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Can somone who fully understand the science of evolution explain THIS- Watch

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    IE on the basis that evolution and also principle of 'survival of fittest' means that various 'random' genetic mutations /variations survive throughout generations due to them having some benefit of survival, or in humans are more attractive in the mating process somehow - how does this apply to gay people.

    this is making the assumption that people are 'born' gay by 'developing some genetic attribute' - how is this attribute passed down through mating of human species so that gay people are a regualr occurance throughout generations
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    Say if it were a gay gene, from what I understand, you can have certain alleles which need two copies for the trait to show up, if you only have one copy then it won't show up so you would not be gay, so someone could be a carrier of the allele (meaning they can pass it on to their children) but not have it represented in themselves (so would not be gay). If both the parents have a single copy of the allele, there is a 1 in 4 chance of the child being gay. Also random mutations still occur, so the allele could randomly happen.
    I'm not sure if this is correct though.
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    (Original post by LoveMarshmellows)
    Say if it were a gay gene, from what I understand, you can have certain alleles which need two copies for the trait to show up, if you only have one copy then it won't show up so you would not be gay, so someone could be a carrier of the allele (meaning they can pass it on to their children) but not have it represented in themselves (so would not be gay). If both the parents have a single copy of the allele, there is a 1 in 4 chance of the child being gay. Also random mutations still occur, so the allele could randomly happen.
    I'm not sure if this is correct though.
    ok but then these i would assume be random occourances of evolutionery genetic change, how do they remain prominent in human genrations if they do not provide any evolutionery benefit - in fact if a person inherits 'gay ' behaviours, he /she is unlikely to reproduce and pass those on
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    (Original post by Meenglishnogood)
    ok but then these i would assume be random occourances of evolutionery genetic change, how do they remain prominent in human genrations if they do not provide any evolutionery benefit - in fact if a person inherits 'gay ' behaviours, he /she is unlikely to reproduce and pass those on
    In the same way that other non beneficial genes stay in the population such as cystic fibrosis and huntington's disease which are both genetic but not all that uncommon.
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    (Original post by Meenglishnogood)
    ok but then these i would assume be random occourances of evolutionery genetic change, how do they remain prominent in human genrations if they do not provide any evolutionery benefit - in fact if a person inherits 'gay ' behaviours, he /she is unlikely to reproduce and pass those on
    We have quite a few alleles which have no evolutionary benefit to us, it takes a while for a gene to disappear and as more and more people are surviving and gay people having had children in the past (due to having to suppress their true sexuality) I would assume that there would be a higher chance of people being carries, it is no longer about survival of the fittest.
    Although things like this do puzzle me!
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    You've answered your own question - it is random. There is no rule that only beneficial alleles propogate.
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    (Original post by LoveMarshmellows)
    We have quite a few alleles which have no evolutionary benefit to us, it takes a while for a gene to disappear and as more and more people are surviving and gay people having had children in the past (due to having to suppress their true sexuality) I would assume that there would be a higher chance of people being carries, it is no longer about survival of the fittest.
    Although things like this do puzzle me!
    (Original post by SophieSmall)
    In the same way that other non beneficial genes stay in the population such as cystic fibrosis and huntington's disease which are both genetic but not all that uncommon.
    yeh i guess all of that is the case, i jsut found it odd that if these were random genetic occourances ( and not passed down via natural selection or mating benefit) that they were still fairly common for a random gene( something like 10-15% its estimated o f popultion)
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    (Original post by Meenglishnogood)
    yeh i guess all of that is the case, i jsut found it odd that if these were random genetic occourances ( and not passed down via natural selection or mating benefit) that they were still fairly common for a random gene( something like 10-15% its estimated o f popultion)
    In terms of homosexuality, there are numerous reasons why someone can be so, and it is highly unlikely it is all down to the same genes. Like with many traits, it is quite possible that genes assosciated with homosexuality provide other effects in other situations.

    The other point is that genesare not so much bred due to succes, but bred out due to failure. Even if we were to assume that there was a gene that just made someone homosexual, it would not prevent them from reproducing, but would most likely just reduce the likelihood of them reproducing, which would mean it would be continued to pass down (likely only through one parent) and remain present, but reduced.
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    (Original post by Meenglishnogood)
    IE on the basis that evolution and also principle of 'survival of fittest' means that various 'random' genetic mutations /variations survive throughout generations due to them having some benefit of survival, or in humans are more attractive in the mating process somehow - how does this apply to gay people.

    this is making the assumption that people are 'born' gay by 'developing some genetic attribute' - how is this attribute passed down through mating of human species so that gay people are a regualr occurance throughout generations
    We don't actually know what causes homosexuality, it might be genetic, due to environmental factors (such as exposure to hormones in the womb) or a combination of both. One particular hypothesis is that a gene that causes an increase in libido in females may increase the likelihood of homosexuality in males, though obviously this is just a hypothesis as yet.
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    (Original post by Comus)
    We don't actually know what causes homosexuality, it might be genetic, due to environmental factors (such as exposure to hormones in the womb) or a combination of both. One particular hypothesis is that a gene that causes an increase in libido in females may increase the likelihood of homosexuality in males, though obviously this is just a hypothesis as yet.
    is this the libido of a woman that will give birth to that male?
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    I don't claim to fully understand evolution, but I'll give it a shot anyways .

