Childhood poverty, adult stress, and demographics, including sex, age, and ethnicity, leave a mark on individuals' genes, which may contribute to their immune response.

A previous study from the University of Gothenburg, Sweden suggested that genes linked to the immune system can have an influence on healthy individuals' personality traits, chance of developing mental illness, and risk of suicidal behavior.

The current finding, published in Proceedings of the National Academy of Sciences, came from a University of British Columbia and Centre for Molecular Medicine and Therapeutics (CMMT) study, which set out to examine how our experiences before birth and in the years that follow can influence the way our lives turns out.

The scientists explored changes in gene expression, a study called epigenetics, by closely observing a process called DNA methylation. In this process, a chemical molecule is added to DNA that turns genes on or off or sets them at a place in between.

Previous research has indicated that every experience we encounter throughout life impacts on the formation of DNA methylation patterns.

According to the experts, there was a correlation between childhood poverty and the marks or methylation patterns left on genes, but not with socioeconomic status.

"We found biological residue of early life poverty," explained Michael Kobor, an associate professor of medical genetics at UBC, whose CMMT lab at the Child & Family Research Institute (CFRI) led the research. "This was based on clear evidence that environmental influences correlate with epigenetic patterns."

An association was seen in the variations in DNA methylation with the amount of stress that adults produce.

It is not clear whether the marks contribute to the amount of stress hormones released, Kobor explained, or whether heightened stress levels as an adult leave marks on DNA.

Kobor, also a Mowafaghian Scholar at the Human Early Learning Partnership (HELP), and his team demonstrated that future immune responses could be predicted by methylation patterns, meaning that what happens to us early in life could influence our response to illness when we are older.

Written by Sarah Glynn