“Male-male courtship might have been common in the ancestral D. melanogaster population,” Long said. “Sphinx appears to have evolved to reduce this in one single species.” By silencing this gene, the researchers may have generated an ancestral genotype that existed before sphinx originated.
D. melanogaster separated from related species about three million years ago, the researchers say. Male-male courtship could have been common among the fly’s ancestors before that separation up to at lease 25-30 million years ago.

“Species that don’t have this gene show more male-male courtship behavior than those that do have it,” Long said. “The absence or presence of the sphinx gene appears to regulate the diversity of male-male courtship behavior among flies. This suggests that the genetic control of male courtship is an evolving system, which can recruit new genetic components and change courtship behaviors.”

“This is the genetic interpretation,” Long said. “Of course other factors, like the environment, are also likely to have an influence.”

The newest contribution in this field — published in the PNAS.

Male and female brains are not so different, fruit flies’ sex acts tell us

Study in flies points to unisex brain

Remote control of fruit flies’ sexual behaviour has revealed that male courtship tricks lie dormant in the female brain.

‘You might expect that the brains of the two sexes would be built differently, but that does not seem to be the case,’ says Miesenböck. ‘Instead, it appears there is a largely bisexual or “unisex brain” with a few critical switches that make the difference between male and female behaviour.’

‘The fact that we could make females vibrate one wing to produce a courtship song – a behaviour never before seen in female flies – shows that the brain circuits for this male behaviour are present in the female brain, even though they are never used for that purpose,’ says Miesenböck. ‘One obvious question is why females possess this brain circuitry at all. It’s possible that the circuitry overlaps with circuitry used for other behaviours.

‘But the mystery at the root of our study is the neuronal basis of differences in male and female behaviour. Anatomically, the differences are subtle. How is it that the neural equipment is so similar, but the sexes behave so differently?

‘Our findings suggest that flies must harbour key nodes or “master switches” that set the whole system to the male or female mode. Our next goal is to find those controls.’ In an earlier study in mice, other researchers found that females took on masculine behaviours when a particular pheromonal cue was blocked, suggesting that male behaviour is actively repressed in the rodents.

‘In flies, you don’t see a spontaneous emergence of male behaviour when you block pheromonal cues,’ Miesenböck says. ‘Rather, it requires an artificial trigger. Female flies have the program, but they seem to lack the activating command. Either way, the principle is the same in flies and mice: male and female brains are not as different as you might think.’

Source: Oxford University

Sure, some people will choose to take a pill to become straight. So what? The bottom line is, government does not have the right to impose sexual morality, but beyond that it’s up to the individual on how they want to live their life. If such a pill is ever devised, I think it would be quite liberating.

I hope you got this nuance I’ve been trying to put across. Finding a “trigger” that can influence a condition is not finding a cause or a reason for the existence of that.

I believe we have all gotten your “nuance”. However, for all your speculation, it should be pointed out that we don’t know if we are dealing with something like a “trigger” or if it is something much larger. We have to admit we don’t honestly know the extent to which nature and nurture play a role in the shaping and understanding of our sexuality, just that they both most likely do.

It looks like it’s going that way. Even if these rats are not higher mammals, all mammals must have preserved some “legacy” mechanisms in their most basic systems. In rats, it’s the vomeronasal organ that influences the brain in gender roles (the brain is flexible in support); in humans it might be the visual input or some other sense (proprioception, maybe?) influenced by a “trigger”, a chemical compound (or a deficient level of it).

We tend to forget when we think about this subject that it’s not in terms of sexuality that humans are most complex, but in all other ways — tool usage, memory, awareness, reason, discernment, cooperation. Yeah, our brain is complex, as someone pointed out in a previous message, but it’s not for sexuality or gender behaviour that is known to have evolved so much. So I expect this issue to not be susceptible to the same degree of complexity as the ‘modern’ abilities. Helen Fisher developed a model of mammal reproduction valid for humans too, with all the neurological implications.

Jag,

I stated my position, I still believe you were unduly intransigent on the “ex-gays marrying women” and ostensibly neutral on whatever minorities may want to get married for. We can agree we disagree. The message is here for people to judge for themselves.

