Key points
- Trauma affects generations but is not directly encoded in genes
- Phenotypic plasticity causes different outcomes from same genes
- Epigenetics regulates gene activity without changing DNA code
- Environment, culture, and caregiving shape trauma transmission effects
ISLAMABAD: As conflict continues in Gaza and Ukraine, concerns grow about how trauma might affect future generations in these regions.
Recently, interest in transgenerational trauma has surged. For instance, National Geographic asked whether trauma is carried in our genes. While an intriguing question, it is somewhat misleading: trauma can influence generations, but its effects are not directly coded in DNA.
The key concept here is phenotypic plasticity — the ability of organisms to produce different outcomes from the same genes depending on their environment. These outcomes, or phenotypes, can include stress sensitivity and physical traits.
Altering genetic code
One mechanism for this is epigenetics: small chemical changes to DNA that regulate gene activity without altering the genetic code itself. Think of it as a director’s notes guiding which parts of a script to emphasise. However, epigenetics is only one expression of plasticity.
To understand trauma transmission across generations, we must look beyond genes to the environments shaping them. Human development is influenced by lived experiences — caregiving, community, safety, and belonging — which interact to create lasting but flexible effects.
Phenotypic plasticity is common in nature. For example, genetically identical honeybee larvae become queens or workers depending on diet. Similarly, fish exposed early to predators develop altered stress responses and body shapes. These are environmental effects, not genetic changes.
Early life experiences
In humans, early life experiences shape development too. Children raised in unsafe conditions may become highly vigilant, a useful trait in danger, but potentially leading to anxiety in safer environments—a phenomenon known as environmental mismatch.
Plasticity complicates predictions of trauma’s effects across generations. Research in fruit flies showed how diet in one generation influenced health and lifespan in descendants, with outcomes varying between generations.
Epigenetic changes linked to early adversity are not permanent scars. They can shift with changes in environment, such as family stability or social support. Trauma may also be passed on through hormones, immune function, or conditions in the womb, all influencing brain development and stress responses.
Cultural connection
Cultural connection is crucial. In New Zealand, Māori-led initiatives focusing on land, language, and ancestry help heal trauma from colonisation. Similarly, Holocaust survivors and their descendants find strength in shared cultural identity.
Psychological interventions like trauma-informed parenting can improve outcomes in future generations. These supports influence biology by reducing stress hormones and bolstering immune function.
Ultimately, inherited vulnerability is not a fixed wound encoded in DNA, but a malleable response shaped by context. Thanks to plasticity, our biology interacts continually with our environment, meaning that changing the context can change the outcome.
