.780
Curious to know more about it, subsequent scientists pounced on DNA with their cameras, like paparazzi chasing after a Hollywood starlet. By the early 1950s, English researchers Rosalind Franklin, Maurice Wilkins, and Raymond Gosling successfully produced some of the most revealing x-ray photos of the elusive celebrity molecule.781
Then on February 28, 1953, came the stunning announcement by American James Watson and Englishman Francis Crick. The molecular biologists successfully puzzled out the structure of DNA and thereby, in Crick’s words, “found the secret of life.”782
DNA, they discovered, is a long, twisting molecule composed of chemical pairs. Picture a long parade of school kids walking two-by-two, each pair holding hands.
Whereas there are two kinds of kids—boy (B) and girl (G)—there are four kinds of basic DNA chemicals: adenine (A), thymine (T), gua-nine (G), and cytosine (C). Moreover, whereas you can pair kids any way you wish—BG, BB, or GG—with DNA, A always pairs with T, and G always pairs with C. So, a stretch of DNA might look something like AT-AT-GC-AT-GC-GC-GC, and so forth.
Armed with that sensational knowledge, molecular biologists were naturally eager to start mapping the DNA molecules of every known plant and animal species. In 1990, when they finally had the right tools for the job, they set about to diagram the most consequential DNA molecule of all: the human genome.
The monumental undertaking—called the Human Genome Project (HGP)—proved every bit as challenging as landing an astronaut on the moon and took thirteen years to complete. But what an historic accomplishment it was, when in April 2003, HGP scientists actually published the human genome’s sequence of roughly 3.2 billion DNA chemical pairs.783
“Without a doubt, this is the most important, most wondrous map ever produced by humankind,” declared President Bill Clinton. “Today, we are learning the language in which God created life. We are gaining ever more awe for the complexity, the beauty, and the wonder of God’s most divine and sacred gift.”784
For thousands of years—ignorant of what controlled heritable traits—we were merely matchmakers, breeding A with B, in hopes of getting C. But with the successful completion of the Human Genome Project, we instantly became genetic engineers, theoretically able to manipulate DNA molecules directly, precisely, and at will. All we lacked were cheap and effective tools for doing it.
That changed several years ago, when genetic engineers from Harvard, MIT, and UC Berkeley co-developed a powerful set of gene-editing tools collectively called CRISPR. It is pronounced CHRIS-per and stands for—are you ready?—Clustered Regularly Interspaced Short Palindromic Repeats.
Got that?
Fortunately, you don’t need to know exactly what it means to understand how CRISPR works, which conceptually is alarmingly simple. Inspired by the extraordinary gene-editing abilities of a typical bacterium’s immune system, of all things, CRISPR works this way:
1. For “eyes,” it uses an organic molecule (ribonucleic acid, or RNA) to find the target gene’s precise location along the long, twisted strand of DNA.
2. For “scissors,” it uses special chemical enzymes (with names such as Cas9 and Cpf1) to snip both ends of the targeted gene.
3. Sensing damage, the wounded DNA molecule sets about to repair itself. At that very moment, CRISPR uses the aforesaid enzyme as “hands” to replace the excised gene with a new, ostensibly improved one.
CRISPR is currently being used to alter the genetic identity of plants, animals, and humans—which, understandably, has many cheerleaders hailing it as one of the greatest inventions of all time. Some of the hypesters are even predicting CRISPR will enable us to at last “cure diseases, curb world hunger, end pesticide use and save endangered species”785—in short, to create Garden of Eden 2.0.
Theoretically, it certainly has the potential to do that. But will it?
Will the creation story currently being written by genetic engineers turn out better than the biblical one? Or will the new storyline merely recapitulate the old one? Or worse.
Read on and judge for yourself.