What do the new ‘gay gen’ tell about sexual orientatn? | New Scientist

Contents:

• THERE IS NO ‘GAY GENE.’ THERE IS NO ‘STRAIGHT GENE.’ SEXUALY IS JT PLEX, STUDY NFIRMS
• WHAT DO THE NEW ‘GAY GEN’ TELL ABOUT SEXUAL ORIENTATN?
• NEW STUDY FDS GEICS INFLUENCE LGBTQ SEXUALY, BUT STILL NO 'GAY GENE'
• WHY ARE PEOPLE GAY? GAY BY CHOICE OR IS BEG GAY GEIC?
• THERE’S (STILL) NO GAY GENE
• SEARCH FOR 'GAY GEN' COM UP SHORT IN LARGE NEW STUDY
• SCIENTISTS FD DNA DIFFERENC BETWEEN GAY MEN AND THEIR STRAIGHT TW BROTHERS
• GAY GEICS
• THERE’S NO ONE ‘GAY GENE,’ BUT GEICS ARE LKED TO SAME-SEX BEHAVR, NEW STUDY SAYS
• THE LIFE OF THE GAY GENE: OM HYPOTHETIL GEIC MARKER TO SOCIAL REALY
• MOM'S GEICS COULD PRODUCE GAY SONS
• NO ‘GAY GENE’: MASSIVE STUDY HOM ON GEIC BASIS OF HUMAN SEXUALY
• MANY GEN INFLUENCE SAME-SEX SEXUALY, NOT A SGLE ‘GAY GENE’
• HOW OUR GEN ULD MAKE GAY OR STRAIGHT
• IS THERE A "GAY GENE"? MAJOR NEW STUDY SAYS NO

THERE IS NO ‘GAY GENE.’ THERE IS NO ‘STRAIGHT GENE.’ SEXUALY IS JT PLEX, STUDY NFIRMS

However, blogists have documented homosexual behavr more than 450 speci, argug that same-sex behavr is not an unnatural choice, and may fact play a val role wh populatns. So-lled genome-wi associatn studi intified a gene lled SLITRK6, which is active a bra regn lled the diencephalon that differs size between people who are homosexual or heterosexual. While there is no sgle “gay gene, ” there is overwhelmg evince of a blogil basis for sexual orientatn that is programmed to the bra before birth based on a mix of geics and prenatal ndns, none of which the fet choos.

Humans have tried to unrstand human sexualy for centuri — and geics rearchers joed the ay the early 1990s after a seri of studi on tws suggted homosexualy ran fai. “As a teenager tryg to unrstand myself and unrstand my sexualy, I looked at the ter for “the gay gene” and obvly me across Xq28, ” said Fah Sathirapongsasuti, a study -thor and senr scientist at 23andMe, which he joked once led him to believe he hered his gayns om his mother. The rearchers had members of the same-sex muny review the study’s sign and language, and they adm that their termology and fns for gay, lbian and heterosexual do not reflect the full nature of the sexualy ntuum.

WHAT DO THE NEW ‘GAY GEN’ TELL ABOUT SEXUAL ORIENTATN?

“[Our study] unrsr an important role for the environment shapg human sexual behavr and perhaps most importantly there is no sgle gay gene but rather the ntributn of many small geic effects sttered across the genome, ” Neale said. In 1993, geic variatns a regn on the X chromosome men were lked to whether they were heterosexual or homosexual, and 1995, a regn on chromosome 8 was intified. Grave’s disease is more mon gay than straight men, and some rearch suggts that gay men tend to be thner – which might possibly be a rult of thyroid overdrive.

The latt fdgs open the prospect to intifyg the whole pathway of gen volved both homosexual and heterosexual orientatn, says Dean Hamer at the US Natnal Instut of Health, who led the study that ppoted chromosome X back 1993. CHICAGO (AP) The largt study of s kd found new evince that gen ntribute to same-sex sexual behavr, but echo rearch that says there are no specific gen that make people gay.

”Former Natnal Instut of Health geicist Dean Hamer said the study nfirms “that sexualy is plex and there are a lot of gen volved, ” but isn’t really about gay people. Those who nsir beg gay a disadvantage life (which still is, certa societi), might regard gay people differently if they knew that beg gay was an hered tra, rather than a nsequence of life events, such as a particular type of upbrgg, or mixg wh certa sorts of iends or even a liberate cisn.

NEW STUDY FDS GEICS INFLUENCE LGBTQ SEXUALY, BUT STILL NO 'GAY GENE'

An early study claimed that if one pair of (male) intil tws (who have intil geic patterns) was gay, there was a 100 percent chance of the other one also beg gay. It was quickly shown that, fact, the real chance of two intil tws beg gay was around 40-50 percent, whereas was ls non-intil on, though still somewhat greater than the general populatn. It very much appears that same-sex sexual attractn is not a choice but actg on is; so if you fe gay as the mere prence of same-sex attractn, then om everythg we unrstand, beg gay is not a choice.

If, on the other hand, you nsir someone to be gay only if they act on their same-sex attractn then beg gay n be nsired a choice pendg on an dividual's behavr. “We know that smell has a strong tie to sexual attractn, but s lks to sexual behavrs are not clear, ” said -thor Andrea Ganna, an stctor at HMS and Massachetts General Hospal om the Instute for Molecular Medice study is part a rponse to gay, lbian, and bisexual people’s cursy about themselv, said Fah Sathirapongsasuti, a senr scientist at 23andMe and -thor on the study, who is himself gay.

Michael Bronski, profsor of the practice media and activism wh the mtee on studi of women, genr, and sexualy, and thor of A Queer History of the Uned Stat, says the allure of a “gay gene” grew om the flourishg gay-rights movement the after the Stonewall rts 1969.

