For Fruit Flies, Gene Shift Tilts Sex Orientation - New York Times

For Fruit Flies, Gene Shift Tilts Sex Orientation - New York Times: "When the genetically altered fruit fly was released into the observation chamber, it did what these breeders par excellence tend to do. It pursued a waiting virgin female. It gently tapped the girl with its leg, played her a song (using wings as instruments) and, only then, dared to lick her - all part of standard fruit fly seduction."
The observing scientist looked with disbelief at the show, for the suitor in this case was not a male, but a female that researchers had artificially endowed with a single male-type gene.

That one gene, the researchers are announcing today in the journal Cell, is apparently by itself enough to create patterns of sexual behavior - a kind of master sexual gene that normally exists in two distinct male and female variants. ..

The results are certain to prove influential in debates about whether genes or environment determine who we are, how we act and, especially, our sexual orientation, although it is not clear now if there is a similar master sexual gene for humans.

Still, experts said they were both awed and shocked by the findings...

The finding supports scientific evidence accumulating over the past decade that sexual orientation may be innately programmed into the brains of men and women. Equally intriguing, the researchers say, is the possibility that a number of behaviors - hitting back when feeling threatened, fleeing when scared or laughing when amused - may also be programmed into human brains, a product of genetic heritage....

All the researchers cautioned that any of these wired behaviors set by master genes will probably be modified by experience. Though male fruit flies are programmed to pursue females, Dr. Dickson said, those that are frequently rejected over time become less aggressive in their mating behavior.

When a normal male fruit fly is introduced to a virgin female, they almost immediately begin foreplay and then copulate for 20 minutes. In fact, Dr. Dickson and his co-author, Dr. Ebru Demir of the Institute of Molecular Biotechnology, specifically chose to look for the genetic basis of fly sexual behavior precisely because it seemed so strong and instinctive and, therefore, predictable. ...