edited down from: http://www.balloon-juice.com/ The cutesy names, `cheapdate' and so on, are the names of genes. See http://afone.as.arizona.edu/~cary/fnjm/barflies.jpg for the Inebriometer. By now it should be clear why a young scientist who wanted to uncover the basic genetics of inebriation, alcoholism and alcohol tolerance chose to work with fruit flies. There's a bit more -- on top of fruit flies being a great genetic model, people and flies both have a history of alcohol consumption that stretches back over evolutionary time (read more about that here ) and we have nervous systems that largely work in the same way, so there's reason to expect that we and they will respond similarly. As Heberlein noted recently: It became immediately apparent that the behavioral changes elicited by acute ethanol exposure are remarkably similar in flies and mammals. Flies show signs of acute intoxication, which range from locomotor stimulation at low doses to complete sedation at higher doses and they develop tolerance upon intermittent ethanol exposure. [Heberlein et al. (2004) Integrative and Comparative Biology 44:269-274] You cannot tell fly researchers apart based on how they make mutations -- there are only a few more-or-less standard ways to insert random mistakes into a fly's genome -- and once one identifies a mutation the procedures for tracking down where exactly the mistake happened are more or less standard. The real magic is in the behavioral assays that fly-pushers come up with to select mutations they want out of thousands and thousands of randomly-mutated flies. Folks searching for the genes controlling flight will look for flies that can't reach an elevated food trap while folks asking which genes control memory will test to see which flies can't learn to choose only the food that does not carry a mild electric charge. In a search for mutants that got drunk unusually fast Heberlein built the inebriometer. Heberlein's device (B) basically amounts to an alcohol vaporizer (A) connected to a column of funnels stacked on top of each other. Flies start out in the space at the top of the column, but as the effects of demon rum set in they lose their coordination and drop into the next column, and then the one after that, and so on. Eventually the drunkest flies reach the pass- out stage and drop through straight to the bottom. The first fly to drop out of Heberlein's inebriometer, the appropriately- named cheapdate mutant, barely needed the fly equivalent of a Kahlua shot before it folded it up its wings and dropped. Cheapdate unexpectedly mapped to a protein called amnesiac, so named because amnesiac mutant flies show a total block in tests for learning and memory. More mutants originally known for their defects in memory and learning -- rutabaga and fasciclin II -- went throught the inebriometer and dropped out almost as fast as cheapdate. These results suggest that the same proteins which keep our gin-soaked brains operating are actually moonlighting from their regular job as mediators of memory. The amnesiac gene encodes a neurotransmitter while rutabaga makes a protein involved in the cyclic-AMP signaling pathway . More mutants have been identified but haven't yet been characterized to the same degree as cheapdate: lightweight has the same effect as cheapdate but acts on a different gene, while barfly and tipsy have opposite effects in the inebriometer, the former making flies more resistant to alcohol and the latter making them sensitive. Unlike cheapdate and lightweight, barfly and tipsy influence alcohol's sedative effect instead of its impact on posture and coordination. Like any good research the work by Dr. Heberlein and others raises ten questions before it gets close to answering one. Does a drinking binge swamp the cAMP signaling pathway so badly keeping our soaked brains functioning that it can't keep up with its usual job of making memory? Could be. Dr. Heberlein has already made the leap from flies to mammals, so we may know much more soon.