New submitter Fiona_OHanlon writes: According to an article at Ars Technica, researchers injected enzymes into ant larvae brains, causing genetically identical ants from different castes to behave as if they were from the opposite caste. From the story: "Carpenter ants live in a caste system, where some members of the colony grow into large, strong worker guards known as majors and others grow into small, inquisitive food scouts known as minors. [The researchers] focused specifically on enzymes that affect 160 genes whose activity diverged the most between minors and majors. Those genes included ones associated with learning, memory, and the way neurons communicate with each other in the brain. ... After several experiments with feeding the substance to their insect subjects, the researchers figured out how to inject the enzymes into the brains of major workers shortly after hatching (abstract). The treatment made the ants take on new social roles immediately. ... The modification ultimately depended on changing the behavior of one particular gene, Rpd3, which set off a cascade effect that changed the behavior of other genes too."