Researcher Links Maternal Genes to Selfish Behaviour

Úbeda, along with fellow evolutionary biologist Andy Gardner from Oxford University, examined the impact that genomic imprinting has on the carrier's selfish or altruistic behaviour. Genomic imprinting is the phenomenon in which the expression of a gene depends upon the parent who passed on the gene. Every person has a set of chromosomes from each parent but due to imprinting, a particular gene is inactivated.

Úbeda and Gardner developed an evolutionary mathematical model that examined the consequences of ancestral women's tendency to follow their mates and raise their children among people they are not related to. They found this behaviour spurs a conflict between mom and dad genes in a juvenile over how it should act in society.

"Because the child's dad stayed put, the genes the child gets from dad are more likely to be present in her neighbours. The genes telling her to be nice to neighbours (genes for altruism) will be dad genes. Because her mom moved around to be with dad, and thus is not related to the other villagers, her maternal genes will be telling her to be mean to neighbours," Úbeda said.

Therefore, if a child finds an apple, her paternal genes will tell the child to share it with other children in the village, since the other children are likely to be relatives. Her maternal genes, will say 'keep the apple for yourself.' This research applies to all societies where females migrate more than men or vice versa. It is this demographic inequality that makes it more likely that children who are helpful to others are related through their father's genes, not their mother's genes.

The findings can also be used to interpret neurological disorders. Recent research links mutations resulting in greater expression of paternally inherited genes or maternally inherited genes to psychiatric disorders such as autism or psychosis, respectively.

"The model makes clear predictions that the social structure in which individuals evolved can affect clinical phenotype and the severity of these neurological disorders," said Úbeda. "It implies that a mutation in an imprinted gene will result in the reverse clinical phenotype when the mutation is inherited via sperm or via eggs."; Source: University of Tennessee at Knoxville