Is homosexuality genetic?

My understanding is that things can be biological without being genetic. Handedness, for instance.

And it seems extremely doubtful that human sexuality is genetical determined. We'd see more clear links if that were the case. It's more likely gentically influenced like any number of other personality traits.
 
Ace_of_Sevens said:
My understanding is that things can be biological without being genetic. Handedness, for instance.
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There are suggestions that birth order plays a role in handedness in chimps (Hopkins & Dahl, 2001). Even within the context of these suggestions, Hopkins and Dahl found that "the genetics of their [the chimps'] handedness is very strong." Since they found about 30% left-handed chimps and since human lefties are far fewer they hypothesize that there is more cultural mediation in human handedness. This work, whose title I can't put my hands on (sorry) was published in Psychological Science Vol 12, No. 4.

Cheers,
 
Titananarchy said:


Nothing wrong with high standards for evidence, but bear in mind that direct evidence in humans is (for ethical reasons) more circumstantial, but nonetheless compelling.

Please also note that I do not make the case that homosexuality causes changes in hypothalmus size, only that both sexual orientation and hypothalmus size have a common (biological) cause.
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1. "Circumstantial but compelling" - I am saying there really isn't such a thing in science. Could be coincidence. Ethical reasons do not enter into the equation when determining proof.

2. "both ... have a common (biological) cause" - that means - BY DEFINITION - that the relationship is spurious. If there were such an underlying common cause, you would need to identify it and measure it. Despite the apparent reasonableness of the results, they will not be valid. Period.
 
The role of genetics in determining the functioning of an organism is one of the most abstract of all biological systems. The 'cause - effect' relationship is impossible to unravel.

What I tell my students is this - genes are like the blueprints for making a vehicle. A car can go fast, or slow, have massive torque or all the grunt of a squirrel. Over time, things happen to the car to change its performance. Ultimately a driver's free will will determine how fast the car goes based on circumstances such as weather, need for speed etc.

So Hitler was not a dictator genetically, nor an arsehole. He had the basic mechanisms there for leadership based on the essential emotions.

Is homosexuality genetic? The basic biochemical tools required are. But they are merely influential - a straight person may have the exact same molecular machinary but act differently.

It's looking more and more like a true chaos theory at work.

Athon
 
athon said:
What I tell my students is this - genes are like the blueprints for making a vehicle.
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This sounds wrong, athon.

Blueprints are exactly what genes are not.
The blueprint for a vehicle tells you exactly how the vehicle should turn out

What about recipe?
A recipe is nearly always pretty vague. A pinch of this. A dash of that. Add some of this and a handful of that......

"Genes are like recipes for making cakes."

How does that sound?
 
Blueprints are exactly what genes are not.
The blueprint for a vehicle tells you exactly how the vehicle should turn out.

What about recipe?
A recipe is nearly always pretty vague. A pinch of this. A dash of that. Add some of this and a handful of that......

"Genes are like recipes for making cakes."
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A recipe generally has two types of information; a list of ingredients, and some instructions for putting them together. It's easy to see a gene as a list of ingredients, but where are the instructions for putting them together?
 
Dymanic said:


A recipe generally has two types of information; a list of ingredients, and some instructions for putting them together. It's easy to see a gene as a list of ingredients, but where are the instructions for putting them together?
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Since things do (usually) get put together correctly ( i.e.. one eye on each side of the nose etc..), can't we assume the instructions are there? Even if we haven't learned how to read them yet.
 
Ace_of_Sevens said:
My understanding is that things can be biological without being genetic. Handedness, for instance.

And it seems extremely doubtful that human sexuality is genetical determined. We'd see more clear links if that were the case. It's more likely gentically influenced like any number of other personality traits.
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Handedness and cilia
 
Originally posted by Diogenes

Since things do (usually) get put together correctly ( i.e.. one eye on each side of the nose etc..), can't we assume the instructions are there? Even if we haven't learned how to read them yet.
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Since we haven't learned how to read the instructions, how can we know how much flexibility in the assembly process is tolerable, or to what extent it may be influenced by external factors?
 
Dymanic said:

Since we haven't learned how to read the instructions, how can we know how much flexibility in the assembly process is tolerable, or to what extent it may be influenced by external factors?
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We cant.. Yet..

And your observation is quite valid.

It is apparent that gene damage can result in improper assembly.. Thalidomide, comes to mind..

However, it is also apparent that certain degrees of damage can be repaired. It would seem to be comparable to ' error-checking-and correction' as it applies to computer memory, where the original code can be reconstructed, based on a series of check bits.
 
