Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100 (26 page)

In addition, the “mighty mouse gene” has been isolated, which increases the muscle mass so that the mouse appears to be musclebound. It was first found in mice with unusually large muscles. Scientists now realize that the key lies in the myostatin gene, which helps to keep muscle growth in check. But in 1997, scientists found that when the myostatin gene is silenced in mice, muscle growth expands enormously.

Another breakthrough was made soon afterward in Germany, when scientists examined a newborn boy who had unusual muscles in his upper legs and arms. Ultrasound analysis showed that this boy’s muscles were twice as large as normal. By sequencing the genes of this baby and of his mother (who was a professional sprinter), they found a similar genetic pattern. In fact, an analysis of the boy’s blood showed no myostatin whatsoever.

Scientists at the Johns Hopkins Medical School were at first eager to make contact with patients suffering from degenerative muscle disorders who might benefit from this result, but they were disappointed to find that half the telephone calls to their office came from bodybuilders who wanted the gene to bulk themselves up, regardless of the consequences. Perhaps these bodybuilders were recalling the phenomenal success of Arnold Schwarzenegger, who has admitted to using steroids to jump-start his meteoric career. Because of the intense interest in the myostatin gene and ways to suppress it, even the Olympic Committee was forced to set up a special commission to look into it. Unlike steroids, which are relatively easy to detect via chemical tests, this new method, because it involves genes and the proteins they create, is much more difficult to detect.

Studies done on identical twins who have been separated at birth show that there is a wide variety of behavioral traits influenced by genetics. In fact, these studies show that roughly 50 percent of a twin’s behavior is influenced by genes, the other 50 percent by environment. These traits include memory, verbal reasoning, spatial reasoning, processing speed, extroversion, and thrill seeking.

Even behaviors once thought to be complex are now revealing their genetic roots. For example, prairie voles are monogamous. Laboratory mice are promiscuous. Larry Young at Emory University shocked the world of biotechnology by showing that the transfer of one gene from prairie voles could create mice that exhibited monogamous characteristics. Each animal has a different version of a certain receptor for a brain peptide associated with social behavior and mating. Young inserted the vole gene for this receptor into the mice and found that the mice then exhibited behaviors more like the monogamous voles.

Young said, “Although many genes are likely to be involved in the evolution of complex social behaviors such as monogamy … changes in the expression of a single gene can have an impact on the expression of components of these behaviors, such as affiliation.”

Depression and happiness may also have genetic roots. It has long been known that there are people who are happy even though they may have suffered tragic accidents. They always see the brighter side of things, even in the face of setbacks that may devastate another individual. These people also tend to be healthier than normal. Harvard psychologist Daniel Gilbert told me that there is a theory that might explain this. Perhaps we are born with a “happiness set point.” Day by day we may oscillate around this set point, but its level is fixed at birth. In the future, via drugs or gene therapy, one may be able to shift this set point, especially for those who are chronically depressed.

SIDE EFFECTS OF THE BIOTECH REVOLUTION

By midcentury, scientists will be able to isolate and alter many of the single genes that control a variety of human characteristics. But this does not mean humanity will immediately benefit from them. There is also the long, hard work of ironing out side effects and unwanted consequences, which will take decades.

For example, Achilles was invincible in combat, leading the victorious Greeks in their epic battle with the Trojans. However, his power had a fatal flaw. When he was a baby, his mother dipped him into the magic river Styx in order to make him invincible. Unfortunately, she had to hold him by the heel when she placed him into the river, leaving that one crucial point of vulnerability. Later, he would die during the Trojan War after being hit in the heel by an arrow.

Today, scientists are wondering if the new strains of creatures emerging from their laboratories also have a hidden Achilles’ heel. For example, today there are about thirty-three different “smart mouse” strains that have enhanced memory and performance. However, there is an unexpected side effect of having enhanced memory; smart mice are sometimes paralyzed by fear. If they are exposed to an extremely mild electric shock, for example, they will shiver in terror. “It’s as if they remember too much,” says Alcino Silva of UCLA, who developed his own strain of smart mice. Scientists now realize that forgetting may be as important as remembering in making sense of this world and organizing our knowledge. Perhaps we have to throw out a lot of files in order to organize our knowledge.

This is reminiscent of a case from the 1920s, documented by Russian neurologist A. R. Luria, of a man who had a photographic memory. After just a single reading of Dante’s
Divine Comedy,
he had memorized every word. This was helpful in his work as a newspaper reporter, but he was incapable of understanding figures of speech. Luria observed, “The obstacles to his understanding were overwhelming: each expression gave rise to an image; this, in turn, would conflict with another image that had been evoked.”

In fact, scientists believe that there has to be a balance between forgetting and remembering. If you forget too much, you may be able to forget the pain of previous mistakes, but you also forget key facts and skills. If you remember too much, you may be able to remember important details, but you might be paralyzed by the memory of every hurt and setback. Only a trade-off between these two may yield optimal understanding.

Bodybuilders are already flocking to different drugs and therapies that promise them fame and glory. The hormone erythropoietin (EPO) works by making more oxygen-containing red blood cells, which means increased endurance. Because EPO thickens the blood, it also has been linked to strokes and heart attacks. Insulin-like growth factors (IGF) are useful because they help proteins to bulk up muscles, but they have been linked to tumor growth.

