TED日本語 - ハーヴィ・ファインバーグ: 新進化の準備はできていますか

How would you like to be better than you are? Suppose I said that, with just a few changes in your genes, you could get a better memory -- more precise, more accurate and quicker. Or maybe you'd like to be more fit, stronger, with more stamina. Would you like to be more attractive and self-confident? How about living longer with good health? Or perhaps you're one of those who's always yearned for more creativity. Which one would you like the most? Which would you like, if you could have just one? (Audience Member: Creativity.) Creativity. How many people would choose creativity? Raise your hands. Let me see. A few. Probably about as many as there are creative people here. (Laughter) That's very good. How many would opt for memory? Quite a few more. How about fitness? A few less. What about longevity? Ah, the majority. That makes me feel very good as a doctor. If you could have any one of these, it would be a very different world. Is it just imaginary? Or, is it, perhaps, possible?

Evolution has been a perennial topic here at the TED Conference, but I want to give you today one doctor's take on the subject. The great 20th-century geneticist, T.G. Dobzhansky, who was also a communicant in the Russian Orthodox Church, once wrote an essay that he titled "Nothing in Biology Makes Sense Except in the Light of Evolution." Now if you are one of those who does not accept the evidence for biological evolution, this would be a very good time to turn off your hearing aid, take out your personal communications device -- I give you permission -- and perhaps take another look at Kathryn Schultz's book on being wrong, because nothing in the rest of this talk is going to make any sense whatsoever to you. (Laughter) But if you do accept biological evolution, consider this: is it just about the past, or is it about the future? Does it apply to others, or does it apply to us?

This is another look at the tree of life. In this picture, I've put a bush with a center branching out in all directions, because if you look at the edges of the tree of life, every existing species at the tips of those branches has succeeded in evolutionary terms: it has survived; it has demonstrated a fitness to its environment. The human part of this branch, way out on one end, is, of course, the one that we are most interested in. We branch off of a common ancestor to modern chimpanzees about six or eight million years ago. In the interval, there have been perhaps 20 or 25 different species of hominids. Some have come and gone. We have been here for about 130,000 years. It may seem like we're quite remote from other parts of this tree of life, but actually, for the most part, the basic machinery of our cells is pretty much the same.

Do you realize that we can take advantage and commandeer the machinery of a common bacterium to produce the protein of human insulin used to treat diabetics? This is not like human insulin; this is the same protein that is chemically indistinguishable from what comes out of your pancreas. And speaking of bacteria, do you realize that each of us carries in our gut more bacteria than there are cells in the rest of our body? Maybe 10 times more. I mean think of it, when Antonio Damasio asks about your self-image, do you think about the bacteria? Our gut is a wonderfully hospitable environment for those bacteria. It's warm, it's dark, it's moist, it's very cozy. And you're going to provide all the nutrition that they could possibly want with no effort on their part. It's really like an Easy Street for bacteria, with the occasional interruption of the unintended forced rush to the exit. But otherwise, you are a wonderful environment for those bacteria, just as they are essential to your life. They help in the digestion of essential nutrients, and they protect you against certain diseases.

But what will come in the future? Are we at some kind of evolutionary equipoise as a species? Or, are we destined to become something different -- something, perhaps, even better adapted to the environment? Now let's take a step back in time to the Big Bang,14 billion years ago -- the Earth, the solar system, about four and a half billion years -- the first signs of proto-life, maybe three to four billion years ago on Earth -- the first multi-celled organisms, perhaps as much as 800 or a billion years ago -- and then the human species, finally emerging in the last 130,000 years. In this vast unfinished symphony of the universe, life on Earth is like a brief measure; the animal kingdom, like a single measure; and human life, a small grace note. That was us. That also constitutes the entertainment portion of this talk, so I hope you enjoyed it.

(Laughter)

Now when I was a freshman in college, I took my first biology class. I was fascinated by the elegance and beauty of biology. I became enamored of the power of evolution, and I realized something very fundamental: in most of the existence of life in single-celled organisms, each cell simply divides, and all of the genetic energy of that cell is carried on in both daughter cells. But at the time multi-celled organisms come online, things start to change. Sexual reproduction enters the picture. And very importantly, with the introduction of sexual reproduction that passes on the genome, the rest of the body becomes expendable. In fact, you could say that the inevitability of the death of our bodies enters in evolutionary time at the same moment as sexual reproduction.

Now I have to confess, when I was a college undergraduate, I thought, okay, sex/death, sex/death, death for sex -- it seemed pretty reasonable at the time, but with each passing year, I've come to have increasing doubts. I've come to understand the sentiments of George Burns, who was performing still in Las Vegas well into his 90s. And one night, there's a knock at his hotel room door. He answers the door. Standing before him is a gorgeous, scantily clad showgirl. She looks at him and says, "I'm here for super sex." "That's fine," says George, "I'll take the soup."

