Genetic variation persists through generations, rather than being bred out in an evolution towards a “perfect type”, shows new research from Australian National University.
A combined field and theoretical study on the breeding behaviour of European bank voles – a small mouse-sized rodent common in Europe and Great Britain – has been carried out by researchers at ANU and colleagues from Finland and France.
The team observed that males which carried the genes for behavioural dominance were more successful at winning mates. However, their gene-sharing female siblings were less successful, having smaller litter sizes. In contrast, females that didn’t carry the genes for behavioural dominance had larger litter sizes.
This phenomenon is called sexual antagonism – where a particular gene is beneficial for one sex, but decreases success for the opposite sex.