On the causes of sexual orientation

But, Nosy, your fecundity function, as it is linked to homosexuality, can only cause a greater disproportionality in reproductive success amongst individuals of a population, which is precisely what NS is all about.”HMEdited by Hoot Mon, : No reason given.

I have no idea what you mean. Could you clarify please?

The definition of Darwinian natural selection is: differential reproductive success amongst individuals across a population. Wouldn't you suppose that homosexuality could affect that?”HM

That is precisely what the paper is talking about. You seem to have harped a lot on the negative affects of homosexuality on reproductive success. What this paper is showing is that if the genetics involved also offer some positive effects in the population as well you get a dynamic balance in the population.This is the same kind of population dynamics that goes on in malarial areas with the sickle cell gene. It is very bad (read fatal) to have two copies of this gene. However, having one copy isn't so bad but isn't so good either in non-malarial areas. In malarial areas having one copy confers an overall advantage. Thus population modeling can tell you where the population will balance out - not too many copies of the sickle cell allele but still some.This puts to rest your overly simplistic model that says if an individual doesn't breed then NS will remove the genes from the gene pool. This turns out to be wrong.

Nosy, anything that affects the reproductive success of individuals in a population will invite NS. That is true because NS is precisely defined as differential reproductive success of individuals across a population.A population experiences no NS if it comprises no differential reproductive success amongst its individuals. But if some members of a population fail to engage in successful reproduction, that means that THERE IS differential reproductive success amongst its individuals. Therefore, they contribute to the NS process by failing to reproduce.”HM

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Nosy, anything that affects the reproductive success of individuals in a population will invite NS. That is true because NS is precisely defined as differential reproductive success of individuals across a population.

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A population experiences no NS if it comprises no differential reproductive success amongst its individuals. But if some members of a population fail to engage in successful reproduction, that means that THERE IS differential reproductive success amongst its individuals. Therefore, they contribute to the NS process by failing to reproduce.

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”HM

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Absolutely. And this study has shown that homosexuality has a positive effect on reproductive fitness which counterbalances the negative one.In women, the "gay gene" appears to enhance reproduction, while in men the "gay gene" will reduce reproduction.Just as Nosy said, the analogy to the SCA gene is an apt one. Sure, a good mix of this gene in a population is going to be fatal for some individuals, but across the board it's still going to result in improved reproductive fitness.It's important to remember that populations evolve, not individuals. Some dudes not fathering children isn't going to affect the women in the population from getting pregnant and giving birth to highly fecund females and gay males.Edited by BeagleBob, : No reason given.

BeagleBob, just checking on one point here. You know that there is a difference between fecundity and NS. Fundity is a measure of a female's ability to make babies. It is not a measure of NS itself. NS happens when the fecundity of females is differentially distributed across a population. Thus, when some females become more fecund than others their population undergoes natural selection. The study cited by Nosy does not address differential fecundity, which is tantamount to NS.”HM

It doesn't??? Please explain.

Isn't the article suggesting that a population containing 'gay genes' results in higher fecundity females and thus a higher fecundity of the population as a whole?Thus it is suggesting that 'gay genes' are beneficial to the population as whole in terms of NS.Or have I misunderstood?

Nosy, from your cited article in Message 41:

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These findings provide new insights into male homosexuality in humans. In particular, they promote a focus shift in which homosexuality should not be viewed as a detrimental trait (due to the reduced male fecundity it entails), but, rather, should be considered within the wider evolutionary framework of a characteristic with gender-specific benefits, and which promotes female fecundity. This may well be the evolutionary origin of this genetic trait in human beings.
The possible widespread occurrence of sexually antagonistic characteristics in evolutionary processes, which play their evolutionary game by giving a fecundity benefit to one sex while disadvantaging the other, has only recently begun to be appreciated. This is understood as a key mechanism through which high levels of genetic variation are maintained in biological populations.

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You're right and I'm wrong on that score (highlighted in yellow). But I was pursuing a different point”one that makes a population more likely to evolve via NS, thereby affecting its genomic stasis, if it takes on homosexuality.Remember my fifth WHEREAS in the opening post: "WHEREAS; Homosexual orientation did not evolve to facilitate a population’s dynamic equilibrium or its struggle against Darwinian natural selection; in fact, it may be a mechanism that suppresses a population’s ability to resist NS." I think your article partly supports this assertion. A population can be provoked into NS by homosexuality, because it may raise genetic variation too high.As for the red conclusion: Why wouldn't higher levels of genetic variation maintained by a population be as much of a bad thing for its stasis than a good thing? I agree that some genetic variation is important to a population's stasis, but too much of it be could be corruptive. A middle ground might be that homosexuality evolved as governing mechanism for maintaining healthy genetic variation.From this article I can see better how homosexuals might help to maintain a healthy level of genetic variation in a population, if I understand the proposed mechanism. Is this the empirical evidence I've been looking for that supports a theory that homosexuals naturally play a positive role in the human population? Or is it evidence that they could tilt us on our ear?”HM

It's more likely that I misunderstood. But the question remains: How, in terms of NS, do 'gay genes' work? Do they work in favor of NS? Or do they work for the stasis of a population?”HM

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How, in terms of NS, do 'gay genes' work? Do they work in favor of NS? Or do they work for the stasis of a population?

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This is an unanswerable question as framed.Whether any characteristic is favored or disfavored during the process of natural selection depends on the environment. I have no doubt whatsoever that someone could define an environment in which "gay genes" are an advantage and could also define an environment in which "gay genes" are a disadvantage.

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Those who would sacrifice an essential liberty for a temporary security will lose both, and deserve neither. -- Benjamin FranklinWe see monsters where science shows us windmills. -- Phat

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BeagleBob, just checking on one point here. You know that there is a difference between fecundity and NS. Fundity is a measure of a female's ability to make babies. It is not a measure of NS itself. NS happens when the fecundity of females is differentially distributed across a population. Thus, when some females become more fecund than others their population undergoes natural selection. The study cited by Nosy does not address differential fecundity, which is tantamount to NS.

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”HM

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Please tell me you aren't saying that fecundity is unrelated to natural selection.If GirlA has twice as many children as GirlB, she's spreading her genes more effectively.

Well, yes, it is related. But fecundity is not precisely the issue here; it's the distribution of fecundity in a population ” its differential distribution ”that is what NS is all about. Again, NS is defined as 'differential reproductive success amongst individuals across a population.' Fecundity is only a measure of production, not a measure differential production.”HM

What interests me most is that way off in the fruit-fly genomes a kind of fruit-fly homosexuality occurs, and obviously without the flies getting to choose their own sexual orientation. In a queer way, this stuff is beginning to sink in. We need to learn more about this homo mechanism.”HM