Washington, Nov 4 : Parents don't take up children's duties on their own, it's the genes that guide them to take up different roles in kids' upbringing, finds a new study, which establishes the fact that different roles of mothers and fathers are influenced by genetics
Conducted by the Universities of Exeter and Edinburgh, the study shows how variation in where males and females put their parenting effort reflects different genetic influences for each sex.
The study, based in the burying beetle, Nicrophorus vespilloides, can be applied to other species and possibly humans, said the researchers.
Specialised male and female roles are common in species in which both parents take responsibility for raising offspring.
In beetles, females tend to spend more of their time directly caring for the offspring through feeding, which involves regurgitating food directly into begging mouths, like birds. Males indirectly help their young by preparing food and taking care of the nest.
"Despite the best efforts of parents to be consistent in child rearing, it is not unusual for mums and dads to differ in the nature of their interactions with offspring. In the case of humans, until recently this was expressed as dad bringing home the bacon and mum taking care of the kids," said lead author Professor Allen Moore of the University of Exeter.
He added: The same pattern holds in many animals where both parents help rear the offspring - mothers often directly care for the young while the father takes care of the nest or brings home food for the family. But why should parents specialise? Why don't they share the duties equally? Previous studies suggested that specialising is efficient. But why a particularly specialty for mums and dads? Why not work it out family by family? In this study we examine the genetic influences on parenting for the first time, and ask if different parenting styles are inherited."
In the study, the researchers collected burying beetles in Cornwalla and bred them over three generations, and then separated them to compare the roles taken by a single mother and a single father.
It was found that females focused their efforts on providing direct care for their young whereas males were more inclined towards indirect care.
Thus, males and females working separately focused on the same roles they would adopt if they were raising their young together. And, the differences reflected genetics.
The researchers discovered that these differences have evolved because there is a genetic correlation between sex-specific parenting traits and the number of offspring parents choose to raise.
Professor Allen Moore concluded: "We were somewhat surprised by our results. Males and females share the same genome so these differences in genetic influences between the sexes had to evolve from the default of no differences between the sexes. This occurred because of sex differences in shared genetic influences on other traits. But the evolution of this specialisation also helps reduce conflicts between the parents and form an efficient family unit, reinforcing the genetic differences between the sexes."
The study is published in the journal Proceedings of the National Academy of Sciences.