Information about GENES

Researchers are still not sure what influence genes have on human health, behavior, and personality.  In fact, we are trying to help figure this out with our research study.  What we do know is that (1) the effect of any one gene is very, very small, and (2) the effects are “probabilistic.”  “Probabilistic” means that a certain gene may be associated with a behavior on average in a large group of people, but this association does not necessarily apply to any one individual person.  So, we won’t be able to “diagnose” you with anything on the basis of your genetic information, but we may be able to detect average genetic differences between groups of people.  For example, a group of people that drink alcohol very often may be different, on average, from a group of people who never drink.

You have two copies of every gene – one from your mother and one from your father.  Each of the genes that we will look at comes in two or more versions – a version that is more common in the U.S. population and a version that is less common.  So, what we measure is how many copies of the rare version do you have – 0 copies (neither your mother nor your father gave you the rare version), 1 copy, or 2 copies (both your mother and your father gave you the rare version).

We will be focusing on 5 genes. All of the genes are related to neurotransmitters, chemicals that your brain cells release in order to communicate with other brain cells. These genes are thought to affect how strong the neurotransmitter signal is – like turning up the volume on your phone.

  • GABRA2 = This gene codes for part of the receptor for GABA.  GABA is the brain’s “inhibitory” neurotransmitter, which means that it generally slows things down.  Many of the effects of alcohol – making you feel sleepy or relaxed – are due to GABA.
  • DRD4 = This gene codes for part of a receptor for dopamine.  Dopamine is involved in feeling pleasure.  Anything that makes you feel good – food, sex, drugs – involves dopamine pathways in your brain.
  • OPRM1 = This gene codes for part of an opioid receptor.  Opioids are involved in dulling the body’s sense of pain.  These receptors respond to opiate drugs – like morphine or heroin – and also to the body’s own natural opioids, known as endorphins.  If you’ve ever gotten a runner’s high, you’ve experienced your opioid receptors at work.
  • CHRM2 = This gene codes for part of an acetylcholine receptor.  Previous research has found that people with a certain version of this gene are more likely to drink heavily, use drugs, and have ADHD symptoms.
  • 5HTTLPR = This gene affects the serotonin receptor. Serotonin is involved in mood, appetite, and sleep.  Previous research has found that people with a certain version of this gene may feel the effects of alcohol more strongly.

You may have seen TV shows or movies where lawyers or cops take a sample of someone’s DNA. This study is not like TV! We will not be doing anything “forensic” with your DNA.  We won’t be able to match you with any database, or tell whether you committed a crime, or let you know who you are related to.  We won’t share your genetic information with anyone.

When you give a saliva sample, you’ll spit into a tube.  Your spit contains tiny cells from the inside of your cheeks, and these cells have your DNA. As soon as you close the lid on the tube, the lid releases chemicals that stabilize the DNA.  After we get your sample from you, we will send it to a lab that will isolate the DNA and “genotype” it – measure which versions of these 5 genes your saliva contains.