Friday, August 20, 1999 Published at 13:34 GMT 14:34 UK
Geneticists make faithful mice
The prairie vole gene made the mice more faithful
Scientists have transformed promiscuous male mice into more faithful partners and doting dads by inserting a single gene from a prairie vole.
Tom Insel and Larry Young, at Emory University, have also recently done related studies in non-human primates and now plan to focus on humans.
Progress for mental illness
Virtually every kind of human mental illness is characterised by abnormal social attachments, but very little is known about the role that genetics has on forming social partnerships.
"In psychopathologic disorders, there is a severe deficit in social behaviour and there could be genetic factors involved," Dr Young said.
"But it takes a lot of time to move from animal research into humans," Young warned. "And in human cultures we may find that experience and values have a lot more to do with behaviour."
Partners for life
The experiments, published in Nature magazine, used a gene from the prairie vole. Males of this rodent are faithful partners and attentive fathers.
"After mating, the male prairie vole forms a strong social bond. He prefers to be with that mate to the exclusion of all others," said Dr Young. "That pair nests together. When she has her babies he spends as much time with those babies as she does. He also defends the nest and they stay together for the next litter and the next and the next."
By contrast, the male mice used normally abandon the female immediately after mating and have no role in raising their offspring.
But by transferring a gene from the voles to the mice, the male mice became much more sociable to their mates, although occasional "extra-marital" affairs did still occur.
Patterns of the brain
The gene determines the pattern of particular hormone receptors in the rodent's brain. The hormone here is called vasopressin and was already known to have an effect on male social behaviours such as aggression and communication.
Although a multitude of genes are likely to be involved in the evolution of monogamy, this work begins to identify the links between DNA sequences, brain chemistry and social behavior.
"Perhaps it will turn out that mutations in this same gene have occurred many times in evolution, leading to alterations in patterns of social interaction and facilitating monogamy under special socio-ecological conditions," Dr Insel added.
Photographs: Larry Young