Saturday, July 31, 2010

Venter on the human genome

Here's an excerpt from an interview with geneticist Craig Venter:
SPIEGEL: Nevertheless, Jim Watson, the co-discoverer of the DNA double helix, has said he doesn't want to know which variant of the so-called ApoE gene he has -- it could say something about his risk for developing Alzheimer's, and he's afraid of that.

Venter: That was silliness. At that age? Watson is over 80.

SPIEGEL: Are you interested in finding out what ApoE variant you have?

Venter: I know it. And according to it, I have a slightly increased risk for Alzheimer's disease. But it impresses me little because I could have dozens of other genes that counteract it. Because we do not know that, this information is meaningless.

[. . .]

Venter: Look at this bottle that you have touched -- that's all I need to obtain your entire genetic information.

SPIEGEL: How much would you be able to learn about us by doing so?

Venter: If anything, we don't really know how to read the genome and it can't tell us very much right now. So what's the ethical debate about?

SPIEGEL: The decoding of your personal genome has so far revealed little more than the fact that your ear wax tends to be moist.

Venter: That's what you say. And what else have I learned from my genome? Very little. We couldn't even be certain from my genome what my eye color was. Isn't that sad? Everyone was looking for miracle "yes/no" answers in the genome. "Yes, you'll have cancer." Or "No, you won't have cancer." But that's just not the way it is.

SPIEGEL: So the Human Genome Project has had very little medical benefits so far?

Venter: Close to zero to put it precisely.

SPIEGEL: Did it at least provide us with some new knowledge?

Venter: It certainly has. Eleven years ago, we didn't even know how many genes humans have. Many estimated that number at 100,000, and some went as high as 300,000. We made a lot of enemies when we claimed that there appeared to be considerably fewer -- probably closer to the neighborhood of 40,000! And then we found out that there are only half as many [i.e. humans have a little over 20,000 genes]. I was just in Stockholm for the 200th anniversary of the Karolinska Institute. The first presentation was about the many achievements the decoding of the genome has brought. Then I spoke and said that this century will be remembered for how little, and not how much, happened in this field.

SPIEGEL: Why is it taking so long for the results of genome research to be applied in medicine?

Venter: Because we have, in truth, learned nothing from the genome other than probabilities. How does a 1 or 3 percent increased risk for something translate into the clinic? It is useless information.

SPIEGEL: There are hundreds of hereditary diseases that can be traced to defects in individual genes. You can determine a lot more than just probabilities through them. But that still hasn't led to a flood of new treatments.

Venter: There were false expectations. Take Ataxia telangiectasia, for example, a horrible disease. The nervous system degenerates, and people who have it often die in their early teens. The cause is a defect in a single gene, but it is a developmental gene. If your body is built in the wrong way, then you can't just take a magic pill to rebuild it. If your brain is wired wrong, then it is wired wrong.

SPIEGEL: Who is to blame for those false expectations?

Venter: We were simply always looking at single genes because they were the only genes we had. When people lose their keys at night, they look under the lamp post. Why? Because that's where you can still see something.

SPIEGEL: But the keys are really located in the dark?

Venter: Exactly. Why did people think there were so many human genes? It's because they thought there was going to be one gene for each human trait. And if you want to cure greed, you change the greed gene, right? Or the envy gene, which is probably far more dangerous. But it turns out that we're pretty complex. If you want to find out why someone gets Alzheimer's or cancer, then it is not enough to look at one gene. To do so, we have to have the whole picture. It's like saying you want to explore Valencia and the only thing you can see is this table. You see a little rust, but that tells you nothing about Valencia other than that the air is maybe salty. That's where we are with the genome. We know nothing.

SPIEGEL: Do you think there will be a time when you can extract all this information to yield real medical results?

Venter: For that to happen we need a lot more information: Information about your body's chemistry, your physiology, your complete medical history, your brain and your entire life. We would need to do that a million times on different people and correlate that data with their genetic information.

SPIEGEL: Will that lead in the end to the kind of personalized medicine that genetic researchers have always touted? Each person would get his or her own personal treatment that is tailored precisely to that person's genetic make-up?

Venter: That was another one of these silly naïve notions that was out there. It's not, "Oh, we know your genome, we're going to make this drug for you." That will never happen. It is more important that you use the information in the genome about your personal risks and reduce them through intelligent behavior.


  1. Thanks Patrick for posting this!

    I've looked at so many Genome headlines that it seemed like the hype was true.

    This puts the whole thing in perspective.

  2. It's refreshing to hear from an honest scientist.