Gene variants identified that may influence sexual orientation in men and boys

December 8, 2017 by Bob Yirka, Medical Xpress report

Credit: CC0 Public Domain
(Medical Xpress)—A large team of researchers from several institutions in the U.S. and one each from Australia and the U.K. has found two gene variants that appear to be more prevalent in gay men than straight men, adding further evidence of sexual orientation having a biological component. In their paper published in Scientific Reports, the group describes their study, which consisted of comparing the genomes of multiple gay men against multiple straight men.

The results by the group represent the first identification of specific as perhaps influencing in males. The finding was made as part of a study of DNA samples from 1231 straight men and 1077 gay men. The team reports that they did not focus exclusively on any one part of the genome, instead scanning the entire genome looking for differences in single letters rather than whole , as has been done in the past. Doing so, the team further reports, allowed them to identity two gene variants that seemed to be linked to sexual orientation.

One of the genes is located on chromosome 13, which prior research has shown has an impact on the diencephalon, a part of the hypothalamus —a part of the brain shown to be differently sized between gay and straight men. The other gene was found on chromosome 14, which prior research has shown is mainly involved with the thyroid, though it does also have an impact on the brain via a protein involved in stimulating the thyroid. Some prior studies have led to findings that suggest the might also be involved in sexual orientation.

The findings by the team do not settle the argument of whether homosexuality in people is biology-based, but instead offers more that suggests it is likely the case. Prior studies that looked at family histories have also offered some evidence of biology playing a role while other studies have found some differences in chromosomes. In this study, the number of samples tested was too small to offer conclusive evidence—larger studies will have to be undertaken to solidify the evidence.

Explore further: Study suggests genetic link for male homosexuality (Update)

More information: Genome-Wide Association Study of Male Sexual Orientation, Scientific Reports (2017). DOI: 10.1038/s41598-017-15736-4

Abstract
Family and twin studies suggest that genes play a role in male sexual orientation. We conducted a genome-wide association study (GWAS) of male sexual orientation on a primarily European ancestry sample of 1,077 homosexual men and 1,231 heterosexual men using Affymetrix single nucleotide polymorphism (SNP) arrays. We identified several SNPs with p < 10−5, including regions of multiple supporting SNPs on chromosomes 13 (minimum p = 7.5 × 10−7) and 14 (p = 4.7 × 10−7). The genes nearest to these peaks have functions plausibly relevant to the development of sexual orientation. On chromosome 13, SLITRK6 is a neurodevelopmental gene mostly expressed in the diencephalon, which contains a region previously reported as differing in size in men by sexual orientation. On chromosome 14, TSHR genetic variants in intron 1 could conceivably help explain past findings relating familial atypical thyroid function and male homosexuality. Furthermore, skewed X chromosome inactivation has been found in the thyroid condition, Graves' disease, as well as in mothers of homosexual men. On pericentromeric chromosome 8 within our previously reported linkage peak, we found support (p = 4.1 × 10−3) for a SNP association previously reported (rs77013977, p = 7.1 × 10−8), with the combined analysis yielding p = 6.7 × 10−9, i.e., a genome-wide significant association.

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11 comments

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julianpenrod
1.4 / 5 (9) Dec 08, 2017
An attempt at "validating" the claim that people are born homosexual, that it isn't a choice.
Among other things, note that homosexuality involves a suite of behaviors and attitudes. Depression that lasts for a year or more; contempt for women; an inability to be faithful, in any extent, to a single partner; self loathing larger than in any other group; severe anxiety disorders; fatalistic sentiments; massive drug use;an inability to control onesself to keep from engaging in practices they find loathsome and disgusting; compulsive, uncontrolled indulgence in mindless promiscuity; rates of suicide higher than any other group. Ar the variants responsible for all that?
And, note, people can be born with many things, from recklessness to an inability to control their temper. That doesn't mean those are right.
ShotmanMaslo
4.3 / 5 (6) Dec 08, 2017
Homosexuality may be genetic or it may not be. But it is not a choice either way.
TrollBane
4.2 / 5 (5) Dec 08, 2017
JP once again displays his contempt for the concept of statements backed by evidence.
Shakescene21
5 / 5 (2) Dec 08, 2017
This type of study is "statistical fishing" that doesn't prove anything unless the experiment can be repeated with a different sample and yield the same outcomes. This study did a genome-wide comparison of individual DNA base pairs, and since the human genome contains 3.2 billion base pairs, it is inevitable that with this many comparisons there will be some "statistical flukes" that falsely show correlations. The correct scientific approach is to repeat the experiment with a different group of men and then see if the first study's correlations are repeated in the second study.
TheGhostofOtto1923
5 / 5 (1) Dec 08, 2017
Of course it's biology based.

