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The Common Basis of Addictive Behaviors: Over-Eating and Drug Abuse

I will never forget the first time my naive idealization of the Punnett square as the sole descriptor of human genetics was shattered. I was 15 y ears old attending my first conference on genetics when a Harvard-educated geneticist, Dr. Sam Rhine, gave his analogy of genetics as a world of "three boxes." The first two, labeled cytogenetics and monogenetics, contained all the diseases that my freshman-year biology course explained so easily with the story of Mendel and his plants, simple gene dominance and recessiveness, and nondisjunction of chromosomes. Such diseases included Down syndrome, Klinefelter syndrome, Cystic Fibrosis, and Muscular Dystrophy. I smiled with delight as I recalled the karyotypes and Punnett squares I had so often seen for these diseases. It was then that Dr. Rhine pointed out how rare such diseases were. “So why not study the most common human diseases, like Type 2 Diabetes, Hypertension, ADD, or Bipolar Disorder?” he asked. This is when he presented the third box, which he labeled “multifactorial.” It was then that I realized so many common illnesses afflicting the modern world were much more complex in origin than I could have ever imagined.

This brings me to an article I read recently in Nature Magazine’s web focus on addiction. This study ultimately points out that there are common biological mechanisms relating drug addiction and obesity; just as genetic factors play a role in vulnerability to drug addiction, they do so as well in vulnerability to obesity. Just as environmental cues that predict the delivery of drugs increase dopamine transmission in certain brain areas, they do so as well when predicting the delivery of palatable food, which can help explain the often addictive nature of delicious food – something we have all experienced at some point. This study remains constant with the theme that genetics are increasingly complex and not easily explained with a simple Punnett square. Our genes make some of us more likely to over eat, abuse drugs, etc., a fact that can serve as a reminder as to why being aware of one’s own addictive tendencies can be important in preventing over-eating and other harmful and excessive behaviors.

Lindsey Rogers, Summer Research Intern


Kenny, P. J. (2011, NOVEMBER). Common cellular and molecular mechanisms in obesity and drug addiction.Nature, 12, 638-651. Retrieved from http://www.nature.com/nrn/journal/v12/n11/pdf/nrn3105.pdf

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