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Nicotine addiction and genes


pioneer
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I didn't read the paper, but I saw a news blip on CNN about scientist discovering some genetic factors that could lead to nicotine addiction, with these factors appearing in up to 50% of the population. If this is true, it has an interesting conclusion, that is subtle. If we apply modern evolutionary theory, nicotine consumption had a selective advantage. If it wasn't a selective advantage, according to the current theory, the rate should be much lower, since those genes would be bred out.

 

I am not for cigarette smoking, but using evolutionary theory, it is interesting to ponder why cigarette smoking created a selective advantage. Or, since we know cigarette smoking is not good for you, does this imply that selective advantage can also go to regressive genes?

 

One analogy of the latter, are a herd of deer having their mating olympics with the big buck winning. Based on the rules of the game, big dumb ox wins and medium smart ox is eliminated in the trials. What goes forward is big dumb ox genes. The progressive smart brain and smaller body genes don't get into the gene pool due to the way the rules of the game are set up. Getting back to nicotine, somehow the big dumb ox genes had selective advantage due to the rules of the game. Or if the rules were optimized does smoking cigarettes represents some type of genetic progression?

 

The third scenario is cigarette smoking, was an environmental potential leading to an almost global change in genes. What we are seeing is genetic adaptation to a potential. This is harder to prove since the science is not that advanced yet. The necessity with empiricism would be the need to observe molecular change in situ within a dynamic system, which is not easy to do. At the same time, logic is not part of the empirical tool kit, where that of itself is sufficient.

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It's more about the nicotinic receptors and NT interactions, and how those are somewhat different based on genetics. These genetic differences seem (at least, in part) to lead to a different reaction/experience during the first ever smoke, and then further, as a result of the pleasantness/unpleasantness of that first smoke, a different likelihood for future continuance of smoking behavior (did you get high or did you get sick the first time you tried smoking... it could be related to your genes). I'm always apprehensive to deal with people who begin, "I haven't actually read the paper or sought any solid information about this topic, but here's what I will speculate is causing it..."

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If we apply modern evolutionary theory, nicotine consumption had a selective advantage. If it wasn't a selective advantage, according to the current theory, the rate should be much lower, since those genes would be bred out.

 

unless people generally die of lung cancer after they've bred, in which case it would be relatively neutral, or it's mass smoking is simply too recent a phenomena to have had a noticeable effect yet.

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I was just applying evolutionary theory. If it was about animals with 50% of them having genes for a streak of white fur, then we would say see, this is evolution at work. But when the same thing gives us the result we don't want we are not ready to accept the theory. Since we know smoking is not healthy than it would imply even regressive behavior, with obvious disadvantages can evolve into genetics. This could explain why evolution is so slow. It doesn't have to forward the best.

 

On the other hand, cigarette smoking is relatively new in terms of mass appeal, as a result of modern manufacturing and marketing. This could indicate the rate of genetic change was quick and it happened almost globally, even in those with little history of cigarette smoking. The third option is nature has an instinct for other natural products of the earth. Perhaps the affect is more based on natural moderation with certain natural products part of human diversity.

 

The fourth option is because empiricism is so flexible, in terms of getting anything you like, because it does not have to rely much on logic, this study had a goal in mind, which is the selling of a medical test to determine who has the genes. They may already have the test or medicine, they just need to create the market. The cigarette manufacturers do their own studies and get what they want, too. They could use evolutionary theory to interpret this as natural evolution with selective advantage. I should not be so suspicious, so I was thinking in terms of many possible logical alternatives.

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There have been only 20 or so generations since the introduction of tobacco to the old world and even fewer generations since the onset of widespread use of tobacco products. That is hardly enough time for a genetic mutation to have appeared and spread. The obvious explanation is that the genetic propensity for nicotine addiction was already present before the introduction of tobacco. Probably something very primitive, because even rats can become addicted to nicotine.

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I was just applying existing evolutionary theory. What this indicates is either nicotine has a natural benefit, which is why it became part of natural selection, or natural selection does not have to go to the best genes since the final result is less than optimum in terms of what we know is the progressive path. Maybe the social environment which had been pro tobacco for many generations led to genetic change. One way out there theory is the mind, due to social prestige adapted the genetics to needs of the social hierarchy. This would explain global adaption without the need of everyone having to smoke.

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I was just applying existing evolutionary theory. What this indicates is either nicotine has a natural benefit ...

What you are doing is misunderstanding and misapplying existing evolutionary theory. There is no connection between human evolution and tobacco. None. The genetic propensity to nicotine addiction is a by-product of some genetic trait that presumably was selected for evolutionarily, but this trait has nothing to do with tobacco per se. Proof: The trait most likely has been around for millions of years (animals other than humans get addicted to nicotine); widespread use of tobacco products is 400 years old.

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from what i remember, niquotine is addictive because it's an analogue to a neuro-regulator.

 

pioneer, what indicates a selective benifit to tobacco addiction? the 50% allele frequency of these factors that contribute to tobacco addiction?

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  • 3 weeks later...

There are of course genes which predispose to nicotine addiction; those ones are related with nicotine receptors and with dopamine.

But nicotine receptors have not evolved in our body with the purpose to interact with the nicotine of the tobacco. They have evolved to interact with our own neurotransmitter acetylcholine and so to carry out its function.

 

On the other hand, the tobacco plant has found an evolutive advantage imitating the effect of acetylcholine in its interaction with nicotinic receptors.

As DH has indicated Europeans have been in contact with tobacco for about 20 generations, while the acetylcholine has acted on nicotinic receptors for millions of years…

 

Regarding dopamine, this neurotransmitter and its receptors are implicated in the addiction to all drugs, because it’s the neurotransmitter of the reward system. Genetic variations in this neurotransmitter or its receptors will lead to different tendencies to drug addiction.

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  • 1 month later...

Studies have shown that since the time when stringent smoking bans came into effect in the US, the number of emergency room asthma patients reporting to hospitals have decreased considerably. This study was conducted by the University of Kentucky and the results are after Lexington banned smoking in the public places. http://www.chantixhome.com

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  • 3 weeks later...

One possible explination for this is that the gene that makes people more vunerable to nicotine could bo co-inherited with a gene that was of benifit to the evolution of man. Another explination is that this gene lay dormant or un-noticed untill research was done into the genetics of nicotene addiction, as it presented no positive or harmfull characteristics to the individual pr population.

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It could be possible for genes to be inheriting how much a person may smoke. But what if quitting was in genes too? likely. If there is a gene that makes the person not affected by nicotine addiction, we may know what is really causing alot of this. Mainly, we should just stop selling all this stuff.

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