Название | Masterminds: Genius, DNA, and the Quest to Rewrite Life |
---|---|
Автор произведения | David Duncan Ewing |
Жанр | Прочая образовательная литература |
Серия | |
Издательство | Прочая образовательная литература |
Год выпуска | 0 |
isbn | 9780007390588 |
“Look at the literature about science,” he says. “What was the significance of Mary Shelley’s Frankenstein? Why was Frankenstein considered an important book? Certainly not in the same way we think of Harry Potter as some kind of cheap science fiction. It wasn’t just science fiction. It was, in my view, because it addressed what is the essence of being human.
“So this relates to—if I can get this back to where I started—we were talking about ES cells and why the nation is so excited about where they come from. This issue is one that I have of necessity delved into quite a bit. It would take too long to talk about the various religious views of why one should isolate ES cells and not and whether cloning should be allowed.”
“Have you written about that?”
“No, but I have to talk publicly about it often, like with Catholic priests and with the Board of Overseers of Harvard. So I actually have educated myself quite a lot on the various religious views. I don’t really want to get into it, and the reason is I don’t think it’s fundamentally interesting. It largely has to do with the trivial concern of trying to put a tag on when life begins. What I do think is deeply interesting is this issue of chimeras. So bear with me for a minute on a couple of very broad themes that I think human ES cells opened the door to.”
I nod as he shifts from biologist to impassioned philosopher.
“Let’s say that, at a minimum, there are two areas of behavior in which our government spends an enormous amount of money. Both of them indirectly struggle with the question of whether phenotypes for the final product is a consequence more of nature or more or nurture. One of these is public education. So if you think about the whole philosophy of it, the idea which I think is a commendable one is that everyone has equal potential, and given equal opportunity will produce results. The other has to do with criminal behavior. I heard on the news this morning that for the first time now, two million people—one percent of our population—is incarcerated. It’s a number I find fascinating.
“In the book Madness in Civilization, by Foucault, he says that one way to characterize a society is to hold a mirror up to it. And that mirror is, who does the society contend is nuts? It’s a very interesting thesis. You learn more about the reflection of a society not by talking about their kings and queens and the middle class, but whom the society is fearful of. Because that defines them in a way. So if you were to accept this—and I can think of better examples—that the government spends wads of money addressing indirectly this question of nature and nurture through incarcerating people. Now, is this our genotype driving this, or our environment?
“Now bear with me as I tell you two kinds of experiments that will give hard numbers on what I’m saying. I’m not suggesting that this will answer the question. What I’m saying is it’s going to give hard, factual information that will be useful. So the first one is these identical twin studies done with humans that were separated at birth. I find that fascinating, principally because it says there’s more to the genes than you want to imagine.* And now let’s do an experiment where we clone animals so we have twins, genetically identical individuals. And let’s take an animal that has interesting behavior. It’s hard to argue that gorillas and/or chimpanzees don’t have behaviors that are very similar to humans.
“So that’s what I want my experiment to be. To clone gorillas or chimpanzees. It’s expensive, but that’s why I introduced it with the cost we spend on prisons. And now we have behavioral tests, and I don’t actually care what the tests are. In the identical twin studies, they were ‘what’s your favorite color?’ Which is a very interesting question because it’s so meaningless and stupid, and yet the fact that identical twins had an 80 percent correlation coefficient on that, even though they’d been separated at birth, I find fascinating. So let’s take gorillas. What do they like to eat better, bananas or mangos? How do they do that test? How did they do on visual acuity?
“So what you get as a result of that is numbers, hard numbers on the extent to which behavior is modified by a gene. Now, for the more interesting experiment. We take a human ES cell and we inject it into a monkey blastocyst [the first cells in a newly formed embryo]. Now you know that if you take a mouse ES cell that is, say, labeled so all of the developed cells will be blue, and you inject it into a mouse blastocyst, you’ll get a chimera where different parts of the mouse will be derived from the injected ES cell. So it might have a blue liver and some blue muscle cells, and that’s what I mean by a chimera.”
“That’s something you do today?” I ask.
“Yes. But now let’s do it with the human ES cells into a monkey, and we make chimeras. This is different from cloning now. We’re purposely trying to make a chimera—one hundred chimeras from one hundred monkeys. And now we’re going to look through their bodies and we’re going to look to see what parts of the body the human ES cell makes. Now, there’ll be a monkey where the only thing that was made that is human is the big toe. That’s completely uninteresting; no one will argue about that. No one will say that’s an experiment you shouldn’t do. And then we’ll have a monkey with a human heart. Three centuries ago, if we found a monkey whose heart was human, people would have freaked out because the seat of the soul was the heart. Now, no one really thinks that.”
He’s talking very fast now, and I’m trying to keep up, though I think he just said that no one would object to growing a human heart in a monkey. I consider this, and decide that I am okay with this in terms of trying to come up with, say, a heart for transplant into someone’s grandmother who will die because there currently aren’t enough hearts available. But Melton is already plowing ahead with his hypothetical experiment to create chimeras out of stem cells, and I’m wondering how far he will go with an idea that is already treading close in many people’s minds to Frankenstein territory with this talk about human toes and other body parts growing on, and inside, monkeys.
“But the brain is different,” he is saying. “These days, if we’re forced to pick a body part where our soul is, we say it’s connected to our mind, which is connected to our brain. And that comes back to this idea of what is natural, because that’s a relatively recent thing. So now, we have our hundred monkeys; one of them has a blue big toe; another one has a human heart. But now the interesting part of the experiment is that we can make chimeras which have different parts of our human brains, and different parts of a monkey brain.
“And one of the first level questions we might ask is, What part of a monkey has to be human in order to have speech?” He is very animated now. “I find it really intriguing, as in the movie Planet of the Apes, to walk into a lab here at Harvard and have one of the monkeys say to you, ‘Hello.’ That makes you wonder immediately, what does this monkey think? So what you want to first know, is this just mimicry, like a parrot? And it gets back to Wittgenstein, who talked about, what is the relationship between language and thought? So you ask me what am I excited about, that’s it.”
He pauses for air, and I tell him I was with him up to the point where the monkey is linking thought and speech. “I have to admit that this would give me the heebie-jeebies,” I say. “A human brain in a monkey that is conscious, it would be a horrible freak, worse than the Elephant Man.”
“I’m not suggesting that this chimera would have the intelligence of a human.”
“But how do you know it won’t?”
“It’s an interesting question; I find it highly unlikely that this would happen. I don’t think it would. There would be just parts of the brain that were human.”
“It still sounds potentially