(Laughter)

I came to realize, as a physician, that I was working toward a goal which was different from the goal of evolution -- not necessarily contradictory, just different. I was trying to preserve the body. I wanted to keep us healthy. I wanted to restore health from disease. I wanted us to live long and healthy lives. Evolution is all about passing on the genome to the next generation, adapting and surviving through generation after generation. From an evolutionary point of view, you and I are like the booster rockets designed to send the genetic payload into the next level of orbit and then drop off into the sea. I think we would all understand the sentiment that Woody Allen expressed when he said, "I don't want to achieve immortality through my work. I want to achieve it through not dying."

(Laughter)

Evolution does not necessarily favor the longest-lived. It doesn't necessarily favor the biggest or the strongest or the fastest, and not even the smartest. Evolution favors those creatures best adapted to their environment. That is the sole test of survival and success. At the bottom of the ocean, bacteria that are thermophilic and can survive at the steam vent heat that would otherwise produce, if fish were there, sous-vide cooked fish, nevertheless, have managed to make that a hospitable environment for them.

So what does this mean, as we look back at what has happened in evolution, and as we think about the place again of humans in evolution, and particularly as we look ahead to the next phase, I would say that there are a number of possibilities. The first is that we will not evolve. We have reached a kind of equipoise. And the reasoning behind that would be, first, we have, through medicine, managed to preserve a lot of genes that would otherwise be selected out and be removed from the population. And secondly, we as a species have so configured our environment that we have managed to make it adapt to us as well as we adapt to it. And by the way, we immigrate and circulate and intermix so much that you can't any longer have the isolation that is necessary for evolution to take place.

A second possibility is that there will be evolution of the traditional kind, natural, imposed by the forces of nature. And the argument here would be that the wheels of evolution grind slowly, but they are inexorable. And as far as isolation goes, when we as a species do colonize distant planets, there will be the isolation and the environmental changes that could produce evolution in the natural way.

But there's a third possibility, an enticing, intriguing and frightening possibility. I call it neo-evolution -- the new evolution that is not simply natural, but guided and chosen by us as individuals in the choices that we will make. Now how could this come about? How could it be possible that we would do this? Consider, first, the reality that people today, in some cultures, are making choices about their offspring. They're, in some cultures, choosing to have more males than females. It's not necessarily good for the society, but it's what the individual and the family are choosing.

Think also, if it were possible ever for you to choose, not simply to choose the sex of your child, but for you in your body to make the genetic adjustments that would cure or prevent diseases. What if you could make the genetic changes to eliminate diabetes or Alzheimer's or reduce the risk of cancer or eliminate stroke? Wouldn't you want to make those changes in your genes? If we look ahead, these kind of changes are going to be increasingly possible.

The Human Genome Project started in 1990, and it took 13 years. It cost 2.7 billion dollars. The year after it was finished in 2004, you could do the same job for 20 million dollars in three to four months. Today, you can have a complete sequence of the three billion base pairs in the human genome at a cost of about 20,000 dollars and in the space of about a week. It won't be very long before the reality will be the 1, 000-dollar human genome, and it will be increasingly available for everyone. Just a week ago, the National Academy of Engineering awarded its Draper Prize to Francis Arnold and Willem Stemmer,two scientists who independently developed techniques to encourage the natural process of evolution to work faster and to lead to desirable proteins in a more efficient way -- what Frances Arnold calls "directed evolution." A couple of years ago, the Lasker Prize was awarded to the scientist Shinya Yamanaka for his research in which he took an adult skin cell, a fibroblast, and by manipulating just four genes, he induced that cell to revert to a pluripotential stem cell -- a cell potentially capable of becoming any cell in your body.

These changes are coming. The same technology that has produced the human insulin in bacteria can make viruses that will not only protect you against themselves, but induce immunity against other viruses. Believe it or not, there's an experimental trial going on with vaccine against influenza that has been grown in the cells of a tobacco plant. Can you imagine something good coming out of tobacco?

These are all reality today, and [ in ] the future, will be evermore possible. Imagine then just two other little changes. You can change the cells in your body, but what if you could change the cells in your offspring? What if you could change the sperm and the ova, or change the newly fertilized egg, and give your offspring a better chance at a healthier life -- eliminate the diabetes, eliminate the hemophilia, reduce the risk of cancer? Who doesn't want healthier children? And then, that same analytic technology, that same engine of science that can produce the changes to prevent disease, will also enable us to adopt super-attributes, hyper-capacities -- that better memory. Why not have the quick wit of a Ken Jennings, especially if you can augment it with the next generation of the Watson machine? Why not have the quick twitch muscle that will enable you to run faster and longer? Why not live longer? These will be irresistible.

And when we are at a position where we can pass it on to the next generation, and we can adopt the attributes we want, we will have converted old-style evolution into neo-evolution. We'll take a process that normally might require 100,000 years, and we can compress it down to a thousand years -- and maybe even in the next 100 years. These are choices that your grandchildren, or their grandchildren, are going to have before them. Will we use these choices to make a society that is better, that is more successful, that is kinder? Or, will we selectively choose different attributes that we want for some of us and not for others of us? Will we make a society that is more boring and more uniform, or more robust and more versatile? These are the kinds of questions that we will have to face.

And most profoundly of all, will we ever be able to develop the wisdom, and to inherit the wisdom, that we'll need to make these choices wisely? For better or worse, and sooner than you may think, these choices will be up to us.

Thank you.

(Applause)