Previous studies have provided a strong basis of support for hypothesis that individuals with particular genotypes are predestined to negative life outcomes such as depression, anxiety disorders. But now, a new study has challenged this view.
Researchers studied infant monkeys from four different rearing conditions to examine how social context and different forms of early adversity interact with genotype to influence behaviour.
Animals reared in small social groups were more likely to be aggressive and anxious, particularly among those with a low activity MAOA genotype.
However, no genotype effects were evident in monkeys reared in larger social cages.
There are some circumstances in a child's development - such as abusive parenting - that everyone would agree constitutes "adversity."
However, this study suggests that other, subtler features of the broader social environment influence development, and that genes that affect our behavioral responses are sensitive to these influences.
So even though an infant may be reared with its nurturing mother, the relative absence of other social partners, for both the mother and the infant, can result in the infant developing an anxious style of responding to challenges, particularly if it possesses a "risky" genotype.
Of particular significance, said senior author John Capitanio, Ph.D., is "that animals that were raised in rich, complex settings with mothers, other kin, and peers, were completely protected from the potentially deleterious effects of having the 'risky' form of the MAOA gene."
The study is published in the May 1st issue of Biological Psychiatry.