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Is There a 'Gay Gene'?
Posted: Thu Feb 03, 2005 12:33 pm
New Genetic Regions Associated With Male Sexual Orientation Found
By Jennifer Warner
WebMD Medical News
Reviewed By Michael Smith, MD
on Friday, January 28, 2005
Jan. 28, 2005 - The genes a man gets from his mother and father may play an important role in determining whether he is gay or not, according to a new study likely to reignite the "gay gene" debate.
Researchers say it's the first time the entire human genetic makeup has been scanned in search of possible genetic determinants of male sexual orientation. The results suggest that several genetic regions may influence homosexuality.
"It builds on previous studies that have consistently found evidence of genetic influence on sexual orientation, but our study is the first to look at exactly where those genes are located," says researcher Brian Mustanski, PhD, a psychologist at the University of Illinois at Chicago.
Those previous studies looked only at the genes located on the X chromosome. Genes on this chromosome are only passed to a son from his mother. But this study examined genetic information on all chromosomes, including genes from the father.
The findings show that identical stretches of DNA on three chromosomes were shared by about 60% of gay brothers in the study compared to the about 50% normally expected by chance.
Gay Gene Debate
A heated debate over the existence of a "gay gene" emerged from a 1993 report published in the journal Science by then-NIH researcher Dean Hamer, PhD. That study linked DNA markers on the X chromosome to male sexual orientation.
Since then, questions arose regarding the validity of those results. Other researchers are attempting to replicate and verify Hamer's findings. Hamer is also senior author of the current study, which appears in the March issue of Human
But researchers say this study takes a different approach. Its goal was not to replicate those findings but to search for new genetic markers associated with male sexual orientation.
"Since sexual orientation is such a complex trait, we're never going to find any one gene that determines whether someone is gay or not," says Mustanski. "It's going to be a combination of various genes acting together as well as possibly interacting with environmental influences."
Previous studies in male twins have suggested that between 40%-60% of the variability in sexual orientation is due to genes. The rest is thought to be due to environment and possibly other biologic but nongenetic causes.
Search for Gay Genes.
Is There a 'Gay Gene'?
New Genetic Regions Associated With Male Sexual Orientation Found (Continued )
In the study, researchers analyzed the genetic makeup of 456 men from 146 families with two or more gay brothers.
The genetic scans showed a clustering of the same genetic pattern among the gay men on three chromosomes -- chromosomes 7, 8, and 10. These common genetic patterns were shared by 60% of the gay men in the study. This is slightly more than the 50% expected by chance alone.
The regions on chromosome 7 and 8 were associated with male sexual orientation regardless of whether the man got them from his mother or father. The regions on chromosome 10 were only associated with male sexual orientation if they were inherited from the mother.
Mustanski compares the study's approach to a search for doctors in a town of 40,000 people, a number that roughly corresponds to the number of human genes.
Rather than guessing that doctors live in a particular type of house and going to only the houses that meet that criteria, researchers in this scenario would knock on every door to ask the residents if a doctor lives on their street. Using a similar approach, researchers were able to locate a few potential genetic neighborhoods that likely contribute to male sexual orientation.
Researchers say the next step is to verify these results in a different group of men to see if the same genetic regions are associated with sexual orientation. If the findings hold up, then Mustanski says they could start to look for the individual genes within these regions linked to sexual orientation.
New Targets for Gay Gene Research
Elliot S. Gershon, MD, professor of psychiatry and human genetics at the University of Chicago, says the study represents an important step forward in understanding how genes affect human sexual orientation.
"It is worth testing genes within a region of linkage to see if one of them has a variant that is more frequent in men who are gay than in men who are not," says Gershon, who is also currently involved in another study of gay brothers and genetic influences on sexual orientation.
"This report adds to the legitimacy of research on normal variations in human behavior," Gershon tells WebMD. "There is an argument that has been made in public press that it doesn't make sense to study conditions or traits that are behavioral. But this suggests that there is a genetic contribution to this particular trait of same sex orientation."
SOURCES: Mustanski, B. Human Genetics, March 2005 online first edition. Brian Mustanski, PhD, department of psychiatry, University of Illinois at Chicago. Elliot S. Gershon, MD, professor of psychiatry and human genetics, University of Chicago. News release, University of Illinois at Chicago. Council for Responsible Genetics.
I posted this here. But, I wonder whether you have a religious perspective of it, or whether you have a particular opinion on this subject. In other words, do you think the scientists are wasting their time?
Re: Is There a 'Gay Gene'?
Posted: Thu Feb 03, 2005 4:10 pm
we can look at it from two angles:
*From a purely scientific standpoint, the following statement is not correct in my view:
The genes a man gets from his mother and father may play an important role in determining whether he is gay or not</B>...
