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Nov 4, 2012 by KAREN FOSTER
Why Do Children Have To Experience Such Adversity At a Young Age?

How do we overcome the emotional distress we feel for the disabilities, pain and suffering of children and infants? It is time to embrace growing evidence that it is the interaction between biology and environment in early life that influences human development. Despite what we perceive as negative experiences in life, especially as children, adversity shapes human beings paving our life's path and embedding in our biology.

According to a series of studies recently published in a special edition of the Proceedings of the National Academy of Sciences (PNAS), It is time to put the nature versus nurture debate to rest.

Parents and society share a stake in the successful development of children. A vital quality of resilient communities is that they foster the development of their children into competent adults and productive citizens. However, many children grow up in hazardous environments, burdened by poverty, violence, troubled parents, divorce, and discrimination.

For many years, researchers studied the problems of children whose lives were threatened by the accumulation of risk factors. Then, about 25 years ago, a group of pioneering investigators realized that some children managed to succeed in spite of adversity and disadvantage, and the systematic study of resilience was born. Resilience research was aimed at understanding how some children grow up competent in spite of many risk factors in their lives.

"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).

Sokolowski, who is a University Professor in the Department of Ecology & Evolutionary Biology (EEB), the inaugural academic director of U of T's Fraser Mustard Institute for Human Development and co-director of the Experience-based Brain and Biological Development Program (EBBD) at the Canadian Institute for Advanced Research (CIFAR) says that relatively little is known about the gene-environment interplay that underlies the impact of early life adversity on adult health and behaviour.

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. Fruit flies are especially useful for genetic studies because they share a surprising number of qualities with humans, are inexpensive to care for and reproduce rapidly, allowing for several generations to be studied in just a few months.

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.

"`Even though a whole lot of traits--including IQ--have been shown to be highly heritable, much of the effect of genes may come from the way genes seek out good environments,'' said study lead author William T. Dickens of the Brookings Institution in Washington, DC.

Seemingly small environmental triggers play a large--if changing--role in influencing an individual's IQ. In what the researchers suggest is a snowball effect, a person who is perhaps only slightly more genetically "gifted'' than average may have easier access to social and work situations that involve higher-than-average degrees of intellectual stimulation.

"The foraging gene makes an enzyme called PKG, which is found in the fly as well as in most other organisms, including humans. When faced with a nutritionally adverse environment while growing up, the levels of the enzyme dropped in flies,"says Sokolowski. "This told us that the foraging gene listens to its environment."Transgenic manipulations of PKG levels altered darting exploration in well fed but not nutritionally deprived flies.

The research team included James Burns, a CIFAR junior fellow in Sokolowski's lab, U of T EEB professor Locke Rowe and EEB post-doctoral fellow Nicolas Svetec, as well as colleagues from the University of British Columbia and the Université Paris-Sud. 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 Science.

The papers in the volume are authored largely by CIFAR researchers, and comprise a multidisciplinary collection of research into fields from molecular genetics, evolutionary biology and neuroscience, to social and behavioural science, epidemiology and social policy -- as well as the emerging field of epigenetics, which investigates deviations in a gene's ability to produce its products (e.g. RNA, protein) caused by mechanisms other than changes in an organism's underlying DNA sequence.

The collection of papers in the volume sets out an emerging new field of the developmental science of childhood adversity, and changes conventional understanding of the early years of human life. Parenting skills may also come into play when understanding this phenomenon.

"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.

Children who succeeded in the face of adversity have more internal and external resources, particularly in the form of good thinking skills and effective parenting. Adversity does not seem to derail development unless key adaptive resources were weak, or impaired by the adversity itself.

Resilient children have a great deal in common with other competent children who have no more than the normative level of stress in their lives. They are good problem solvers, able to learn and pay attention. They are close to adults in their lives who provided warmth, age-appropriate structure, and high expectations for them.

"Developmental neuroscience is extraordinarily intricate and complex, and so by approaching this question from multiple angles we're able to reveal a convergence on a number of themes and set a clearer direction for future research,” said Sokolowski

Karen Foster is a holistic nutritionist, avid blogger, with five kids and an active lifestyle that keeps her in pursuit of the healthiest path towards a life of balance.

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