Are you the way you are because of the genes you inherited or the experiences you have gone through? Are we born with a clean slate, a Tabula rasa as it were, and therefore who we become is mainly informed by our environment and the way we are reared; or are we born already wired and equipped with traits that will shape who we are as individuals?
Nature vs. nurture is an Ancient Greek concept. Nature has to do with an individual’s inherited traits; you are pre-wired at birth with certain attributes that will determine who you will become. Whereas nature has to do with how external factors affect the development of an individual. For centuries, the debate on human development tended to focus on favoring one side or the other. Nevertheless, with the advancement of science and our ability to delve deeper into our make-up on a molecular level, it has become quite clear that both are involved in how we turn out.
Until recently, it was thought that genes are simply hereditary and static; you were born with them and your genetic traits were inherently unaffected by your environment. However, recent research in “epigenetics”—a field of study that delves into these questions—is changing that. Dr. David Moore, the author of The Developing Genome, states “[f]or the longest time, the nature-nurture debate has been cast as a kind of contest between genes and experiences.... What epigenetics is making clear is that is a faulty way to think about the situation, because it is not true that genes do things independently of their contexts. Instead, genes do what they do because of the contexts that they are in. Nature and nurture are always working together to produce all of our traits”.
In epigenetics, “epi” means above or on top of, which is an indicator that there is something else on the “gene”; it is an external modifier to the gene that can switch it on or off. The DNA sequence remains the same; how it is read by other cells is what changes; epigenetic changes can interfere or boost with the transcription of specific genes. This is through the attachment of chemical tags to the DNA or protein wrapped around the DNA. These chemical tags are the epigenomes, which can stop some genes from being read and in a sense switching them off, or allows some genes to be easily accessible and therefore easier to produce proteins using their codes. The creation of epigenomes is affected by many factors, including diet, medication, exercise, exposure to pollutants, or even social situations.
It was believed that epigenetic changes were not passed on from parent to child, but it has been proven that it is possible. In a study done on rats, before they were subjected to an electric shock, the rats were exposed to the odor of cherries; after a few times, the rats became stressed and fearful when they could smell the cherry odor. The offspring of those rats showed the same fear of the cherry odor even though they were not subjected to the electric shock. A change on the molecular level happened in the original rats due to their environment, this change was epigenetic in nature, and it was passed on to their offspring.
While this was a study done on rats, the implications point to the idea that epigenetic changes cannot only occur because of the environment you are in, but can also be passed on from one generation to the next. At the same time, epigenetic changes are not always permanent. In this way while genomes remain unchanged, epigenomes can change the way they are expressed, and mediate the relationship between genes and the environment. Nature and nurture, viewed from this angle, are always interrelated and at play.
While we do inherit our genes, which is beyond our control, it is clear that the epigenomes that form are affected by the way we lead our life. It is a new avenue of exploration with untapped potential; the growing field is another step science has taken in order to gain further understanding into the enigma that is human development.
References
behavioralscientist.org
whatisepigenetics.com