It would be more appropriate to say that those so-called gay-genes play a role in determining the tendencies of some men toward homosexuality. Genes cannot make one gay, nor can they make one violent or good. In Genetics, what we see and observe is called a phenotype, which is a combination of the genotype (genetic makeup) of the individual and his/her/its environment (physical, social, economic, religious, cultural....). I would agree that they can possibly predispose</B> people towards homosexuality or any other lifestyle for that matter, if they effectively exist and their genetic role has been firmly established. In that regard, the predisposition towards a behavior or lifestyle is basically all our genes can confer to us.
*From a religious point of view (biblical christianity, I should say), once people accept the message and teachings of Jesus-Christ and thus become true believers, their lifestyle changes from whatever it may have been in the past. A good example:
Do you not know that the wicked will not inherit the kingdom of God? Do not be deceived: Neither the sexually immoral nor idolaters nor adulterers nor male prostitutes nor homosexual offenders nor thieves nor the greedy nor drunkards nor slanderers nor swindlers will inherit the kingdom of God. And that is what some of you were. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God (1 Corinthians 6:9-11).
According to the above text, people previously enganged in homosexual lifestyle (for whatever reason) are also listed among those whose life was changed by the message of Jesus-Christ. ANYBODY can change if they want to. I don't know if you agree with me...
Posted: Sat Feb 05, 2005 8:05 pm
My answer to this has always been:"M' bwè pwa!" That is the reason I asked you. In trying to come up with an answer, I always tried to extrapolate, if one wants to go beyond the religious condemnation. Like, when I was a teenager or in my early twenties, I could not imagine what it is a woman sees in a man that makes him attractive to her. From that, I always surmised there has to be something in our nature that makes some, heterosexual, and others, homosexual. That is what made the genes suspect to me. But, if your explanation of their work patterns is as exact as you describe it, I was looking in the wrong direction.
Also, extrapolating, I have seen in Nature stories that genetically we are inclined to enter into some activities in order to survive or procreate. Examples of them are: pleasure of eating to survive, and sexual pleasure to procreate. We all know that sometimes, in uncommon cases, errors occur in the genes and they behave in a totally opposite way. Within your understanding of how they work, is it possible that errors in the genetic make-up, in some cases, may make some inclined to adopt homosexuality. In those cases, is it reasonable to believe that they will not strive in an heterosexual relationship? If they won't, should we see them like we do thieves, who want something they don't have but cannot control their impulse of going without? Or, instead, like they can't help it? Any more thoughts on this?
Posted: Mon Feb 07, 2005 5:24 pm
I don't have the answers to your questions, but we can continue to share our ideas...
...From that, I always surmised there has to be something in our nature that makes some, heterosexual, and others, homosexual. That is what made the genes suspect to me. But, if your explanation of their work patterns is as exact as you describe it, I was looking in the wrong direction.
This subject is complicated because beyond the genetics of humans there is also the element of choice or will, if you will. Yes our nature dictates our preferences, but from what I understand, we still make choices. Let me put it another way, our environment helps us make our choices according to our own nature or against that very nature.
...We all know that sometimes, in uncommon cases, errors occur in the genes and they behave in a totally opposite way. Within your understanding of how they work, is it possible that errors in the genetic make-up, in some cases, may make some inclined to adopt homosexuality.
I would say that - if the genetic effect of the so-called gay genes is firmly established - it would then be possible for the genetic make-up of some men to predispose them towards homosexuality, the same way that the genetic make-up of others would predispose them towards alcoholism or any other behavior of this type. Just the predisposition. The term 'genetic error' can mean a lot of things here...
In those cases, is it reasonable to believe that they will not strive in an heterosexual relationship? If they won't, should we see them like we do thieves, who want something they don't have but cannot control their impulse of going without? Or, instead, like they can't help it? Any more thoughts on this?
It's difficult for me to be clear and specific here. But, I remember seating with a friend of mine in the living room of an ex-gay who decided it was time for him to live a natural life - homosexuality beind understood as against nature. Well, this guy stopped being gay and changed his life around.
There are plenty of heterosexuals who cannot live happilly in their heterosexual life. There are also scores of unhappy homosexuals. It takes more than sex to make one happy. The thing is complicated but genetics has not offered the scientific "it's not my fault" that so many need. I heard a young gay say once that being gay is not about sex.......funny!
Posted: Tue Apr 11, 2006 9:17 am
I heard a young gay say once that being gay is not about sex.......funny!
Well, it is not that funny. One may well be heterosexual or gay, without ever engaging in sex!