As described in an Emory Report, sept.1999, the determining influence
of vasopression in male social and reproductive behaviors in voles,comes
not from the amount of hormone present, but rather the distribution of
the hormone receptors. A pair of scientists from the Center of Behavioral
Neurosceince, Larry Young and Tom Insel, have found that between mice species
the receptor distribution varies widely. There is marked contrast between
monogamous and polygamous species.
Because vasopressin has shown to play a role in male social behaviors Young and Insel decided that in monogamous prairie voles, a long DNA sequence inserted in the receptor gene's promoter region, is the key to their unique social behavior. In the solitary but promiscuous mountain and meadow vole this DNA insert is missing. In order to determine the importance of this gene Young and Insel placed this long DNA insert into the genome of mice, which are by nature less social and more promiscuous. The resulting transgenic mice had vassopressin receptors identical to the prairie voles and responded with increased social behavior and single female preference, that mirrored prairie voles.
Tom Insel remarked on this saying," What is really intriguing about this is that a change in the promoter sequence of a single gene can lead to a new pattern of receptor expression in the brain and then result in this profound difference in something as complex as social behavior."
Insel and Young hope to study the variations of receptor genes in humans and their effects on behavior. This could lead to improved understanding and treatment for such disorders as autism and schitzophrienia,which often result in isolation and detachment.