New study on obesity genetics

An interesting new paper has come out recently, reviving discussion of the effects of "nature" versus "nurture" in the development of obesity. Certainly everyone knows someone--or perhaps, is that someone, who can sit down and finish off an entire pizza without gaining an ounce, while others of us tend to gain weight just from looking at food. How much of our weight is due to our eating and exercise habits, and what's due to our genetics?

Anyone who even browses the health section of their local paper or online news source (or really, anyone who's not been living in a cave for much of the previous decade) knows that the "obesity epidemic" in America has gotten a lot of attention. We're fatter than ever before. This fatness is generally measured by calculating the body mass index (BMI), a fairly crude measurement taking your weight distributed over your height (find out yours here). A BMI of 25 or above is generally considered overweight and increases the risk of death from a number of conditions, while BMI over 30 is considered "obese." Currently, it's estimated that almost 2/3 of Americans are classified as "overweight," with 30% falling into the "obese" category.

Now, to be sure, BMI isn't necessarily the best measure of obesity. Imagine two people who are both 5'10". One is a couch potato and has a high body fat percentage; the other is a muscular athelete. Both weigh 200 pounds. This gives them both a BMI of 28.7, in the "overweight" category, although the athelete has a very low body fat percentage. This is why BMI data should be taken with a bit of caution--there's the potential for misclassification bias (essentially, putting people into the wrong category based on BMI data--such as the muscled jock in the "overweight" category). But overall, it's a useful proxy.

In the new study, the authors looked at a number of single nucleotide polymorphisms--"SNPs." These occur when just one of the bases in the genome is altered--say, from a C to a G. Though many SNPs are harmless as far as we can tell, some are associated with disease. (This doesn't necessarily mean they cause disease, but some of them do result in changes in the amino acids encoded by a DNA segment--and hence, the protein produced by the gene). Others may simply serve as a marker for a region associated with a higher likelihood of disease, but may play no role in the disease itself. Like so many areas in biology, it's not black and white.

Previous research has identified genetic regions associated with an increased rate of obesity. However, a common problem with many of this previous research was that it wasn't able to be replicated--initial findings didn't hold in a different study population. That's where this new paper differs. The authors initially screened over 100,000 SNPs in individuals that took part in the Framingham Heart Study (FHS): a study that began in Framingham, Massachusetts way back in 1948 to investigate, as the name suggests, heart disease. Since that time, children and even grandchildren of the initial participants have also been enrolled and followed. The investigators for the current study took participants from this study, analyzed their SNPs, and looked to see which were most predictive of increased BMI in their offspring. They found one SNP--designated rs7566605 CC--that was a significant predictor of BMI. Homozygotes (those who had 2 copies of the SNP) were on average about 1 BMI unit heavier than those with other genotypes, and were also likely to be obese (OR=1.33, 95% CI=1.20-1.48). Overall, the SNP was found in about 10% of the population.

An interesting finding by itself, but the authors didn't stop there. Rather than wait for others to replicate their findings, they used samples from a number of different studies in order to test whether the assocation between the SNP and BMI held up in populations other than the FHS cohort. In fact, they used samples from 5 other studies: the KORA S4 cohort, a German population; a case-control study of Caucasian subjects from Poland and the US; the Nurses Health Study; another study examining obesity in a parent-child cohort; and samples from an African-American population from Illinois. In all but the Nurses Health Study, the finding that the SNP under investigation was associated with increased BMI was replicated. (In the Nurses study, it's worth noting that there were fewer subjects with high BMI in that study than in the others they examined.)

Again, this finding doesn't mean that the SNP they identified causes one to be heavier. Rather, they explain that the SNP is about 10,000 base pairs upstream of another gene involved in fat metabolism, INSIG2 (insulin-induced gene 2), which encodes for a protein that inhibits the synthesis of fatty acid and cholesterol. This gene has already been implicated as a genetic factor in obesity in a previous study in humans, as well as a study using a mouse model, so it's likely that this SNP may be just a genetic marker for polymorphism in the INSIG2 or other genes in the region.

