DNA has been hyped up in the media as of late, but there is still a great deal of misunderstanding about what role it plays in human development. There is no doubt that genetics provide a rough sketch for who we might become. Our genes can predisposition us towards certain personality traits, certain strengths and weaknesses, and of course, certain physical traits. Yet DNA hardly transcribes our essence into stone. It is biologically impossible for a gene to operate independently of its environment. (Plomin & Crabbe, 2000) All genes, by design, are built to be regulated by signals/conditions in their surroundings. There are around 25,000 genes in the human genome, containing operating instructions that guide all of the approximately 50 trillion cells in our body. But here’s where the process becomes much more complicated: Each of those 50 trillion cells have a multitude of receptors that receive information, process it, and initiate an electrochemical process that alters our very genetic code. (Giancotti & Ruoslahti, 1999) The human body is very much like an ecosystem: you can identify that there are fish and frogs and snakes and water and trees and other little critters, but that hardly provides a full explanation as to how they’re all going to interact together. As such, our understanding of the genetic code hasn’t done much of anything to increase our knowledge of something so complex as human behavior. (Attwood, 2000) It plays too small of a role in the overall equation.
Gene expression is dependent upon a variety of other factors, such as:
- Chemical environments in the womb.
- The diet, lifestyle, and general mood of the mother.
- Those other nomes: Epigenome (methyl tags that attach to DNA and turn genes on or off and alter their expression), Meta bolome, Microbiome (bacterial symbiotes which outnumber your actual human cells 10 to 1), Physiome, Exposome (our history of chemical exposures), Proteome, and transcriptomes, just to name a few – all of which influence genetic expression.
- RNA (Like DNA, only chemical based rather than protein based) which influences DNA expression.
- Environmental factors, such as the air we breathe and the food we eat, as well as the climate.
- Our emotional surroundings and how much stress we experience.
- Social factors.
Certain genes can be “turned on” or “turned off” based on what a person encounters in the environment, and heritable changes in DNA can occur without any actual changes in the DNA sequence. (Wolffe & Matzke, 1999) For example, a predisposition towards obesity can be changed simply by maintaining an active and healthy lifestyle, which will “turn off” any genes related to obesity. What’s more, a mother who gets herself into shape and maintains an active lifestyle will pass on these improved genes to her offspring.
In another example, scientists have linked a variant of a gene known as DRD2, which regulates receptors for dopamine, to a fussy temperament in babies. However, “exposure over time to sensitive parenting seems to counteract the effects” of the higher-risk variant of the gene, says Cathi Propper, lead author of the study. By 12 months of age, infants with this variant who were consistently attended to responded to stress just as effectively as did babies with other versions of the gene. (Anthes, 2009) This study provides a good example of the nature-nurture interplay at work, and also illustrates how parental responses can overcome any biological quirks related to adversity.
A large factor in gene expression is epigenetics, which are being written every day. The process of epigenetics is basically like scribbling notes or whiting out paragraphs in a book while editing others. Dictated by environmental influences, epigenetic expression changes the structure of DNA. Nobel prize winning scientist Eric Kandell notes that our social environments, emotions, and belief systems all promote physiological responses powerful enough to alter gene expression. (Kandell, 1998) So although genetics form the building blocks for who we are, it’s becoming clear that the tables are tilted towards environmental factors playing a much larger role in who we become. (Mann, 1994) With that in mind, let’s take a look at some of the ways biological factors can influence a child’s response to adversity:
On dandelion children and orchard children: genetic variants in resiliency
Different children also seem to have innate levels of resilience, whereas others more quickly crumble in poor environments. Psychologists often refer to these children as “orchid children” (those who are highly sensitive and susceptible) and “dandelion children,” who seem to thrive even in harsh environments. Wray Herbert, a writer with the Association for Psychological Science, explains that “dandelion children seem to have the capacity to survive – even thrive – in whatever circumstances they encounter. They are psychologically resilient. Orchid children, in contrast, are highly sensitive to their environment, especially to the quality of parenting they receive.”
The interesting thing is that while orchid children tend to quickly wither in poor environments, they tend to excel in healthy ones. “If neglected, orchid children promptly wither – but if they are nurtured, they not only survive but flourish. …The genetic variant that combined with lousy parenting to produce the worst aggression and delinquency also combined with the most attentive parenting to produce the best teenage outcomes. Put another way, the kids who run the highest risk of developing bad behavior in bad homes were least likely to struggle when living in healthy, nurturing homes.” (Herbert, 2011) As researchers Thomas Boyce and Bruce J. Ellis eloquently put it, in a positive environment, an orchid child becomes “a flower of unusual delicacy and beauty.” (Boyce & Ellis, 2005)
This gives you an idea about how different children react to different environments, and how nature versus nurture are doing the tango with each other throughout childhood to shape who kids become. The good news in all this is that good environments overcome anything, and every child can thrive in positive settings.