Genes Influence Behavior My Friend

¶ … Genes Influence Behavior

My friend Jennifer smokes about a pack of cigarettes a day. Despite constant nagging from her friends and her family and her own stated desire to quit, she is unable to break her smoking addiction. She is very concerned that smoking causes serious health consequences and even death. In the past, she has quit for short periods of time. But, then she encounters some stress in her life that she claims causes her to start smoking again. Jennifer states that cigarettes help calm her nerves. Is Jennifer's smoking habit attributable to her own lack of will power or is there something else going on? Some scientists now believe that people are genetically predisposed to their habits such as smoking. However, the jury is still out on whether or not this can actually be proved.

The goal of research on genes and behavior is to discover genes that affect brain functions that in turn affect how people interact with their environments (Azar, 2002). But, the research is very complex because many genes are responsible for various aspects of people's temperament. According to Azar (2002), genes appear to interact with each other in complicated ways that influence several traits at once -- and then likely only in very subtle ways, with any one gene likely accounting for only one or two percent of the variance in a trait. This means that hundreds of genes potentially influence each of our personality traits. However, there are only two candidate genes related to behavior that scientists can understand with any degree of confidence (Azar, 2002). The first gene is a dopamine receptor called DRD4 that may have a link to novelty seeking behavior. The second is a serotonin transporter gene called 5-HTTLPR that may be linked to neuroticism and additional anxiety-related traits such as harm avoidance.

Despite the difficulties of linking genes to behavior, a scientists at Cancer Research UK's GP research group in Oxford claim they have done so (Bhattacharya, 2003). 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 into consideration. Combining data from 46 separate studies is also questionable.