Finally, this doesn't mean people who have this mutation can just sit back, eat potato chips, and say, "hey, I'm destined to be fat." Depending on the study, estimates of heritability of BMI--in other words, how much of your weight is genetic versus environment--range from around 30-70%, so genetics certainly isn't destiny. It can, however, make it much more difficult for many of us to maintain our weight. Perhaps down the road we can specifically target some of these genes, in order to bridge some of the gap for those of us who seem genetically inclined to a higher BMI. Until then, the ol' diet and exercise gig is still the best route to maintain a healthy weight.

More like this

No access to the article for just fascinated peoples...sigh. I hate journals.

Anywho. Do the authors hypothesize this SNP is in one of the activation/regulatory sites for INSIG2? If so it's very curious this SNP changes in so large a population. Do they provide any hints for future research directions into why this area is suseptible to SNPs?

I can send you the .pdf if you drop me an email.

As far as your questions, they don't directly suggest the SNP is in a regulator, but say "A model in which altered insig2 activity leads to obesity by elevating plasma triglyceride levels with subsequent storage in adipose tissue is certainly plausible." They don't mention future studies.

Not to be too simplistic here, but if you are fat:

1. Eat less
2. Exercise more

Sorry, there ain't no "fat genes."

Hank Barnes

By Hank Barnes (not verified) on 17 Apr 2006 #permalink

Hank, sometimes I wonder if you really believe anything you write, or if you just disagree for the sake of disagreement.

"Sorry, there ain't no "fat genes.""

How do you know that, Hank? Have you done the science?

GE

By Guitar Eddie (not verified) on 17 Apr 2006 #permalink

Thanks Tara for the nice summary. My PhD thesis involved genetic epidemiology of chronic diseases, and I don't think I could have described the study any better.

Hank, I think that you are missing the point of genetic epidemiology in general. Tara already anticipated your comment and stated, "Finally, this doesn't mean people who have this mutation can just sit back, eat potato chips, ...". The point of identifying risk factors for a disease/condition that are associated with genes is not to replace other non-genetic risk factors (i.e. over-eating, physical inactivity, etc.). The reality is that there is plenty of variation in the observed world that isn't explained by existing factors, such as caloric intake and physical activity, and these unknown sources of variation are what the genetic epidemiologists are trying to discover. Learning about the unknown simply adds to the known, it doesn't necessarily mean that what we previously knew was false. As Tara stated, we all know people that can eat a lot and not gain weight even though they are not any more or less active than the typical person. We also know that some people may be more or less motivated to "eat less, exercise more". Genes that impact behavior might be particularly important for obesity (i.e. imagine someone for which eating sets off feelings of ecstasy while exercising fails to produce a "runner's high", it could be expected that such individuals might have a greater likilihood of becoming obese, than some with no joy from eating and a massive "runner's high").

This equation discribes the situation:
OBSERVED REALITY = KNOWN_VARIATION + UNKOWN_VARIATION(or ERROR).

Pretend that KNOWN VARIATION = 20% and ERROR = 80%, if science finds a gene that describes another 10%, then error goes down and known variation goes up.

Why is this important? We can only intervene on known variation, so the more known variation we can explain, the better we can treat the disease. Therefore, what I am trying to say is that new discoveries don't make old knowledge about "1. Eat less, 2. Exercise" any less true, but instead add to the potential tools in the toolbox. I think that we should all be able to agree that telling people to "eat less, and exercise more" might work for some people, but for whatever reasons it isn't particularly helpful for a lot of people.

Thanks again, Tara, for the post. I just found your blog, and I am looking forward to reading more from you.

Nice post. I think its pretty impressive that they were able to replicate their association in other populations.

I find it amusing that despite the only 1 BMI point difference between the populations of those who have two copies of this allele and those who don't, it will be trumpeted across the press and pop culture as a gene that 'makes you fat'.

*smacks head against brick wall*

I can lose (or gain) a BMI point in a day.

Hank is right in that a gene can't 'make you fat'. Simple laws of thermodynamics here.

Genes can influence your basal metabolic rate, insulin response, nutrient uptake, and response of metabolism to exercise, to name a few. But at the end of the day one must consume more calories than one expends in order to gain weight. While that may be a harder proposition for some than others, the genes themselves cannot make you fat

No, genes can't make you fat. They can, however, profoundly affect how much attention a given person has to pay to the problem to avoid becoming fat in modern society. One person can simply eat as much as they feel like eating of whatever they feel like eating and remain thin, while another person has to religiously watch diet and exercise to stay thin, frequently eating less than is satisfying and having to endure hunger with palatable food easily available.

