Mark Twain used to note that giving up smoking is quite easy. He knew it as he had done it many times but each time was not the last attempt. It is much more difficult to give up smoking forever. Some people can easier get rid of nicotine dependence forev

It is interesting to note that some doctors are convinced that quiting smoking is just an issue of will power and nothing else. To the opinion of this small group of physicians theoretically each person can give up smoking. Only those people who are weak just can not make themselves do it.

This explanation is not supported by those scientists who regard the issue on the genetic level. For example Jacqueline Vink, a representative of the Free University of Amsterdam, tried to prove that smoking is closely connected to the genetics of each individual in particular. She used a special database - Netherlands Twin Register to watch the difference in smoking of twins. The study showed that the level of dependence upon nicotine and the quantity of cigarettes per day are connected with the genetics. Though Dr Vink has not taken into consideration the fact that the database allowed the comparison of identical twins with fraternal twins, it was quite an important study. In her work Dr Vink payed the attention to the adult fraternal twins, who had answered the questions concerning their habits.

By the way a human genome is a complicated and not enough studied issue. A genome includes a huge number of the so-called 'letters' that can sometimes make sense if brought together. Some of these 'letters' have no function or their function is not known. To explain the behavior of a person geneticists concentrate on special markers that were identified in each genome. These markers are places where the genetic letters may bare different character in dependence on a person. In case it is associated with a certain physical trait or a behavior feature it means that this genetic version is effecting that trait.

In her study Dr Vink has found 4 markers that are associated with smoking habit. According to the researcher's opinion this discovery will help in soon future identify the reason of nicotine dependence. And it will be in its turn a serious step forward.