    It's a very good question, and it's one where there is not really a consensus, yet.

    One of the dominant hypothesis is that the opposite-sexed siblings of homosexuals are typically more attractive, so they compensate for the "unfitness" of the homosexual siblings. For example, sisters of gay men tend to be more attractive, so they are evolutionarily more successful, and so homosexual genes get passed on that way.

    There are quite a few evolutionary "oddities" like this one.

    For example, most serious mental illnesses (schizophrenia, autistic spectrum disorder, depression, bipolar disorder, anorexia nervosa) are very highly genetic, and they clearly reduce the fitness of individuals suffering them. Why then, has evolution not taken them out? There also doesn't seem to be a decreasing trend of incidences for those illnesses either - the percentage of population that suffer from schizophrenia, for example, has stayed more or less the same throughout history. One would expect such serious genetic illnesses to be wiped out by evolution after just a few generations, but that's clearly not the case.

    Do those genes offer some benefit? What kind of benefits?

    For some it's more apparent than others - for example, psychopathy still exists because psychopaths actually tend to do well in society. Psychopathy (basically extreme selfishness) is actually very good for individual survival, at the cost of the society.

    For things like eating disorders (contrarily to popular belief, it's not, at least not entirely, a modern social construct), it can conceivably be a mean to control fertility. When the environment is bad (lack of food, etc), it could be more adaptive for females to invest more in siblings, then making their own children. After all, their siblings carry most of the same genes as themselves. This is very common in birds for example.

    Mood disorders (depression/mania/bipolar) can be a mean to control effort.

    At times with good opportunities, it makes sense to expand more effort to take advantage of the situation, and at times with no opportunities, it makes sense to reduce effort and conserve energy.

    Depression helps people disengage from unobtainable goals (which would be maladaptive to pursue).

    It has also been hypothesized that depression is used as an appeasement strategy, to reduce chance of attack by stronger intra-sex competitors.

    That's the subject of an elective course I took in uni, and I really enjoyed it.

    It's a very complex issue and there is still no consensus in many cases.
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    (Original post by SophieSmall)
    In the same way that other non beneficial genes stay in the population such as cystic fibrosis and huntington's disease which are both genetic but not all that uncommon.
    But they're not diseases that would stop you reproducing, and hunting tons especially is not one that is going to have any affect at all in your reproductive chances as it occurs fairly late in life.

    But to answer your question more accurately, nobody understands evolution fully that's why we research it still, and that is probably why you are getting unsatisfactory answers.
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    For most of human history, gay people probably had as many kids as straight people. Either through a 'gay for pleasure, straight for kids' type arrangement (ancient Greeks) or suppressing their true sexuality to 'fit in' to societies which didn't accept homophobia.
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    (Original post by limetang)
    But they're not diseases that would stop you reproducing, and hunting tons especially is not one that is going to have any affect at all in your reproductive chances as it occurs fairly late in life.

    But to answer your question more accurately, nobody understands evolution fully that's why we research it still, and that is probably why you are getting unsatisfactory answers.
    Aye but as many people have already pointed out gay people have still been having kids for many years because they would not show their real sexuality. And now that gay people can get surrogates and have children that way nowadays they will still reproduce.
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    There is the propagation of random genes, for which there are surely a multitude which are responsible. I'm assuming that homosexuality has to do with genes coding for hormones and neurotransmitters as well as cerebral structuring (as there are sex differences in cortical physiology and anatomy). Then there is always the fact that genes interact with the environment. There are also societal pressures and psycho-dynamics to take into consideration.
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    (Original post by Meenglishnogood)
    is this the libido of a woman that will give birth to that male?
    Sorry the above wasn't very clear, I'll rephrase it:

    One particular hypothesis, is that there may be a gene which increases sex drive when present in females (and so are more likely to have offspring that also possess this gene), but increases the likelihood of homosexuality in males.

    There are some problems with this hypothesis however, for a start it doesn't account for lesbians and we've no idea whether such a gene (or allele) would be dominant or recessive.

    As such, we don't know what causes homosexuality and though it would be interesting to know, I don't think it really matters.
 
 
 
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