Many species have evolved ways of coping with overpopulation. Rabbits will begin absorbing fetuses in overcrowded warrens. Firstborns will shove unmatched eggs out of overcrowded nests. Many examples of infanticide among animals, as well as homosexuality.

So we should fully expect to find such growth-limiting traits in humans as well. A higher incidence of gaydom among younger brothers may indicate a mothers epigenetic efforts to limit competition for her firstborn who has the best chance of surviving to reproduce in an overcrowded group.

Many questions come to mind;
•Are gays born more often in cities?
•Are fewer gays born in subgroups with strong tribal identities such as religious communities?
•Can joining one such subgroup actually cause a homosexual to revert?
•Are fewer gays born in colonies and pioneer societies?
•Does incarceration in overcrowded facilities affect expression of these genes?
TheGhostofOtto1923
5 / 5 (1) Dec 08, 2017
We can also look at other attributes such as eating disorders, addiction, and delayed emotional maturity in youngsters as evolved growth-limiting traits.

Throughout history and in many cultures today adolescence doesnt exist. People normally begin reproducing at puberty because as weak tropical animals with high attrition rates, we needed to compensate.

But perhaps the state of adolescence or extended immaturity is also a biological response to overpopulation, as well as the reinforcing behaviors of parents wishing to keep their kids from reproducing for as long as possible.

And we can look to the animal world for similar behaviors as evidence that these traits are indeed biological.
TheGhostofOtto1923
not rated yet Dec 08, 2017
It's not only overgrowth that is a problem. Male competition for repro rights can destabilize tribal cohesion. Tribes whose men were more willing to trust one another and sacrifice themselves in battle, could be expected to prevail.

"The Sacred Band of Thebes (Ancient Greek: Ἱερὸς Λόχος, Hieròs Lókhos) was a troop of select soldiers, consisting of 150 pairs of male lovers which formed the elite force of the Theban army in the 4th century BC."

-Greece is a mountainous country with limited arable land. Greek culture had many ways of limiting growth including ritual wars among city-states.

Spartan males for instance werent allowed to wed until age 25, after they had proven themselves in battle (read - survived).
Osiris1
1 / 5 (3) Dec 09, 2017
Now we get a new way to eliminate all gays from society........ abortion of fetuses with this 'nonpreferred' gene. Short jump from here to Hitler's genocides, eh?
unrealone1
1 / 5 (3) Dec 09, 2017
Is there a vaccine statistical correlation?
The average African male has Two wives and Six children.
The Average American is?
unrealone1
1 / 5 (1) Dec 09, 2017
http://www.dailym...ove.html
May be?
Scientists-developed-gay-bomb-make-enemy-soldiers-stop-fighting-make-love
TheGhostofOtto1923
not rated yet Dec 09, 2017
Now we get a new way to eliminate all gays from society........ abortion of fetuses with this 'nonpreferred' gene. Short jump from here to Hitler's genocides, eh?
Gaydom is being promoted whereas only a few gens ago it was a felony. Cite poor oscar wilde vs sir elton john.

How come? Gaydom reduces growth. The impetus is to reduce growth AT ALL COSTS.

Male sperm count is already way down. Sexual harassment claims for offhand comments. Trump kissed a journalist - impeach him!

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