That doesn't mean the second person has no control over the process, but hunger is a really powerful motivator (for reasons that seem tolerably obvious, evolutionarily speaking) and the number of people who can consistently make a decision not to eat when they're hungry and food is around seems to be small.

I'm not sure what IndianCowboy is implying. So what if genes by themselves cannot make you fat? Hank and the Cowboy seem to have difficulty understanding that cause and effect is not always simple. Not all causes are sufficient (i.e. by themselves they cause an effect) and not all causes are necessary (i.e. they have to be present or an effect can't occur). In order to have a car accident you must have a car involved, but just having a car doesn't cause accidents (i.e. the car is necessary, but not sufficient). Consuming alcohol, driving over the speed limit, having dementia, driving near a bar at closing time, etc. might all contribute to the likelihood that a car accident could occur, but any or all of those factors could very well be either present or absent in any one particular car accident. So too could a particular genetic predisposition be present or absent in a person with obesity. Just as staying away from cars isn't the only way to reduce or risk of being in a car accident, reducing your food intake or increasing your physical activity may not be the only ways to reduce your risk of obesity. This argument sounds a lot like the rationale for why abstinence only sex education is the ONLY way to prevent unwanted consequences (I think that both abstinence only education and focusing only on caloric intake/output are both destined to fail in a large portion of the population).
Also this isn't just simple thermodynamics. Such a statement implies that if I eat 10,000 calories and burn 900 calories I am bound to gain fat. This isn't the case, since I could be a person who excretes a high amount of calories in my waste. Some people excrete higher levels of sugars and proteins in their urine and other excrete feces with a lot of calories. In fact a common drug for weight loss prevents fat from entering the bloodstream. Cowboy even mentions some of these complex pathways just after saying this is simple.
Frankly, the whole issue of looking at obesity is a bit of an oversimplification, since some seem to tolerate higher levels of obesity without ill health effects than other people.
With regard to 1 unit of BMI being a small effect size, this should not be surprising. This study is looking at a difference in 1 SNP out of the entire genome. A complex trait like obesity is likely to be controlled by dozens if not hundreds of genes with each gene having many locations that if altered may impact the gene effects. On top of this there are gene-by-gene interactions and gene-by-environment interactions (ex. some mutations may regulate to fat metabolism, so these mutations may only have effects when with a high fat diet, other mutations might related to energy released with activity, the possibilities are staggering).
The moral of the story is that if you want to blame a fat person for being fat go ahead and tell them that if only they would eat less and exercise more than things might change. If you actually want to make a different in understanding why it is so much harder for some people to do this than others, then understanding a little genetics probably will help.

Hank, sometimes I wonder if you really believe anything you write, or if you just disagree for the sake of disagreement

Of course I believe what I write! And, when I agree with you, I'm the first to say so. We agree the small pox vaccination worked magnficently, don't we?

Genes cannot make you fat, sorry. There is no "fat" gene!

Eating a sheet cake for breakfast or a side order of 3 cheeseburgers with every meal will certainly make you fat.

Now, it's true, some folks are "big-boned" -- I agree, in principle, with this crude description. But, that ain't fat -- fat is fat. Too much adipose from too many sweets and too little exercise.

Eat a salad, take a few walks around the block, you'll be fine.

Hank B

By Hank Barnes (not verified) on 17 Apr 2006 #permalink

Hank, your oversimplification is easily disproven by a simple experiment -- one which is seen in reality every day. Two people, similar builds, similar diets, similar activity levels. One is obese, the other isn't -- may even struggle with needing to *gain* weight. The input (diet and exercise levels) is the same; the output (overall weight) isn't. How does your hypothesis explain this?

And remember, you can't just say it doesn't happen; everyone reading this will have been familiar with at least one real-life example, so you will merely look a fool if you take that tack.

Yes, of course diet and exercise are major influences on one's weight. The point of the article, which seems to have flown right past your rose-colored glasses, is that they are not the ONLY such influences.

Don't lump me in with Hank so fast there, guys.

