Is nurture the most important factor that determines our personal character, or nature? Until now, we have settled for a mixture of both. In his new book, Blueprint: How DNA Makes Us Who We Are, Professor Plomin writes of DNA as “the major, systematic force”. The key to our personality appears to lie in the genetic information we inherit from our parents, which was traditionally more linked to environmental effects such as our upbringing. While environmental effects are still considered important, they are an unsystematic and unstable force and environmental effects may even be genetically influenced as well, according to Plomin.
In the ‘70s, much of our uniqueness as a person was ascribed to environmental effects. However, since the acquired capability to map the human genome (2003) and to spot the crucial genetic differences that make each one of us unique have reframed that debate, this view has changed drastically. Humans share 99% of their DNA, and the 1% that differs is responsible for our uniqueness. This 1% consists of thousands of DNA differences that have tiny effects: this makes the genetic influence probabilistic, rather than deterministic, according to Plomin. Plomin puts thousands of DNA differences together to predict differences in traits. For instance, he could predict 10% of interpersonal divergence in weight and depression.
There is anxiety about the ownership and exploitation of genetic data. Some insights into our genes even risk stimulating eugenics. Indeed, Plomin believes his research results will be big business and prone to commercial interests, and he has already turned down funding from commercial parties, such as Tinder. As we are entering the age of genetic information, reflecting on the way we deal with these new insights will become more urgent and this will demand a vision of how these insights could be used as a source for good, such as a shift from curing sickness to staying healthy.