In honey bee colonies, the queen reproduces; workers do not. This division is not genetic — queens and workers share the same genome. The difference is environmental: larvae fed royal jelly develop into fertile queens; larvae fed worker jelly develop into sterile workers. The mechanism by which diet produces sterility was known to involve juvenile hormone, which is higher in queen-destined larvae. But how a hormone level translates into the physical destruction of ovarian tissue — the programmed cell death that eliminates a worker's reproductive potential — had no identified intermediary.
Published in PNAS, researchers identified lncov1, a long noncoding RNA that is upregulated in ovaries with reduced reproductive potential. Low juvenile hormone in worker larvae promotes high lncov1 expression; high lncov1 expression correlates with extensive programmed cell death in ovarian tissue. The same RNA responds to queen pheromone in adult workers, maintaining sterility throughout life. The environmental signal (diet, pheromone) sets the hormone level; the hormone level sets the RNA expression; the RNA expression determines whether ovarian cells live or die.
The structural insight is about the nature of the intermediary. lncov1 does not encode a protein. It is not translated into a functional molecule that acts on the ovary. It is a regulatory text — a piece of RNA whose expression alone is sufficient to trigger a developmental cascade. The sterility program is written in a molecule that does nothing except exist in the right quantity at the right time. The information is not in what the RNA does but in how much of it there is. Quantity is the message.