First off, Dr. Smith, I liked the use of quotes around 'epidemic' and the fact that you didn't try to over-dramatize the finds as many researchers are wont to do. Such objectivity and value-neutral statement of the facts is commendable. I found it exceedingly refreshing.

I'm not denying the influence of these genes on one's ability to maintain a certain weight. I'm not even denying the size of their influence, but oen thing that bothers me is that many researchers, bloggers, reporters, whatever impute more into the findings than they should.

The use of the word 'epidemic' is a perfect example. If it really turns out that that one virus causes most of the obesity in America, then we've got an epidemic. If it's a matter of inherited tendency to retain a few more pounds than someone else, it's a different matter entirely.

Furthermore, as has been pointed out before, genetics seems to explain only about half the story. And as this study shows, we're not seeing dramatic differences in BMI at the population level. You can achieve significance without a large magnitude of effect.

But I guess the rest goes toward not the science so much as what it means for culture. You already here people say 'its genetic' or make other excuses, then trot out the science that can be twisted to mean that.

There's a great quote I wish I had readily available that said something like 'one must remember that most medicine is treated by the body as poison, it is therefore imperative that we limit its use to only when absolutely necessary.

To go along with that, I read a recent study that showed that taking one ambien was equivalent to smoking a certain number of cigarettes. Yet ambien is one of hte fastest growing prescriptions in America.

I was something of a lay psychologist/big brother-type in my younger years, and probably the one thing I dealt with more frequently than anything else was body image disorders. I've heard it was 'society's fault' for years, and I'm not going to deny the influence of society at all. But I always told the girls I was working with that it wasn't society's fault. Ultimately they chose to listen to the message they thought society was giving to them.

I didn't blame them, because i'm not an asshole and because they, like me, were still teenagers. But I did try to instill in them the idea that while they weren't at fault, it was their responsibility to filter those images out and ultimately their responsibility to develop a healthier outlook on life. And you know what? It was a very effective approach.

I fear the day that those of us who have it harder than others don't even try to make the effort. I fear the days of Harrison Bergeron are upon us.

Oh, another point. Has there been a correction applied to the BMI calculation since it was first proposed way back in 19th century Belgium?

I know that both male and female muscularity (dunno a better word to describe percent body weight that's muscle)has increased apppreciably in the past 30-100 years. So wouldn't one have to correct for this either by chanigng the constant in the equation or the bounds of each weight category?

What would happen if these 'overweight' and 'obese' people who aren't fat were removed from those categories? There are a LOT of males, for instance, that are currently classified as overweight, who really aren't.

And one final pet peeve. Doctors need to learn that BMI is only effective at the population level and can't be used as a proxy of body fat content at the individual level.

Sorry, 103 fever, I'm rambling now.

I don't get it. Why is there such hostility to the idea that obesity may have a genetic component? I fail to see where it's any skin off anyone's back, considering the fact that most all diease processes have a complex matrix of causalities.

I also noticed that people react the same way when the idea that drug addiction and alcoholism may have a inherent genetic component is broached.

Whose ox is getting gored?

GE

By Guitar Eddie (not verified) on 18 Apr 2006 #permalink

Guitar Eddie, people who are obese, or alcoholic, or drug addicts, are targets of derision.
There is a desire to believe that obesity, etc., is 'their own fault', and therefor, any suffering they go through, or any derision targeted at them, is what they deserve.

But no-one controls their genes. So, if obesity, etc., is caused by genes, it no longer seems to be 'their own fault'. Some other justification for the suffering and/or derision must be conjured up.

In case of drug addiction, people can go to prison due to drug possession. If there's a genetic component, and they have less control, is it still moral to put them in prison? We in the US have an enormously expensive drug war, which is focused mostly on locking up offenders. Wouldn't it be awful to learn that there was no moral justification for this expense?

In the small community of science-interested folk, it's common to think of multiple contributing causes (like Indian Cowboy's notion of obesity being influenced by both genes and behavior). But most people do not think that way. To them, it's black and white; either drug addiction is caused by genes, and the addict has no control, or it's the addict's choice, and they deserve to suffer.

The cow being gored is the belief that it is just to imprison drug addicts and fun to sneer at fat people.

