A new study has revealed that smoking leaves its mark on the genetic code by changing the chemical code of the DNA molecule, which may sometimes lead to a change in gene activity. The researchers found that some of these changes in the molecules return to their original state when you quit smoking, but some continue in the long term. Said Dr. Stephanie J.. London, who led the study team, a head of the Department of Epidemiology at the National Institute of Environmental Health Sciences in North Carolina, said that experts have known for some time that smoking causes changes in the DNA molecule, but they are now discovering more about the scope of these changes and what might they mean. The London Speaking of one of the media, "we do not really know if she meant damage to the DNA. Needed for further studies and use than those available data we have." The researchers collect data from 16 groups subject to search in a previous study on aging, and increased the number of participants in the study on 15 thousand people gave blood samples were analyzed to see if there has been a DNA change known as "DNA methylation." It features a DNA molecule to grow and develop guidelines, in the form of genes. And it can identify the so-called methyl groups on the surface of the molecule (the atoms of hydrogen and carbon) any genes that can be activated. The researchers make a comparison between the 2433 smokers said they smoked once a day at least during the last year and 6518 are a smoker quit smoking one year ago at least draw blood samples and 6596 did not smoke at all. The researchers found that smokers had 2623 different sites in genes which hydrogen atoms spread and carbon (methyl groups) compared with non-smokers. Ruby said Johanns, who led the study and works at the Harvard School of Medicine in Boston, said that this means the possibility of their 7000 Jane damage related to different types of cancer, high blood pressure and other health effects of smoking. He added that there is a need for further studies in the future to determine the relationship between DNA changes and the incidence of a number of diseases.