The Studies Linking DNA and Behavior
by David Berry
The Studies Linking DNA and Behavior
We don’t know all of the genes that are in human DNA. The Human Genome project, among others, is reading the DNA of a single human being for the first time. When the project is complete they won’t know what the DNA does, but they will have documented the sequence. While human DNA is primarily the same in all of us, there are many tens of thousands of slight variations that determine our individual characteristics. Until we know what those variations are and what role the environment plays in how those characteristics develop, we cannot know for sure how much DNA influences behavior.
Twins Based Studies
The studies that offer evidence of DNA being a strong influence on behavior are rather simple. During the depression the extreme hardship of the times promoted the practice of giving one twin up for adoption. There are about a thousand identical twins that have grown up with the same DNA in completely separate environments and have been extensively interviewed to find out what characteristics they have in common. There are some twins that have an amazing amount of coincidental similarities and other twins that have virtually nothing in common. Within that range, there are many behaviors that are unusually common. The conclusions of the twins’ studies are that between 40% and 60% of our behavior, health and personality are a result of genetic influences.
The characteristics measured were extensive and included a wide range of topics like weather or not they had diseases, smoked, drank, were smart, had a good job history, sexual preferences, were outgrowing, liked particular foods, had hobbies and hundreds of other specific characteristics. 40% in common might not seem that much, but we are talking about two people that are raised in different parts of the country in completely different situations if we are all born basically with the same capacity.
DNA Based Studies
There are other studies that actually identify particular genes in a group of people with particular characteristics. Some well-publicized studies researched alcoholism, sexual preference, intelligence and criminal behavior. Indeed, particular types of genes were found in many people with particular behaviors, but the same gene was also found in people that did not exhibit the same behavior. Again, it was determined that 40% to 60% of a persons behavior was based on a genetic predisposition.
What these studies do not say are which people with what genes will behave one way or the other. Environment has such a tremendous role in our development of morals, ethics and interest that genes are no guarantee of behavior. Similarly, diseases like cancer, Alzheimer’s, alcoholism or heart disease are related to genes, but the genes are dependent on environmental factors at least to some degree for the potential to become a reality. Until more is known we must assume that free will exists and that we are, to some significant degree, masters of our own destiny.
Other New Humanity Times
Articles About Genes and Free Will
DNA and Free Will
Genetics and the envoronment may have more to do with what we think, our choices and what we do than our free will
Is Genetic Modification Natural?
Is it unnatural to be changing the genes that are the program of life?
Understanding Complex Systems
Individual genes are interrelated in a matrix. The theory behind complex systems is key to understand how gentics and evolution work
Off-Site Links About How Genes Influence Behavior
To read and listen to NPR radio’s excellent series, The DNA Files, click here.
To listen to Is Our Fate in Our Genes?, one of the NPR programs, click here.
For a more detailed look at the role of gentics in behavior, click here.
This paper was written by a professor at the Center for Developmental and Health Genetics, Pennyslvania State University
