Mother's love can manipulate genes
February 15, 2007
*Maternal care is so powerful it can change our genetic make-up, writes
Ian Sample in London.*
A GOOD dose of motherly love may be enough to alter our genetic code,
leaving us less fearful and stressed-out in later life, researchers have
The striking claim suggests that rather than our genetic blueprint being
fixed before birth, our bodies can tweak their biological book of
instructions, allowing us to adapt more swiftly to a changing world,
instead of waiting millions of years for evolution to take its course.
If the finding is confirmed it could lead to dramatic insights into the
effects of upbringing and life experiences on a vast range of medical
conditions, including obesity, diabetes and depression.
The discovery follows tests in rats in which newborns were raised by
mothers who spent different amounts of time licking and grooming their
young. Researchers have long known animals brought up with a lot of
maternal care are less easily frightened and more adventurous. The
tests, by a team of geneticists at McGill University in Montreal, show
that motherly care has its calming effect by altering the expression of
a gene that governs the brain's response to stress.
The genetic tweak leads to more stress receptors growing in part of the
brain called the hippocampus, which together act to dampen down the
body's reaction to stressful situations. Later tests suggested the
genetic changes were long-lasting and were even passed to future
The study, published in the /Journal of Neuroscience/ this week, is the
latest in the field of epigenetics, which describes how each of the
genes we inherit is tweaked by the molecular equivalent of a volume
control, with some being silenced and others being flicked into overdrive.
A co-author on the paper, Moshe Szyf, said the changes were, in effect,
a fast-track way for the body to fine tune itself to its surroundings.
"The fact that the social environment can change genes in a very stable
manner has immense implications if it's true for humans," Dr Szyf says.
"By moving people from one environment to another you might completely
reprogram their genome and cause either positive or negative effects on
them later in life."
Anything that caused a regular, long-term release of chemicals in the
brain, from extended bingeing to a sustained bout of sexual activity,
might lead to epigenetic changes. Previous studies have hinted that
starvation in malnourished babies may lead to similar changes that alter
their metabolism, predisposing them to obesity in later life.
The changes witnessed in the rat tests make sense, a geneticist at
Cardiff University, Rosalind John, says. A mother raising its young in a
dangerous environment might devote less time to grooming them, so the
young will become more fearful --- a life-saving trait if there is a
grave threat from predators.