The age of puberty in girls is affected by the kind of “imprinted” genes that they inherit from their mothers and fathers, suggesting that one or other of the parents has a bigger than expected influence on the age of a daughter’s sexual maturity.
Findings from an international study on more than 180,000 women identified 123 genetic variations associated with the timing of when girls experienced their first menstrual cycle.
Six of these variants were clustered within the imprinted regions of the genome which means they are switched on or off depending on whether they are inherited from the mother or the father.
“Normally, our inherited physical characteristics reflect a roughly average combination of our parents' genomes, but imprinted genes place unequal weight on the influence of either the mother's or the father's genes,” said John Perry of the Medical Research Council Epidemiology Unit at Cambridge University.
“Our findings imply that in a family, one parent may more profoundly affect puberty timing in their daughters than the other parent," said Dr Perry, the lead author of the study published in the journal Nature.
Some of the genes are only active when inherited from the father, some only active when inherited from the mother and as both types affect the timing of puberty, it indicates a “biological conflict between the parents over the child’s rate of development”, the study suggested.