The question of nature or nurture, i.e. whether biology or psychology, is more influential in determining human qualities has been around since the time of Freud. The argument for nature comes from the similarities of separated twins. Further evidence is known by all parents with more than one child. Inevitably, they will be different despite the similar parenting. On the nurture side, there are studies that show parental bonding establishes happy, stable children. Often the argument ends with the lament that it does not matter. In a traditional family, parents provide both nature and nurture.
The question suggests that nature and nurture are distinct from one another. The purpose of this blog is to argue they are not. That nature influences nurture seems obvious. If parents are genetically disposed to patience, tolerance, gentleness, they will be more nurturing. If a child is a monster, hell bent on creating chaos, parents’ ability to be caring will be strained.
What is amazing to me is that recent studies show that nurture can affect nature. A relatively new area of study called epigenetics is providing insights into human inheritance. Since the 1970s, researchers have known that the tightly wound spools of DNA inside each cell’s nucleus require something extra to tell them which genes to activate.1 One of the ‘extra somethings’ is called the methyl group. If the DNA is a recipe book, the genes are the chapters, and the methyl group is a set of attached post-it notes to indicate which chapters contain the proteins to be created for the cell.
Diet, environment, exposure to certain chemicals can add or take away the post-it notes, also described as switches that can turn genes on or off. Amazingly, change in the gene selection can be passed on to offspring.What fascinates me is that I believe this explains the puzzling adaptability or rapid evolution of species. Mutation seems too random and slow to account for short term changes, at least to my satisfaction. There are reports of bird populations whose color lightened after posts on which they customarily roosted were painted white, then darkened again as the posts weathered. Matching the posts’ color makes smaller birds more difficult to spot by larger predator birds. Salt-water fish dumped into fresh water lakes by a tsunami have adapted to the new salinity. The salt-water dumped with them meant the new water was not too different from sea water, but rain fed the lakes diluting the amount of salt over time. Again, the adaptations were passed on to their descendents.
Most recently discovered is that nurture or lack thereof can also switch genes on or off, with changes passed to offspring. Imagine that an abused or adored grandmother can help define who you are. At the genetic level, you carry your ancestors’ life experiences.
The good news is that you can actually change your gene structure with a healthy diet, environment, and your children’s by nurturing them. It is possible that a child who inherits genes which make them anxious and unstable can through extra caring undergo genetic change. This has a profound impact on potential new treatments for healing the brain.
- Adapted from http://discovermagazine.com/2013/may/13-grandmas-experiences-leave-epigenetic-mark-on-your-genes