On the pill question — I have already tried to make it clear that whatever we may understand by “biological support” can be a matter of great complexity. Biological support does not mean necessarily cause, or not mainly that. Some conditions have psychological causes but are supported by chemical reactions, you alter the chemistry, you change the course of that condition without knowing if it’s really genetic, epigenetic or otherwise developmental. I hope you got this nuance I’ve been trying to put across. Finding a “trigger” that can influence a condition is not finding a cause or a reason for the existence of that.

Two things –

One, you will note that I am not inconsistent…as per Ken’s comments above. Please reread – you seem a bit confused.

Secondly, a “pill” to change orientation would indeed solidify the biological argument…that doesn’t mean that biology is the ONLY contributor, but that there is a component which is biological in nature. Even that simple truth (which is evident in science today) is denied by many.

Evan, please reread my posts and I encourage you to ask questions before becoming accusatory. If you find an inconsistency (or think you have) – please ask me about it…I’d love to clarify so I am not misunderstood, or misrepresented by others.

That is a great story and I believe it gives us a strong clue as to how SSA is going to play out. One chemical probably seperates gay and straight. Depending on someone’s genetic makeup it might have an impact on personality and gender identity as well.

On a related note, MTF Transexuals claim that they have female wiring stuck in a male body. It might turn out that EVERY man has female wiring. Most men produce the specialized hormones that turn it off but for some reason transpeople don’t produce these chemical messengers. It looks like it might be headed that way.

David Featherstone, one of the scientists who participated in that study on shifting Drosophila mating behaviour, mentioned a most interesting study on mammals published in August this year.

The Harvard research team which conducted the study reported that gender roles were shifted in male and female rats just by deleting one single gene, involved in detecting pheromones. The astonishing discovery is that it was not the brain that decided gender roles difference (in fact, both sexes had neural circuitry for both types of gender roles), but an organ involved in olfactory input. This is of great significance, as a theoretical progress, because up until now it was assumed that in mammals it was the brain that decided gender roles.

“There’s a major finding here,” says Dulac [from the Harvard research team]. “Sex-specific behaviors were assumed to be controlled by sex-specific neurons. We found that the brains of animals in a given species may have male and female components controlled by a switch. That switch is sexually dimorphic and modulated by pheromones.”

Dulac is careful to clarify that olfactory cues impact sexual behavior in mice much more than in humans. Like other primates, people lack vomeronasal organs and perceive the world mostly through vision. But Dulac insists that focusing on the fact that her study pertains to olfaction is missing the point. It is the switch mechanism, independent of the sensory modality, that could apply to several other species, she says. “We are shattering the dogma on the male and female brain and the major importance of testosterone.“

Here is a press report on that:
Gender Switch? Mice that can no longer detect pheromones because of a single gene deletion cross the boundaries of typical gender behavior.

I’m looking forward to findings on higher primates. I’m sure we’re going to lose some other dogmas in the process.

Every transperson I’ve ever known or heard of who found their orientation changing during transition, it happened around the first year of taking hormones or after they came out, and it was a one time thing. Str8 as guy to str8 as girl, gay as guy to gay as girl, gay as guy to bi girl, gay girl to gay guy, etc. I’d give it about a 99% chance that the transwomen Featherstone refers to is bisexual and the regular shifts she attributes to hormones and diet are psychosomatic.

Orientation shifts in transpeople are almost certainly the result of lifting psychological repression when accepting onesself as transsexual. Orientation shifts can go either way, and it doesn’t make sense that the same hormones would cause one person to become attracted to guys and another to girls.

As for gay curing pills, well, color me skeptical. The human brain is waaaaaayyyyy more complicated than the mouse or fruit fly brain. To completely shift sexual orientation would likely require a major reworking of the brain itself, and I don’t see that happening with a pill. In the highly unlikely event one was invented, I doubt it would be young people taking it, as homosexuality is increasingly no big deal among the young, and that trend is only going to continue.

He hasn’t put his two cents in for a few threads. I hope he’s doing ok.