Thalidomide's effect is not a result of genetic damage. Thalidomide suppresses functional pathways of proteins involved in formation of new blood vessels, the downstream effect of which is malformation.

However, your point, that damaged genes can lead to errors in assembly, stands.
 
Diogenes said:
However, it is also apparent that certain degrees of damage can be repaired. It would seem to be comparable to ' error-checking-and correction' as it applies to computer memory, where the original code can be reconstructed, based on a series of check bits.
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Interestingly, you're pretty close with the ECC analogy. The code is both redundant and degenerate. Recent research has suggested that the redundancies, in many cases, correspond with the most common transcription (copying) errors. In addition, there are built-in mechanisms to correct translation errors. Its a bit of a hodge-podge, but the various mechanisms serve together in error-checking and -correcting.

Cheers,
 
I have been reading this thread and waiting to comment. Let me just say this, show me proof homosexuality is genetic and I'll believe you. To be honest though, I could care less what makes someone gay. I have a friend Bryan who is gay and the root of his gayness has never come into question nor have I deemed it to affect our friendship in any way.


The only thing I am remotely curious about is just why Tom Cruise is gay. Genetics, Choice, or Scientology?
 
spoonhandler said:
Thalidomide's effect is not a result of genetic damage. Thalidomide suppresses functional pathways of proteins involved in formation of new blood vessels, the downstream effect of which is malformation.
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spoonhandler,

If you're talking about the suppression of Fibroblast Growth Factor (FGF), its less closely directed to blood vessels than this post implies. FGF clearly mediates vascularization, but it more proximal effect here seems to be a general distalizing signal. With thalidomide, the FGF signals that say "hey, you cells here need to turn into fingers (or toes) now" doesn't get properly suppressed. So limb buds too early start to form hands and fingers or feet and toes. The net effect of this early distalizing signal is foreshortened, malformed limbs. Although I note the jury is still out on exact mechanisms.

Cheers,
 
corplinx said:


The only thing I am remotely curious about is just why Tom Cruise is gay. Genetics, Choice, or Scientology?
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Beause he's just too damn cute to be straight! :D
 
Bill and AP, you do realize that Titananarchy is Titanpoint from back a few months, don't you?

I think there were lots of times he acted like a troll (hey, I think there are lots of times I act like a troll :D) but in general, I think he backed up his claims if dealt with in a civil manner.

Just give him the time and I think he'll come through with the goods.

Obviously I'm not speaking to the quality of the goods ;) But I don't think he's just running you around the yard for a giggle.

Sheesh, what am I doing here defending TP? :D

Adam
 
slimshady2357 said:
Bill and AP, you do realize that Titananarchy is Titanpoint from back a few months, don't you?
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Yes, but do I care? If it looks like a troll and it quacks like a troll, I'm going to treat it like a troll.

Do you understand that Bill and I are both biologists and that if there were a clear and accepted answer to the question of the origin of homosexuality, we probably would have heard about it?
 
Diogenes said:

We cant.. Yet..

And your observation is quite valid.

It is apparent that gene damage can result in improper assembly.. Thalidomide, comes to mind..

However, it is also apparent that certain degrees of damage can be repaired. It would seem to be comparable to ' error-checking-and correction' as it applies to computer memory, where the original code can be reconstructed, based on a series of check bits.
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Um, I was under the impression that Thalidomide caused an unbalance of hormone/precursor/something that, when present at the wrong time, messed up limb formation.

I wasn't aware that it was "gene damage", in fact if I recall correctly, it's not, it causes a failure in the development process instead.

(edited to say never mind, somebody already got there, somebody who is much closer to the subject)
 
jj said:

Um, I was under the impression that Thalidomide caused an unbalance of hormone/precursor/something that, when present at the wrong time, messed up limb formation.

I wasn't aware that it was "gene damage", in fact if I recall correctly, it's not, it causes a failure in the development process instead.
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Yes, Thalidomide-induced birth defects are developmental. They may occur if a pregnant mother takes the drug in her first trimester. http://www.thalidomide.ca/english/brochure2.htm The drug is safe for adults.

He chose a bad example.
 
arcticpenguin said:

Yes, but do I care? If it looks like a troll and it quacks like a troll, I'm going to treat it like a troll.

Do you understand that Bill and I are both biologists and that if there were a clear and accepted answer to the question of the origin of homosexuality, we probably would have heard about it?
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Yes, I was aware of both of your expertise in this area.

But do you really think he's going to come back with nothing, or something completely laughable?

I'm interested in what he's going to come back with (man, where is this faith coming from?). I can wait.

Adam
 
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