Bill Sullivan's new book, "Please To Meet Me," explores the way genes and environment shape our lives. Sullivan, a professor at the Indiana University School of Medicine, talked with Side Effects' Steph Whiteside about the book and what he found out while researching it.
Steph Whiteside: Why did you decide to write a book on this topic?
Bill Sullivan: I wanted to understand why some people overeat, why some people are violent, why some are so smart, and why some seem happy all the time. Personality and actions are under the influence of hidden forces, genes, epigenetics, microbes, and our subconscious, many of which we have little to no control over.
Whiteside: You say it's not just our genes that influence who we are, it's also environment. What is epigenetics?
Sullivan: Everyone's born with their complements of chromosomes and the genes that they're going to be born with. But what is happening while the baby is in the womb is that those genes are being tweaked at an epigenetic level. And this is largely dictated by the environment that mom finds herself in.
Whiteside: You also talk about the facts of environment being passed down.
Sullivan: There was a hunger, famine in World War II that took place when the Germans blockaded the Netherlands. Now, mothers who were starved during their pregnancy had children who grew up with higher rates of obesity and diabetes. Their genome was epigenetically programmed to survive in a famine by maximizing calorie extraction from food. But there's no famine today. And the tweaks that were made to their genome are causing obesity.
Whiteside: What can this kind of research tell us about violent behavior?
Sullivan: There is good evidence that mutations in a gene called MAOA, which manages brain chemistry, and other genes have also been linked to a higher risk of violent behavior. Epigenetics is another part. Poor socio-economic conditions or child abuse alters the expression of genes that control the ability to manage stress. So these biological explanations are not "get out of jail free" cards, but they are important reminders that, at least in some cases, the perpetrator may not be in full control of his or her actions. Criminal behavior has a biological explanation, and if we figure it out, we might be able to do something about it.
Whiteside: How can we as a society use this research?
Sullivan: The trauma seems to echo through multiple generations and unfortunately, and we're seeing this played out in situations around the world today. And we are setting up potentially multiple generations, through epigenetics, to be predisposed to very undesirable traits and behaviors because we're not taking care of children.
This story was produced by Side Effects Public Media, a news collaborative covering public health.