In theory, these low-scoring proteins might not have been studied because they don’t do anything important. To get an idea of whether the proteins matter, the team used a technique called RNA interference (RNAi) to reduce the levels of 260 proteins with scores below 1 in fruit flies. In 60 cases, the flies died, showing that these particular proteins have an essential function.
That was a big surprise to the members of the team who study fruit flies, says Munro. “They just assume that every possible important gene has been found, which turns out, of course, not to be true.”