I know that both male and female muscularity (dunno a better word to describe percent body weight that's muscle)has increased apppreciably in the past 30-100 years. So wouldn't one have to correct for this either by chanigng the constant in the equation or the bounds of each weight category?

There is no constant in the BMI equation. it's kg/m2. The categories are imperfect, but high BMI is associated with early death and cardiovascular disease, so there's something there.

What would happen if these 'overweight' and 'obese' people who aren't fat were removed from those categories?

That would probably increase the strength of the association, don't you think? Phenotypic heterogeneity (different phentypes being spuriously classified together because of their outward appearance, a problem with a lot of medical traits) tends to decrease the power to detect a genetic effect because the etiology, and thus the genes involved, is/are different. Remove the heterogeneity, strengthen the association.

"Guitar Eddie, people who are obese, or alcoholic, or drug addicts, are targets of derision.
There is a desire to believe that obesity, etc., is 'their own fault', and therefor, any suffering they go through, or any derision targeted at them, is what they deserve.

But no-one controls their genes. So, if obesity, etc., is caused by genes, it no longer seems to be 'their own fault'. Some other justification for the suffering and/or derision must be conjured up."

So, in other words, it's kind of a religious belief that people are trying to defend. And if they don't have any moral justification to deride or look down on someone, they would be disfunctional as people.

"In case of drug addiction, people can go to prison due to drug possession. If there's a genetic component, and they have less control, is it still moral to put them in prison?"

Of course not. And it never was to begin with. For in a society whose legal constructs are presumtive of civil liberty, the government has no justification for punishing people for what they do to themselves.

"We in the US have an enormously expensive drug war, which is focused mostly on locking up offenders. Wouldn't it be awful to learn that there was no moral justification for this expense?"
It would be awful for some the Manichaens of our society but not for those of us who operate on reason.The cow being gored is the belief that it is just to imprison drug addicts and fun to sneer at fat people.

"The cow being gored is the belief that it is just to imprison drug addicts and fun to sneer at fat people."

Wow. A really big loss.

No skin off my back, though.

GE

By Guitar Eddie (not verified) on 18 Apr 2006 #permalink

Man, either some folks are real naive or real dense.

Nobody's passing a moral judgment on being fat -- you can be kind, smart, generous, moral and still be fat.

Moreover, nobody's saying it's easy to cure fatness.

It's not. Sometimes its damn hard. I've eaten way too many pork-ribs, smothered in B-B-Q sauce, with healthy portions of baked beans, collared greens, and cornbread. MMMmmm.

But, the fact remains, the cause of obesity is: (a) too much food and (2) too little exercise.

And, this is important, because the effect of obesity, is a greater risk of heart disease, perhaps Diabetes II, and other maladies.

So, to reduce the risk of this unpleasant medical effect, cut out a few pepperoni pizzas.

This is so simple!

Hank B

By Hank Barnes (not verified) on 18 Apr 2006 #permalink

Hank, the problem is that doesn't apply to reality. I for one am fat. Overweight. my BMI is around 28, and it's NOT because of muscle. I'm fat and blobby and I have a hella hard time shifting the weight. Not just down, but up as well.

The thing is, I've gone through periods of eating badly, and periods of eating well, and periods of eating very little. I've exercised and eaten according to some pretty sensible eating guidelines consistently for years at a time.

And I don't shift from my weight. Like many, I'm like the skinny kid who eats all he wants or eats very little and always stays with his BMI of 20 - except I sit on my BMI of ~28 whether I eat horrifically, or whether I eat well. "Cutting out the pizzas" did nothing to make me lose, nor did reintroducing pizzas make me gain any more. I've hovered within 10lbs of my weight at age 18 for 20 years.

It's bad for my health certainly. It's pretty grotesque too, with extra annoying things like needing to make sure I wash in fat folds lest they get like 3-day old underarms - but the fact remains reducing my food intake and increasing my exercise, long term, does not lead to a weight loss. period. (It's lead to some level of malnourishment, though)

Eddie, you're confusing things a bit.

At least in my case I'm not hostile to the fact that obesity can be influenced by genetic factors. I tried to make that clear by pointing out that the way Dr. Smith presented the material is as exactly as it should be. But that she's in the minority in her lack of sensationalism.