Even if laws are passed banning genetic enhancements, they will be difficult to stop. For example, parents are genetically hardwired by evolution to want to give every advantage to their children. On the one hand, this might mean giving them violin, ballet, and sports lessons. But on the other hand, this might mean giving them genetic enhancements to improve their memory, attention span, athletic ability, and perhaps even their looks. If parents find out that their child is competing with a neighbor’s child who is rumored to have been genetically enhanced, there will be enormous pressure to give the same benefit to their child.

As Gregory Benford has said, “We all know that good-looking people do well. What parents could resist the argument that they were giving the child a powerful leg up (maybe literally) in a brave new competitive world?”

By midcentury, genetic enhancements may become commonplace. In fact, genetic enhancements may even be indispensable if we are to explore the solar system and live on inhospitable planets.

Some say that we should use designer genes to make us healthier and happier. Others say that we should allow for cosmetic enhancements. The big question will be how far this will go. In any event, it may become increasingly difficult to control the spread of “designer genes” that enhance looks and performance. We don’t want the human race to split into different genetic factions, the enhanced and the unenhanced, but society will have to democratically decide how far to push this technology.

Personally, I believe that laws will be passed to regulate this powerful technology, possibly to allow gene therapy when it cures disease and allows us to lead productive lives, but to restrict gene therapy for purely cosmetic reasons. This means that a black market might eventually develop to skirt these laws, so we might have to adjust to a society in which a small fraction of the population is genetically enhanced.

For the most part, this might not be a disaster. Already, one can use plastic surgery to improve appearance, so using genetic engineering to do this may be unnecessary. But the danger may arise when one tries to genetically change one’s personality. There are probably many genes that influence behavior, and they interact in complex ways, so tampering with behavioral genes may create unintended side effects. It may take decades to sort through all these side effects.

But what about the greatest gene enhancement of all, extending the human life span?

Throughout history, kings and warlords had the power to command entire empires, but there was one thing that was forever beyond their control: aging. Hence, the search for immortality has been one of the oldest quests in human history.

In the Bible, God banishes Adam and Even from the Garden of Eden for disobeying his orders concerning the apple of knowledge. God’s fear was that Adam and Eve might use this knowledge to unlock the secret of immortality and become gods themselves. In Genesis 3:22, the Bible reads, “Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever.”

Besides the Bible, one of the oldest and greatest tales in human civilization, dating back to the twenty-seventh century BC, is
The Epic of Gilgamesh,
about the great warrior of Mesopotamia. When his lifelong, loyal companion suddenly died, Gilgamesh decided to embark upon a journey to find the secret of immortality. He heard rumors that a wise man and his wife had been granted the gift of immortality by the gods, and were, in fact, the only ones in their land to have survived the Great Flood. After an epic quest, Gilgamesh finally found the secret of immortality, only to see a serpent snatch it away at the last minute.

Because
The Epic of Gilgamesh
is one of the oldest pieces of literature, historians believe that this search for immortality was the inspiration for the Greek writer Homer to write the
Odyssey,
and also for Noah’s flood mentioned in the Bible.

Many early kings—like Emperor Qin, who unified China around 200 BC—sent huge fleets of ships to find the Fountain of Youth, but all failed. (According to mythology, Emperor Qin gave instructions to his fleet not to come back if they failed to find the Fountain of Youth. Unable to find the fountain, but too afraid to return, they founded Japan instead.)

For decades, most scientists believed that life span was fixed and immutable, beyond the reach of science. Within the last few years, this view has crumbled under the onslaught of a stunning series of experimental results that have revolutionized the field. Gerontology, once a sleepy, backwater area of science, has now become one of the hottest fields, attracting hundreds of millions of dollars in research funds and even raising the possibility of commercial development.

The secrets of the aging process are now being unraveled, and genetics will play a vital role in this process. Looking at the animal kingdom, we see a vast variety of life spans. For example, our DNA differs from that of our nearest genetic relative, the chimpanzee, by only 1.5 percent, yet we live 50 percent longer. By analyzing the handful of genes separating us from the chimpanzees, we may be able to determine why we live so much longer than our genetic relative.

This, in turn, has given us a “unified theory of aging” that brings the various strands of research into a single, coherent tapestry. Scientists now know what aging is. It is the accumulation of errors at the genetic and cellular level. These errors can build up in various ways. For example, metabolism creates free radicals and oxidation, which damage the delicate molecular machinery of our cells, causing them to age; errors can build up in the form of “junk” molecular debris accumulating inside and outside the cells.

The buildup of these genetic errors is a by-product of the second law of thermodynamics: total entropy (that is, chaos) always increases. This is why rusting, rotting, decaying, etc., are universal features of life. The second law is inescapable. Everything, from the flowers in the field to our bodies and even the universe itself, is doomed to wither and die.

But there is a small but important loophole in the second law that states
total
entropy always increases. This means that you can actually reduce entropy in one place and reverse aging, as long as you increase entropy somewhere else. So it’s possible to get younger, at the expense of wreaking havoc elsewhere. (This was alluded to in Oscar Wilde’s famous novel
The Picture of Dorian Gray.
Mr. Gray was mysteriously eternally young. But his secret was the painting of himself that aged horribly. So the total amount of aging still increased.) The principle of entropy can also be seen by looking behind a refrigerator. Inside the refrigerator, entropy decreases as the temperature drops. But to lower the entropy, you have to have a motor, which increases the heat generated behind the refrigerator, increasing the entropy outside the machine. That is why refrigerators are always hot in the back.