This blog is a place where I will translate interesting findings in biomedical and basic science research from scientific jargon to plain old English. The bottom line: You don't need a PhD to understand science!

Wednesday, August 26, 2009

Does our DNA make decisions for us?

In this week’s Proceedings from the National Academy of Science, Christina S. Barr and colleagues report that a mutation in the CRH gene is associated with increased stress-induced alcohol consumption in primates. What are the implications of this study and those like it? What does it mean if a DNA mutation can shape behaviors that affect our society?

First, let’s catch up on the basics. The CRH gene is the piece of DNA that encodes instructions to make corticotropin-releasing factor (CRF), a piece of cellular machinery required by our bodies for stress adaptation. Too much CRF activity can lead to increased anxiety or depression-like symptoms.

Barr’s research involves a mutation in a region of the DNA directly before the CRH gene, called the CRH promoter. In a sense, a gene’s promoter is like password protection for the gene. If the cell doesn’t use the proper combination of factors to satisfy the password, the instructions in the gene cannot be accessed. Other times, a faulty promoter will allow access to the gene too often. In the current study, the mutation in the promoter for CRH causes the cell to make too much CRF.

To determine if the CRH mutation affected stress-related behavior, Barr exposed young macaques to peer rearing (as opposed to mother rearing), an environment that is known to induce stress in these young animals. Next, Barr’s team measured the differences in alcohol consumption between normal macaques and those carrying the CRH mutation. After early stress exposure, the macaques with the CRH mutation consumed significantly more alcohol than the controls with a normal CRH gene.

Stop and think about this result for a moment. What does it mean if a gene mutation significantly affects a quantifiable behavior? To what extent does our genetic make-up contribute to the thousands of decisions every individual makes each day. The outcome of most decisions is benign; what one eats for breakfast or wears to work most likely won’t evoke a second thought. Other decisions, however, can have large impacts on society. The choice to consume excessive amounts of alcohol, engage in violent behavior, or disregard accepted social contracts can land a person in jail, if not worse.

Science progresses at an exponential pace. It is not unlikely that ten to twenty years from now, many more genes will be associated with specific behaviors. There will be a time when a jury will need to decide if a crime was committed with criminal intent or if the accused was at his DNA’s will. To properly handle these future scenarios, we as a society need to develop a basic understanding of cellular biology and learn how to assess the possible implications when something has gone amiss at the genetic level.

One hundred years ago, demons and devils were blamed for unacceptable behavior. One hundred years from now, who will be on trial: the perpetrator or his DNA? These are not questions for a science fiction novel or the next blockbuster film. These are relevant issues that warrant discussion based on educated reason.

Reference: Christina S. Barr et al. “Functional CRH variation increases stress-induced alcohol consumption in primates.” PNAS August 25, 2009. DOI: 10.1073/pnas.0902863106


  1. Excellent topic, it's so critical to debate the ethics of "criminal profiling" before people run rampant with their own version of justice!

  2. As they say in the military: you don't promote the person, you promote their record. Meaning that the potential promotees don't meet the promotion board, their paperwork does. I can see the same analogy to this legal debate. A person doesn't get put on trial, their record or in this case, their genes do. To the extent that the legal system deals with judging people based on their actions and proof of those actions, it will be the standard of "proof" that comes into question. It's a scary proposition and needs to be discussed amongst the great critical thinkers of our time. Whenever gene-typing or gene profiling becomes a larger issue, it will also need to be communicated to society and to our legal representatives. We don't need this to turn into Minority Report, what with their pre-crime division and all...

  3. Yes! That's exactly what I'm talking about. Great analogy to Minority Report.

  4. It will be interesting in later to see if one can overcome the blueprint they were forcibly handed. Something that must be addressed in the future is understanding the complex relationship between individual mutations or abnormalities within one's genetic "profile" and the direct or indirect alterations in behavior resulting from each. As science delves deeper into functionality of said gene products, larger web-like modeling of interactive networks may show that some alterations are benign, whereas others may have dire consequences. Currently, certain areas of scientific modeling are attempting to simplify these into more tangible interpretations. Although in their infancy in many cases, this may help clarify potential causes of uncharacteristic behavior.

    But then that may cause issues with accountability, if you can claim that it was your "genes fault", should you be responsible?