What I'm hostile to is the idea that genes can MAKE you fat. What I'm hostile to is the fact that I fear researchers, doctors, and the media will spread a message that people can do nothing on their own to prevent becoming obese.

What I'm hostile to is normal human variation becoming characterized as disease.

What I'm hostile to is loss of empowerment and externalization of responsibility.

What I'm hostile to is genetic determinism.

Furthermore, genes have some influence on many, many aspects of behavior, both detrimental and beneficial. If we're to take an attitude that if genes influence a certain behavior even a little, it's wrong to judge them morally then we'd be looking at a world where many things could no longer be considered crime and many dangerous people couldn't be locked up. (oh btw, i disagree with the war on drugs and think they need to be just straight up legalized)

Aggression has a genetic component. Would it be wrong to morally judge a man who brutally assaults another?

IndianCowboy,
I think that most researchers I know would agree with a lot of what you just said. The problems seem to enter when the media or others frame issues as having only 1 cause. Clearly, genes can contribute and dare I say act as 1 or many of the causes of obesity, but this does not mean that personal choices do not also contribute significantly to obesity. The same goes for the person with a genetic predisposition toward extremely abnormal sexual behavior (such as pedophilia) their genetic tendency or even their poor childhood experiences should not be used to completely absolve them of their responsibility to make lawful choices. Genetics shouldn't be used as a crutch for irresponsible behavior. The difficult thing is striking the right balance in assigning causes (or blame). This is a complex world that we leave in and assigning blame is both difficult and necessary in some instances, but this doesn't mean that we should pretend the world is simpler to understand than it really is. The current GOP movement has made progress with a lot of voters by pretending that the world is simple to understand if you think like them. Even if it feels better to leave in a pretend simplier world, I would argue that we should still strive to understand as much of the complexity as possible.

"What I'm hostile to is the idea that genes can MAKE you fat. What I'm hostile to is the fact that I fear researchers, doctors, and the media will spread a message that people can do nothing on their own to prevent becoming obese."

I find somewhat unlikely that the scientific community would disseminate that message. If any scientist did, he/she would be out of a job. As regards the media, the answer is to have more journalist who are scientifically literate to reduce the likelihood that such a message would be sent to the public.

"What I'm hostile to is normal human variation becoming characterized as disease."

I don't think anyone is that the normal human variation is the disease. The disease is obesity. The scientist are just saying that one's genes contribute to how vulnerable one is to becoming obese.

"What I'm hostile to is loss of empowerment and externalization of responsibility."

It is the individual who either empowers or disempowers himself, not ones genes. Besides, externalization of responsibility be somewhat implausible considering that genetics is integral to one's biological existence.

"What I'm hostile to is genetic determinism."

That's good because genes do not operate deterministically. They operate probabalistically within a environmental context.

"Furthermore, genes have some influence on many, many aspects of behavior, both detrimental and beneficial. If we're to take an attitude that, if genes influence a certain behavior even a little, it's wrong to judge them morally then we'd be looking at a world where many things could no longer be considered crime and many dangerous people couldn't be locked up. (oh btw, i disagree with the war on drugs and think they need to be just straight up legalized)."

I don't buy that scenario, Indian Cowboy. For it's just as likely that the violent and antisocial behaviour could be treated medically. We would still have to take the dangerous people off the streets in order to treat them.

I, too, agree that war on drugs needs to be ended. But we also need to have an infrastructure in place so that bad effects of drug use can be rendered harmless to the rest of society.

"Aggression has a genetic component. Would it be wrong to morally judge a man who brutally assaults another?"

Of course not! But understanding the genetic component of aggression could help find a more effective way to deal with the problem of a man who brutally assaults another. To paraphrase Gandhi, merely taking an eye for an eye only makes more people blind. It help the violent person to change himself.

GE

By Guitar Eddie (not verified) on 19 Apr 2006 #permalink

obesity is NOT a disease. every detrimental health effect is an indirect result of obesity. I covered this in a blog post a few days back. The process of becoming obese is a normal physiologic response to excess calorie consumption. Genetics may influence how little food it requires to create an excess, but they only indirectly affect obesity.

Obesity doesn't directly hurt you. It is not in and of itself a disease. High cholesterol, high triglycerids, type II diabetes, etc, are all correlated. These are the actual causes of disease.

