Thursday, July 05, 2007

Can Smokers be Wiped out by Natural Selection?

One interesting thought!! Can Natural Selection wipe out the smokers from the Earth after years of evolution? The study results point to a similar direction.

First of all, the smoking habit has to be a genetic characteristic (inherited property in other words) to be qualified to take part in evolution. Scientists, in fact, claim to have discovered the gene linked to smoking habit. The study by Dr Hidetoshi Nakamura of Keio University in Japan looked at a particular gene known to have an effect on how people process nicotine. In the human body, nicotine is mainly metabolized by the gene CYP2A6.If people are not very good at processing nicotine, then they are less likely to be interested in smoking and less likely to continue if they do start. In another study by Dr Robert Walton, of Oxford's clinical pharmacology department, variations of a gene known as the dopamine D2 receptor gene, or DRD2, reveals whether individuals are genetically programmed to be addicted to nicotine. One in three people is born with the gene.

Now let's see how the smoking habit can make us disadvantageous to reproduce. British researchers published a study claiming that a life of cigarette smoking will be, on average, 10 years shorter than a life without it. They also claimed that consistent cigarette smoking doubles mortality rates in both middle age and old age. More interestingly, Men who smoke cigarettes may experience a significant decline in their capacity to father a child, a research by a reproductive medicine specialist from the University at Buffalo indicates. Like other cells in the body, human sperm carry a receptor for nicotine, which means they recognize and respond to nicotine. The results could mean that heavy smoking overloads the nicotine receptor in human sperm and in the testes, leading to a decline in fertilizing potential. Not only that, the same study claims, smoking men also should be aware that smoking can damage their sperm DNA, passing on faulty DNA to their baby.

To sum up, smokers are likely to have less life-span with less probability to father (or mother) a child. If we bring together all theree studies, the platform for differential reproduction rate to wipe out a genetic variety seems to be in effect. Isn't those enough to stop spreading the genes for smoking? To answer in brief : No, as memes are there to manipulate.

This is where importance of memes comes to picture. Let's take an example of Indian women. They generally don't smoke because in Indian societies, smoking by women is almost prohibited. So, they carry the 'smoking gene' to pass it to the next generation as successfully as other women would have done. The smoking gene doesn't stop spreading because of the meme present in Indian societies to prevent women from smoking. The strong Indian social structure defies the Natural Selection on smokers. In a nature versus nurture debate, in this case, nurture seems to have won - and the habit of smoking will last longer in protective societies. To wipe the habit out, we require the introduction of a new stronger meme to stop smoking itself. The meme is: "Smoking is injurious to health" - and we need a strong awareness campaign.

Reference : Meme and it's activities (my old post)

Darwin, DNA, Evolution, Meme, Genetics, Science

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