Question: What is the best thing you've found/discovered about science?

Kevin O'Dell answered on 14 Jun 2014:

A few years ago we trying to answer the question ‘how do fruit flies know what sex they are?’. We used bit of gene manipulation to generate flies that were part male and part female and then looked to see who they found attractive. Because of the way the technology works these flies were predominantly male, with small regions of their brains female. So if you feminise a small part of the brain (let’s say the taste processing part of the brain) and the ‘male’ flies still find females attractive you know that for a fly, being able to process information about taste has nothing to do with how a male fly distinguishes between males and females. And so on with different parts of the brain.

One batch of our data was really interesting to us as it suggested one particular part of brain was really important as when it was feminsed in a male. In fact these partially feminised male flies found everything attractive, males, females (and to our great surprise) anything that was about the same shape and size of a fly. But the flies that did this also looked a bit odd, so we were a bit suspicious of our results.

It was only later that we discovered we’d also (and quite by accident) feminised part of the abdomen of these flies, so we’d created flies that were male but smelled like females (they made female pheromones). So any time they encountered something that looked like a fly they would also be exposed to attractive female smells from their own abdomen. As smell is the key way flies distinguish between the sexes, our males found every fly-like object attractive.

So the key point is to always do the right controls!