Guitar Eddie,

unless reporters are fudging quotes, researcher sensationalism is all over the place. Just go to news.yahoo.com, www.livescience.com, and www.sciencedaily.com

And if we start to tamper with those genes, despite population level differences that aren't that big and levels of penetrance that arne't THAT great, we'll be essentially saying those genes are disease-state alleles, ignoring the fact that in most cases, behavioral change can do a lot more.

i'm not sure if you're trying to misread me intentionally or not in your next comment. My point was that with all the 'genes make you fat' nonsense floating around, people will become disempowered. They will believe they can do nothing. And with the next part of your point, you're just being obtuse. Externalization of responsibility, as I'm sure you know I meant in this context, means blaming factors OUTSIDE YOUR CONTROL, which your genes are.

And your next comment. THat's my entire point, genes operate probabalistically yet they're popularly conceived of in a deterministic fashion. Somethign that isn't being helped by a lot of researchers.

"And if we start to tamper with those genes, despite population level differences that aren't that big and levels of penetrance that arne't THAT great, we'll be essentially saying those genes are disease-state alleles, ignoring the fact that in most cases, behavioral change can do a lot more."

Sounds like a personal problem to me.

And how do you know behavioural change is the solution in most cases. Have you done the science to back up that assertion? Are you an obesity researcher or just an ordinary schmuck like the rest of us?

"i'm not sure if you're trying to misread me intentionally or not in your next comment. My point was that with all the 'genes make you fat' nonsense floating around, people will become disempowered."

I don't think I am misreading you, Cowboy. There always some idiot wind blowing through our society; and only the ignorant allow themselves to be blown by it. That's why we have scientists and teachers who can dispell the nonsense if we'd allow them to.

"And with the next part of your point, you're just being obtuse. Externalization of responsibility, as I'm sure you know I meant in this context, means blaming factors OUTSIDE YOUR CONTROL, which your genes are."

Obtuse? Hardly. I understood what you were saying. Besides, if one's genes are out of his/her control, then those who externalize responsibility are only partially wrong. Externalization of things seems to be part of human nature. Afterall our culture promotes belief in an external, personal god and an anthropomorphic evil (Satan), further reinforcing that kind of thinking.

"And your next comment. THat's my entire point, genes operate probabalistically yet they're popularly conceived of in a deterministic fashion. Somethign that isn't being helped by a lot of researchers."

Unfortunately many scientific researches are highly skilled at research but have inadequate skill at communications, meaning that they communicate their findings but are naive about how the public will understand them. It isn't the message, it's how the message is heard. Relatedly, we can thank the media for the popular conception of genes being deterministic. From their point of view it is more entertaining to say "genes cause this or that problem" than it is to say "genes make it more or less likely that a person will develope a certain disease. It's easier to get across to people who are essentially illiterate about science.

GE

By Guitar Eddie (not verified) on 23 Apr 2006 #permalink

i don't know if this was mentioned in the long comments section, but i tend to distrust results of this sort. the commonly known reason is the 'gene' while supposedly 'near' one supposedly 'involved' in fat metabolism, the genetic connection may differ. for example, many have suggested that the 'female' gene is correlated with 'uncommon success' in 'science', but this may not have to do with the effects of that gene on science ability, but because it serves as a marker for social transmission of behavior. similarily a society where 'books' are always on a 'high shelf' may find that 'short people' (which is somewhat hereditary, though even that is questionable since diet is heavily involved) will turn out to be 'illiterate.
i think they have to show the gene is involved in metabolism rather than in some of other features of people who may turn out to be more likely to become obese.

i don't know if this was mentioned in the long comments section, but i tend to distrust results of this sort. the commonly known reason is the 'gene' while supposedly 'near' one supposedly 'involved' in fat metabolism, the genetic connection may differ. for example, many have suggested that the 'female' gene is correlated with 'uncommon success' in 'science', but this may not have to do with the effects of that gene on science ability, but because it serves as a marker for social transmission of behavior. similarily a society where 'books' are always on a 'high shelf' may find that 'short people' (which is somewhat hereditary, though even that is questionable since diet is heavily involved) will turn out to be 'illiterate.
i think they have to show the gene is involved in metabolism rather than in some other features of people who may turn out to be more likely to become obese.