Neat. Link
Turns out that in fruit flies at least, it is linked to perception of scents and some other factors. Another nail in the coffin of the old homosexuality is a learned behaviour argument. 
If you turn it off, are they still fruit flies?
When I was in grad school, a student submitted a mock proposal on the subject. It was interesting to see what happened when such a socially and politically charged subject is discussed with dispassionate scientific jargon.
For example, when you restore wild-type function to a mutant, you’re said to “rescue” the phenotype. I have to admit, I raised an eyebrow when the student described “rescuing” flies by making them heterosexual.
That seems like a massive stretch of assumption. Fruit flies are pretty different from humans, or just mammals, or just vertebrates - is there even any evidence that the phenomenon described as homosexuality here in fruit flies is in any way related to the phenomenon of homosexuality in humans, other than the outward fact that it appears to result in attempted copulation with the same sex?
Unless I’m missing it, I think there is an alternate explanation. The only mention of the courtship behavior in these gb flies is this:
“Based on a striking increase in homosexual courtship displayed by gb mutant flies (Grosjean et al., unpublished results), we named the predicted gene CG6070"genderblind.”
I would sort of like to see how they did this experiment, but it isn’t discussed in the paper in J. Neurosci. It seems like all they did was put the male flies into tubes with other male flies and note that the gb flies are copulating with same sex partners more often than wild type flies in the same situation.
The correct way to do this experiment is to put the gb flies with 50% male flies and 50% female flies and measure whether they have an increase preference for the same sex flies; that would be more akin to human sexuality than if they are merely unable to differentiate male from female (the flies, not the people!).
Again, they might have done it this way, but it doesn’t sound like it and the methods are not outlined in the methods section.
At least if I were a reviewer…
(not doubting that homosexuality is biological, merely doubting that this study is conclusive)
Not so different as you might think.
Not to mention that 70% of genes found in the flies are found in us. Cite. True we’re a mite bigger, and a mite smarter, and we don’t have wings, but we’re similar in a lot of ways.
I’m thinking that behaviour probably isn’t all that high on the list of ways in which we’re similar.
I agree with Fiveyearlurker - I don’t deny a genetic component to homosexuality in humans, but I just don’t think this demonstrates it - and I think leaping to that conclusion does more harm than good to the argument for a genetic component.
Hey I actually did a talk on this subject! Not this paper in particular though.
There’s been a whole host of genes identified in fruit flies that affect sexual behavior–hermaphrodite, doublesex, and most notably fruitless (har!). Some of these also affect external sexual structure morphology to varying degrees, so it’s not clear that these flies are really “gay” so much as you’ve affected sexual differentiation. IIRC, fruitless was a notable exception in that the flies were morphologically male, but engaged in male-directed behavior. Turned out the fruitless mutation affected a sexually dimorphic ganglion in the fly brain that was responsible for regulating this type of behavior.
Now.
Find me that ganglion in the human brain.
Humans are way more complex, and I wouldn’t jump all over this and say “Ergo, this is why humans are gay.” I do think it suggests that sexual behavior (hell, behavior in general) is biologically determined, and that humans, while more complex than flies, are still governed by deterministic molecular factors. But that’s just the paradigm that I operate from in general.
I wouldn’t say that either, but any good reproduceable scientific research that demonstrates a concrete biological reason for homosexuality is excellent. Hopefully, the weight of the evidence will eventually squash the cultural bigotry.
Why? We need to be completely dispassionate when doing science. If you want a certain outcome, you’re not doing good science. If it turns out that being gay is not biological in nature, that’s neither good nor bad. We figure out where we go from there.
That being said, I think most of the evidence we have to date make the biological hypothesis much more likely. But we’re not quite at the point of knowing.
It is just easier on the whole if it IS a biological factor. Would it not be nice if we KNEW that it simply was the way that someone was born, like blue eyes or red hair? It certainly would go a long way to helping to eliminate the cultural problems that we still wrestle with regarding the issue.
I don’t want it do be any different than it is. I can’t imagine wanting reality to be something that it isn’t. Maybe I’ve just been doing science too long.
In fact, I suspect your own bias has shaped the way you are interpreting this data.
Would it? Lets say we had a complete understanding of the genetic basis of sexuality, such that we could predict a fetus’s future sexuality with reasonable accuracy in utero. You don’t forsee some uncomfortable implications of the availability of that knowledge in this sociopolitical climate?
Which is not to say that I think such a thing is possible, feasible, or desirable but to say that understanding the biology of this will cure all of the social misunderstandings regarding homosexuality is absurd.
Personally, I would VERY MUCH like to know how to persuade successive generations of fruit flies in my house to be homosexual. There would be many less of them in a few days, and the ones that were left wouldn’t be nearly as insistent on watching NASCAR.
Sorry, had to be done. Really do have a fruit fly infestation.
It would be interesting if you could predict, with close to 100% accuracy, genetic predisposition to homosexuality, but it proved very difficult to affect the outcome (sort of like baldness - we’re fairly sure why it occurs but can’t do much about it to this point). Especially since the folks who are most fervently anti-homosexual are often the most fervently anti-abortion. Might make them change one view point or the other.
Certainly it has, but I am not a scientist doing research on the issue. Frankly, I can not imagine anyone researching anything simply for the sake of it. Nor anyone receiving funding for pure, non applicable studies either. Most research is conducted with some idea of the eventual applications or ramifications of the results. Good science is conducted without bias, but as an end user of results I don’t have review it as dispassionately.
The data to me simply says that in fruit flies at least there certainly is a biological component to sexual behavior, cool beans. That means to me that we probably are not too far away from demonstrating the same sorts of interactions in vertebrates. Then mammals, then hominids and so on. That has huge ramifications for us as a species and how we view and deal with homosexuality.
I never said it would be a panacea for all of society’s woes regarding homosexuality, only that such knowledge would be of great help in forwarding acceptance and dissuading intolerance. It would invalidate the “you chose to be gay” camp’s argument entirely.
It’s true that strong knowledge of a deeply ingrained biological basis for homosexuality would go a long way towards societal acceptance of homosexuality. Which is kind of sad. Personally, I would love to see a world where people felt that, even if homosexuality had no biological basis, even if it was, of all things, a completely conscious choice(!), there would still be nothing wrong with it.
Not necessarily. For instance, we’re a lot more closely related to alligators than fruit flies. A lot more closely. And yet alligators use temperature to determine the sex of their offspring, not genes.
Although the evidence for a biological basis for human sexual orientation is very strong, we’re can be pretty certain that it isn’t genetic (or not wholly genetic). And if we do find a simple biological basis, like genetics, then are you going to jump for joy when people start aborting babies with the “gay gene”? Or, if parents give anti-gay drugs to children who exhibit signs of being gay?
Any answer is going to generate problems. It’s not the particular mechanism that creates the problems but what we do with the knowledge.
bolding mine
That is absolutely true.
Here is where I am certain to get flamed, No I wouldn’t have any more of a problem with the termination of a “gay” pregnancy, then one for any other reason. Further, if gene therapy, or a drug could be developed to give those people who do have serious issues with their sexuality a chance at trying the other side of the fence, I have no issue with that either.