RESEARCH Nurture has one up on nature
Rat study suggests that parenting affects genes.
LONG ISLAND NEWSDAY
MELVILLE, N.Y. -- For the first time, scientists have demonstrated that nurture can alter nature.
Different mothering styles can literally change the activity of specific genes that in turn govern the way the brain responds to stress, according to researchers at McGill University in Montreal. These effects, which occur as early as the second week of life in a rat, are still present in adulthood, the researchers said.
Ian Weaver, a co-investigator with Michael Meaney, Moshe Szyf and their colleagues at McGill, said that adult male rats who as pups had received licking and grooming from their mothers recovered much faster from a stressful event than those who hadn't experienced a lot of nurturing. The study is published in this month's Nature Neuroscience.
The researchers wanted to understand how genes respond to nurturing environments and whether that alters the way an animal responds to stress later in life. They looked at changes in the molecular processes in adult rats whose mothers had licked and groomed them, and compared them to adults whose mothers had shown little interest in their pups' grooming.
Long-term effects
Weaver said the brains of the adults showed signs of change based on the attention the pups received from the mother.
And the animals that received such attention were also more explorative and less anxious.
"Although we have known for years that early experience -- whether positive or negative -- can have long-term effects on behavior, the mechanism has not been previously described," said Thomas Insel, director of the National Institute of Mental Health in Bethesda, Md.
Weaver suspects that the mechanism that they have identified is the body's genetic memory of mothering. This memory is believed to play a role in defining one's experience later in life.
The human equivalent of licking and grooming is cuddling, nurturing and instilling a sense of confidence and love, the scientists said. But they added they don't understand how the animal finding fits into human experience.
The study involved more than 100 rats in various experiments.