Early life development impacted by adversity

Toronto, ON – It is the interaction between biology and environment in early life that influences human development, according to a series of studies recently published in a special edition of the Proceedings of the National Academy of Sciences (PNAS).

This is a new wrinkle in the ageless debate of nature versus nurture. “Biologists used to think that our differences are pre-programmed in our genes, while psychologists argued that babies are born with a blank slate and their experience writes on it to shape them into the adults they become. Instead, the important question to be asking is, ‘How is our experience in early life getting embedded in our biology?’” says University of Toronto behavioural geneticist Marla Sokolowski. She is co-editor of the PNAS special edition titled “Biological Embedding of Early Social Adversity: From Fruit Flies to Kindergarteners” along with professors Tom Boyce (University of British Columbia) and Gene Robinson (University of Illinois).

In one of the studies in the series, Sokolowski and her colleagues found that chronic food deprivation and lack of adequate nutrition in the early life of the fruit fly Drosophila melanogaster had significant impact on adult behaviour and quality of life.

The researchers examined two types of fruit flies with variants in the foraging gene (for) known as rovers and sitters because of their different behaviours in the presence of food.

When well fed as larvae, rover adults exhibit darting exploration into open areas as they move about in search of food, while sitters show little of this behaviour. When nutritionally deprived as larvae, both rover and sitter adults exhibit darting exploration. Further, the sitters that faced nutritional adversity in early life displayed a reduction in their ability to reproduce. Rovers exhibited no effect on their reproductive fitness.

“This is the first volume of collected research to provide a substantial and comprehensive picture of the interaction between experience and biology in the early years,” says Sokolowski.

The findings are reported in the paper “Chronic food deprivation in early life affects adult exploratory and fitness traits”, in the October 16, 2012 issue of the Proceedings of the National Academy of Sciences.