“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.