A June 3, 2005 article in the New York Times, "For Fruit Flies, Gene Shift Tilts Sex Orientation," by Elisabeth Rosenthal of the International Herald Tribune , stated:
"In a series of experiments ... researchers found that females given the male variant of the gene [the fruitless (fru) gene] acted exactly like males in courtship, madly pursuing other females. Males that were artificially given the female version of the gene became more passive and turned their sexual attention to other males....
That one gene, the researchers are announcing today [June 3, 2005] in the journal Cell ("Fruitless Splicing Specifies Male Courtship Behavior in Drosophila," Vol. 121 pp. 785-794), 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....
'We have shown that a single gene in the fruit fly is sufficient to determine all aspects of the flies' sexual orientation and behavior,' said the paper's lead author, Dr. Barry Dickson, senior scientist at the Institute of Molecular Biotechnology at the Austrian Academy of Sciences in Vienna. 'It's very surprising. What it tells us is that instinctive behaviors can be specified by genetic programs, just like the morphologic development of an organ or a nose.'" June 3, 2005 NY Times
In the journal article "Fruitless Splicing Specifies Male Courtship Behavior in Drosophila," published June 3, 2005 in the journal Cell (Vol. 121, pp. 785-794 - see full article in PDF), researchers Demir and Dickson wrote:
"We show that male [gene] splicing is essential for male courtship behavior and sexual orientation. More importantly, male [gene] splicing is also sufficient to generate male behavior in otherwise normal females. These females direct their courtship toward other females (or males engineered to produce female pheromones).
The splicing of a single neuronal gene thus specifies essentially all aspects of a complex innate behavior." June 3, 2005 Cell