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The largest study to date on the genetic basis of sexuality (2019)

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Re: The largest study to date on the genetic basis of sexuality (2019)

#111

Is there any trait that is strongly linked to a single gene? Whenever I hear a news article that there is no X gene, I am completely unsurprised. The idea that a single gene would uniquely determine a particular trait, as if it were a variable in a program like "bool has_blue_eyes", seems oversimplified and unrealistic.

> Is there any trait that is strongly linked to a single gene?

Sure.

Sickle-cell anaemia is one classic case, one (recessive) gene.

Huntington's disease is another, it's about a specific repeat number.

But, as you say, most complex traits (such as height) aren't like that, and involve hundreds or thousands of different genes. IIRC eye color is actually fairly simple, not one gene but much of the control in just a handful? Maybe hair color too? (But not super-sure.)

Re: The largest study to date on the genetic basis of sexuality (2019)

#112

Earlier quoted context omitted.

The trouble with that argument is that it also works with, "If there was a genetic cause for shortsightedness, why is it still around?" "If there was such a thing as a genetic disease, why haven't they evolved out?" "If not having X-ray vision was genetic, wouldn't the absence of X-ray vision have been selected out?" You really can't expect evolution to accomplish its "goals," per se. It is sort of a gentle flow down…

Not really. Say I'm shortsighted, and still a potential mating partner due to a variety of other traits (being a billionaire, or looking suspiciously similar to Ryan Gosling). In that case, I would be able to transmit my genes to my eventual offspring. The case with gay genes is different. Regardless of any other trait, I'm genetically prone to not have any offspring. Thus, eventually my genes would be less and less…

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Re: The largest study to date on the genetic basis of sexuality (2019)

#113
I've always thought hormones had something to do with sexuality, because as Wikipedia says "sex hormones control the ability to engage in on the motivation to engage in sexual behaviors." What I'm thinking here is that motivation. Some people are motivated to engage with one gender or sexuality, and it becomes hard wired through that developmental process.

Re: The largest study to date on the genetic basis of sexuality (2019)

#114
post #51

Earlier quoted context omitted.

I would suggest asking yourself "what is being straight?", assuming that you identify as such.

I can certainly interpolate my personal experiences but I'm afraid I would miss something. Also, doing so would not explain this: Why some people dress or act similar to opposite sex to appear attractive to someone of the same sex? I mean, voice gestures etc. Hm...I should not said act, it's likely their trait. Anyway, why would someone who is gay be attracted to that person rather than opposite sex. I think sexualit…

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Re: The largest study to date on the genetic basis of sexuality (2019)

#115

Is there any trait that is strongly linked to a single gene? Whenever I hear a news article that there is no X gene, I am completely unsurprised. The idea that a single gene would uniquely determine a particular trait, as if it were a variable in a program like "bool has_blue_eyes", seems oversimplified and unrealistic.

ABO blood group gene

https://en.wikipedia.org/wiki/ABO_%28gene%29

Re: The largest study to date on the genetic basis of sexuality (2019)

#116

Is there any trait that is strongly linked to a single gene? Whenever I hear a news article that there is no X gene, I am completely unsurprised. The idea that a single gene would uniquely determine a particular trait, as if it were a variable in a program like "bool has_blue_eyes", seems oversimplified and unrealistic.

Yes. MC1R which people with red hair carry. It's a very strongly associated gene. Also "People with freckles and no red hair have an 85% chance of carrying the MC1R gene that is connected to red hair. People with no freckles and no red hair have an 18% chance of carrying the MC1R gene linked to red hair."

https://en.wikipedia.org/wiki/Melanocortin_1_receptor

Re: The largest study to date on the genetic basis of sexuality (2019)

#117

Honest question: what is being gay? Is it physical attraction? Emotional attraction? Both? Is it dislike, fear(?) of opposite sex?

Usually refers to romantic and/or sexual attraction to the same sex. > Is it dislike, fear(?) of opposite sex? Not generally, no, just like most straight people don't dislike members of their own sex.

I think a lot of straight people would, however, feel a degree of repulsion towards the idea of kissing and having sex with someone of the their non preferred-sex. A consideration which, due to culturally norms, is probably pushed into the heads of gay people.

Anecdotally I think most of my gay friends have commented on how gross vaginas are to them. Add whatever clarifications on fluidity and spectrums that you want....

Re: The largest study to date on the genetic basis of sexuality (2019)

#118

Genes aren’t a good way to explain most things. They’re more like LEGO blocks. It’s how the cells use and express the genes that matters. So you want to look at regulatory regions of the genome, promoters, and even how and when the dna folds up to inactive large regions. That’s where all the action is.

There are two meanings to "gene" here. What you describe as lego blocks are segments which code for a protein, which is one meaning.

The other is just any code which affects the phenotype, including promotors etc. The SNPs mentioned in TFA are just known fairly common single-point differences, but aren't necessarily in coding DNA. Of course these are still heritable, just like coding changes.

Re: The largest study to date on the genetic basis of sexuality (2019)

#120
post #2

Not an expert here but, IF a gay gene existed, wouldn't have it been evolved into extinction?

There are several possibilities.

1. If having gay relatives improved the chances that you will have children and they would survive to themselves reproduce, then evolution could favor maintaining a gay gene.

Remember that for nearly all of our species' existence, and that of the pre-humans we evolved from, we've lived most of our lives in arrangements where our close relatives lived near us and most people in the region were also related to us.

Your children have half your genes. Your siblings' children have a quarter of your genes. So in effect two of your siblings children are equivalent to one of your own as far as getting your genetic material into the next generation goes.

If being gay meant that your sibling does not have their own kids to take care of and so they devote effort that would have gone to raising their own kids to helping their straight siblings' with their kids or to doing things that help the village that those with kids don't have the time for, that might greatly increase the survival rate of those kids enough to make up for not having kids of their own.

2. Being gay doesn't mean you can't have kids. Throughout most of our history, many many people have had kids with people they have not been attracted to. That goes for both gay people and straight people.

3. What if it were a bisexual gene rather than a gay gene? Having people in your tribe that can form with both men and women the kind of close bonds the people form for the sexual partners has some obvious advantages.

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