DNA is the hereditary [1] blueprint making up [2] all people and all organisms. We get genetic information from both of our parents, and DNA itself can’t be changed after birth. That doesn’t mean, though, that who we are is set in stone after birth. Indeed, the question of nature or nurture has been answered by epigenetics—the truth (which aligns [3] well with intuition [4]) is that it’s a combination of both.
Epigenetics, most broadly, is the study of how the environment and one’s behavior can influence the way that genes work. While DNA itself can’t be changed, cells can control the activity of genes by turning them on or off. In practice, this means that trauma and habits from one life can be passed down through generations. The traumas and habits themselves don’t cause genetic changes but rather epigenetic changes that influence how genes are expressed.
A study of children born during the Chinese Famine* revealed that they had specific epigenetic changes in the IGF2 gene, which was later associated with higher cholesterol in late adulthood. Not all epigenetic changes are bad, though—choosing to exercise today can trigger positive epigenetic changes in genes involved in metabolism and stress resistance. Epigenetics, then, is a reminder that who we are is what we make of ourselves; despite having a blueprint, we can still become anything we want to be.
* Editor’s note: The Chinese Famine, which took place in the year 1959 was one of the deadliest famines in human history, with upwards of fifty-five million deaths. It resulted from a combination of natural disasters and policy mistakes on the part of the People’s Republic of China.