WASHINGTON: In a study that sheds light on the biology of aggression, scientists swapped genes in gender-bending fruit flies to make boys fight like girls and girls fight like boys.

Researchers from Harvard Medical School and the Institute of Molecular Pathology in Vienna focused on a gene in fruit flies dubbed “fruitless” an important player in behavioural differences between the sexes of these insects.

The gene is known for its role in male courtship, but also controls another sex-specific behaviour -- how flies fight, according to the research appearing on today in the journal Nature Neuroscience.

When they fight, female fruit flies rely on maneuvers like shoving and head butts to an opponent's body. Males use tactics that include lunging, boxing and rearing up on their back legs and snapping down their forelegs to flatten an adversary.

The researchers swapped the male and female versions of the gene in fruit flies and observed the consequences.

Males with the feminine gene used female fighting tactics, while the females with the masculine gene fought like the boys.—Reuters