The imprinting only renders offspring more vulnerable

Nov 30, 2006 11:14 GMT  ·  By

A new research shows that the "battle of the sexes" between genes, considered the major driving force in a baby's development, might not be conformed to the reality.

A team at The University of Manchester's Faculty of Life Sciences says the maternal and paternal genes in the unborn offspring rather cooperate in a parental teamwork, that being the only way to explain some offspring traits.

"When we are conceived we inherit two copies of every gene - one set from our mother and one from our father," explained Dr Jason Wolf, lead researcher.

"But some genes - through a process called genomic imprinting - only use one parent's copy; the spare copy from the other parent is silenced by a chemical stamp."

The imprinting has long puzzled scientists as it is a paradoxical phenomenon, because it undermines the natural benefits organisms gain from inheriting two sets of genes.

If one counterpart in a gene duo is damaged, for instance, then the second gene can compensate; imprinted genes lose this assurance and therefore, are more vulnerable to disease.

Errors in imprinting have also been linked to cancer and other genetic disorders.

Scientists have long thought the reason some genes get imprinted is due to a conflict between paternal and maternal interests.

Males have the interest to produce large offspring to give them the best chance of survival and outcompeting rival males in order to widespread their gene line.

But large offspring suck a larger amount of maternal resources, so females will try to impose a genetic stamp so that smaller young are born.

"The idea that imprinting evolves because of conflict between males and females over maternal investment in their offspring has become a generally accepted truth that has remained largely unchallenged," said Wolf.

"But we have shown that selection for positive interactions between mothers and their offspring, rather than conflict, can produce the sorts of imprinting patterns we see for a lot of genes."

"For example, during placental development the maternal and offspring genomes have to work together to produce a functional placenta. By expressing the genes they get from their mothers, the offspring are more likely to show an adaptive fit with their mother's genes; they complement each other and so work better together to produce the placenta."