They analyzed data from 46 previous studies and claim the analysis of over 20,000 people revealed that the 5 HTT-LPR gene is definitely linked to having a more anxious, neurotic personality. And, they also assert that the DRD4 receptor was associated with having a more outgoing personality. The scientists state that it has been established that anxious, neurotic personalities and outgoing personalities are linked to substance misuse such as smoking. Therefore, they argue that genes must be responsible for smoking. The results of the Cancer Research UK's GP research group in Oxford on genes and behavior are dubious for a variety of reasons. Even by the scientists' own admission, only two genes were found to be "robustly related" to behavior and the environment such as a childhood experience or diet will also have a large influence on how genes are expressed (Bhattacharya, 2003). Further, it's not clear how the influence of environmental factors on the two personality types were taken...

Combining data from 46 separate studies is also questionable.
Although the Cancer Research UK's GP study has shown some interesting findings linking serotonin and dopamine genes with tobacco addiction, research is a long way from being proved. Perhaps as the UK scientists suggest, there may eventually be a way to identify people with genes that lead to addiction and develop specific stop smoking programs and messages for them. Even so, it appears that Jennifer would ultimately still have to rely on her own will power to quit.

Bibliography

Azar, B. (2002, September 8). Searching for genes that explain our personalities. Monitor on Psychology. Retrieved November 27, 2006 from Web site: http://www.apa.org/monitor/sep02/genes.html

Bhattacharya, S. (2003, June 17) Genes linked to high-risk personalities. Molecular Psychiatry Vol 8, p. 471. Retrieved November 27, 2006 from Web site: http://www.newscientist.com/article.ns?id=dn3841