IRA FLATOW, host:

And for the rest of the hour: The holy grail of genetics. Well, for some of us, at least, when we look in the mirror, you know, that person who can eat - there are people who can eat and eat and eat and never get fat. They can eat carbs, they can have dessert, they never go to the gym, and they never get fat. Why is that? Could genetics be at work?

Well, now, researchers at the University of Texas South Western Medical Center say they may, may be have found a gene that allow some people to eat and never get fat. The gene is found in - there's a whole range of animals, from nematodes to fruit flies to humans. So how does it work?

Joining me now to talk about it is Jonathan Graff, associate professor of developmental biology, University of Texas Southwestern Medical Center in Dallas.

Welcome to SCIENCE FRIDAY, Dr. Graff.

Dr. JONATHAN GRAFF (Associate Professor, Developmental Biology, University of Texas Southwestern Medical Center): Well, thank you so much for having me, Mr. Flatow.

FLATOW: Is this the holy grail of dieting?

Dr. GRAFF: Well, the holy grail would be eat more and weigh less. I suppose and in some ways, this can be. Yes.

FLATOW: How were you so sure?

Dr. GRAFF: Well, we have done studies in a wide range of organisms, going up the animal kingdom, from the seal against the nematode, fruit flies to mice. And if you reduce the activity of this protein, you get fat and, for example, get diabetes, if you're a mammal. But if we turn up the activity of this protein, you're thin and you can eat as much or more than your buddy.

FLATOW: Wow. Do we know how the protein is controlled then, what turns it up or down?

Dr. GRAFF: We're beginning to understand that, but that's certainly a key direction that you've identified for the future.

FLATOW: And how did you discover it?

Dr. GRAFF: We were doing screenings, that is trying to identify genes that control fat biology. And few studies had yet been directed towards understanding invertebrate fat formulation - that is in animals that don't have backbones or bones like fruit flies - and it was not clear if the tremendous strengths and powers of those models could be exploited to help combat the epidemic of obesity and diabetes.

And since these invertebrate models provide so many extraordinary advantages, we sought to determine if they were suitable models for fat biology and then to exploit them if they were to provide insights that may help people who suffer the negative consequences of obesity, diabetes and other conditions related to fat.

So we screen for animals - to find skinny or fat worms or skinny or fat flies, or for the altered function that is to be able to handle, for example, famine well. And we found a bunch, and one of them was this gene. And so we found out that it controlled fat biology in invertebrates, and now we moved up the animal kingdom to mammals.

FLATOW: So is it going to end up just being a matter if we can control the protein that the gene makes?

Dr. GRAFF: Right, right, so almost every - we, and unfortunately, that is the scientific biologic community, we sort of used genes from proteins interchangeably. But this helps us identify a new target for therapies. And most drugs that we take, for example, almost any drug that you or your listeners have ever taken, target the protein, that is alter the activity of the protein. So when you take aspirin, it works on a specific protein and alters its activity, so absolutely right.

FLATOW: So then this could be one gene that can - would it also control our craving for food or, if I hear you correctly, it controls what happens to the food after we eat it?

Dr. GRAFF: Correct. Well, there are genes that absolutely control our protein -should I say that absolutely control appetite, and some of those are made in your fat cells, go out in your blood and control your brain. This is different. This seems to control the efficiency of that storage.

So imagine, if you will - and I know you've done many shows on, for example, energy conservation. And one way we do it now is for - these new light bulbs that are more efficient, use less energy, or new air-conditioning units - this thing, protein, does the same thing. So it just sets our ability to use the energy either more or less efficiently.

FLATOW: Now, we keep hearing more and more information coming out about the health and nutrition and genetics. Let me remind everybody that this is TALK OF THE NATION: SCIENCE FRIDAY from NPR News. Talking with Jonathan Graff, associate professor of developmental biology, University of Texas Southwestern Medical Center in Dallas.

So where do you go from here? I imagine, you know, people are - what's more popular than talking about weight loss, you know, and obesity and the epidemic of obesity? You must be inundated with people who want to follow up on this.

Dr. GRAFF: It's been astonishing, the response. Hundreds and hundreds of e-mails, long-lost cousins, friends I hadn't heard off for 40 years, my mother even called me, saw me on TV.

FLATOW: And your stockbrokers are probably getting in.

Dr. GRAFF: Yeah, absolutely. My venture capitalists have called me because, of course, they want to start companies around this sort of notions. But, yes, it's been a tremendously important topic. I'm sure you know that there are - in I think, 2005, roughly the World Health Organization said that more than a billion and a half people were overweight, the projections are to be 2.3 billion by 2015. So this is an enormously important topic. And I guess in contrast to the book written by your last guest, this is a sort of the world with too much of us or maybe the world with a little less of us.

FLATOW: So tell us where you go now. How do you move your research ahead or make a product or what happens down the line now?

Dr. GRAFF: I think there are two avenues. One is to understand how this works, sort of the question you asked before, figure out the other proteins that works with how this machine controls the efficiency of fat storage or weight gain. And then the second is to screen to identify drugs that we would then, you know, of course, move into clinical trials and ultimately help people with diabetes and obesity.

FLATOW: It seems like this gene has been always been around so long, and you've just - you discovered something that was - I hate to put it this way - but seemed to be an obvious gene in everything that's living.

Dr. GRAFF: Well, I think it's, you know, you find what you search for. And we were searching for this kind of molecule and people hadn't necessarily tried to screen or identify them with the same methodology that we have.

FLATOW: So it was your methodology that allowed you to find this…

Dr. GRAFF: Well, I don't mean it in such a self-centered way, that is we were just scratching around for this kind of thing, and most people were scratching around for other things. And in addition, we're able to leverage off the power of genome projects - I know you've talked about in the past human - the human genome project. But these genome projects have gone on in a numerous organisms, from these worms to flies to mice. So we were just able to stand on the shoulder of giants to integrate information that was more available now than in the past.

FLATOW: One quick - last question. We know that diabetes has epidemic proportions, why are diabetes in the level of this protein link?

Dr. GRAFF: So - fat cells control the overall metabolic state of your body. That is if you have too many fat cells or too few fat cells, you can get diabetes. This protein, if you reduce its function, the mice or animals get diabetes. So we can use this as a tool to regulate blood sugar metabolism.

FLATOW: Thank you very much for taking time to be with us.

Dr. GRAFF: Well, thank you so much for having me as a guest.

FLATOW: And good luck to you. Jonathan Graff is associate professor of developmental biology - it is Friday - at the University of Texas Southwestern Medical Center in Dallas.

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