Lotharios tamed by brain proteinCould gene therapy cure promiscuous
|Prairie voles (top) like
to huddle, unlike solitary meadow
Want to tame the eye of a philandering love rat? Then
help is at hand. New research shows that gene therapy
can turn promiscuous male voles into faithful
Miranda Lim from Emory University in Atlanta,
Georgia, and colleagues used a virus to introduce a gene
directly into the brain of male meadow voles
(Microtus pennsylvanicus). The gene encodes a
protein called the vasopressin receptor, which helps to
regulate social behaviour and pair bonding.
A few days later, the normally promiscuous rodents
developed high levels of vasopressin receptors and lost
their lust for the ladies. The results are reported in
this week's Nature1.
The animals' brain chemistry and behaviour resembles
that of their relative, the monogamous prairie vole
(Microtus ochrogaster). These faithful creatures
mate for life and have many vasopressin receptors in the
ventral forebrain, a brain region known to regulate
addiction and reward.
Increasing the number of vasopressin receptors in
this area gives an animal a sense of reward when it
forms a close pair bond, explains Lim. So lecherous
animals calm their errant ways.
"It's amazing to think that altering just one gene
can regulate such a complex behaviour," says Lim.
Lim's team paired male prairie and meadow voles with
a sexually receptive female of the right species. Each
pair was allowed a day to get to know each other, then
the males were given a fidelity test.
Each vole was allowed to wander freely between his
tethered partner and a tethered stranger. Prairie voles
and genetically modified meadow voles huddled close to
their partner; untreated meadow voles preferred to spend
Earlier work has shown that boosting vasopressin
receptor levels speeds up pair bond formation in
monogamous voles. The new research shows that a similar
technique can turn a promiscuous species of vole into a
This has implications for species evolution. "The
study suggests that promiscuous species may harbour the
potential to engage in pair bond formation," says
Whether or not the technique could work in humans is
not known. Promiscuous and monogamous monkey species
have different patterns of vasopressin receptor
expression that closely match those seen in the voles.
So it is possible that philandering and faithful humans
may share similar brain chemistry, says Lim.
But pair bonding in humans is more complex, cautions
psychologist Evan Balaban from McGill University,
Montreal, Canada. Social factors, economics, history and
individual differences all play a role.