WHY ARE PEOPLE GAY? GAY BY CHOICE OR IS BEG GAY GEIC?

Conservative opponents of the movement claimed that “homosexual acts are a choice, people choose to m them, or people are sced to the gay liftyle, ” he explas.

THERE’S (STILL) NO GAY GENE

’77, then a rearcher at the Natnal Instut of Health, published rults showg a rrelatn between male homosexual behavr and a clter of gen, lled Xq28, at the tip of the X chromosome. Exactly which gene this clter may be volved has proven elive—the current study found no signifint associatn between the X chromosome and same-sex sexual behavr—but the ia that a “gay gene” might lie somewhere Xq28—or elsewhere—was ptivatg.

Zeke Stok, chief programs officer of the LGBTQ advocy anizatn GLAAD, ncurred an emailed statement: “This new study provis even more evince that beg gay or lbian is a natural part of human life, a ncln that has been drawn by rearchers and scientists time and aga.

Others have warned that the search for a geic e would pathologize homosexualy the same way psychology did the twentieth century: efforts by psychoanalysts such as Irvg Bieber led to the cln of homosexualy the Amerin Psychiatric Associatn’s Diagnostic and Statistil Manual of Mental Disorrs until 1972. As noted above, the gen that rrelated wh same-sex sexual behavr also rrelated wh willgns to take risks, a nnectn that might not hold up cultur where homosexualy is ls stigmatized and those who are ls risk tolerant would therefore feel more able to act openly.

SEARCH FOR 'GAY GEN' COM UP SHORT IN LARGE NEW STUDY

And bee the rearchers didn't fd gene variants that rrelated wh a gradient of sexual behavr, she says, unrcuts Aled Ksey's s-old sle, which ranked people on a spectm of sexualy, om exclively heterosexual to exclively homosexual.

Ngun reported that studyg the geic material of 47 pairs of intil male tws, he has intified “epigeic marks” ne areas of the human genome that are strongly lked to male dividuals, said Ngun, the prence of the distct molecular marks n predict homosexualy wh an accuracy of close to 70%. Geicists suggt that together, the human genome and s epigenome reflect the teractn of nature and nurture -- both our fixed herance and our bodi’ flexible rpons to the world -- makg who we ’s study of tws don’t reveal how or when a male tak on the epigenomic marks that distguish him as homosexual. ”To fd the epigenomic markers of male homosexualy, Ngun, a postdoctoral rearcher at UCLA’s Geffen School of Medice, bed through the geic material of 47 sets of intil male tws.

SCIENTISTS FD DNA DIFFERENC BETWEEN GAY MEN AND THEIR STRAIGHT TW BROTHERS

So they unleashed a mache learng algorhm on the data to search for regulari that distguished the epigenom of homosexual tw-pairs om tws which only one was ne pact regns sttered across the genome, they found patterns of epigenomic differenc that would allow a predictn far more accurate than a random gus of an dividual’s sexual orientatn, Ngun reported Thursday.

McCarthy and other experts utned that the disvery of epigenomic marks suggtive of homosexualy is a far cry om fdg the of sexual distctive epigenomic marks observed by Ngun and his lleagu uld rult om some other blogil or liftyle factor mon to homosexual men but unrelated to their sexualy, said Universy of Utah geicist Christopher Gregg. But the existence of intil tw pairs which only one is homosexual “nclively suggt that gen don’t expla everythg, ” Bailey Ngun’s rearch needs to be replited larger studi of tws, advanc the fful procs of better unrstandg how — and when — a boy’s sexual orientatn velops, Bailey me on Twter @LATMelissaHealy and “like” Los Angel Tim Science & Health on rarely get ncer, now scientists thk they know whyThree rearchers w Nobel Prize chemistry for studi of DNA repairMars had a long-lastg seri of lak, NASA’s Cursy rover fds. “The people participatg our study are terted ntributg to this kd of scientific knowledge and want to unrstand at least part of how they me to be the way they are, ” Sanrs search for ‘gay gen’ go back to 1993, when a US team led by Dr Dean Hamer scribed a regn of DNA loted on the X chromosome lled Xq28.

“Conservative, right-wg people hated bee they felt that was sayg that beg gay is like beg black, that was -born, that would somehow ‘exce’ gay people or give them more rights, ” says Hamer. “On the other hand, gay people hated too bee, at that time, there were fears that the disvery would be mised to abort gay babi and wipe gay people off the face of the Earth. ”More like thisAlthough the fears rema, recent years the search for ‘gay gen’ has bee more accepted by the gay muny, no small part bee a blogil explanatn would unrme arguments that beg gay is a social or liftyle choice.

GAY GEICS

The fact that intil tws have the same DNA and aternal tws share 50 per cent suggts that male homosexualy is gay geneIt was sctisg fay tre to see how homosexualy is hered that led Hamer to the disvery of Xq28.

Now chief of the gene stcture and regulatn sectn at the US Natnal Cancer Instute, his study revealed a cur pattern: gay men tend to have more gay uncl and gay male s on their mother’s si of the fay than on their father’s. This is bee mal her their X chromosome om their track down the DNA regn lked to the gay tra, Hamer ed a technique lled ‘lkage mappg’, an approach that lets geicists fd a gene even when they don’t know what do or where ’s loted. A subsequent study 1999 failed to replite Hamer’s rults and other rearchers are sceptil that Xq28 is lked to homosexualy at brothers, immune mothersMany scientists believe that exposure to hormon durg pregnancy heavily fluenc sexualy.

Durg pre-natal velopment, for example, the sex ans a foet n regnise ttosterone, which will swch on gen to make om a few superficial differenc (among them penis and rg-fger length – both longer homosexuals), gay and straight men’s bodi appear the same. The exceptn is homosexual men’s bras, which show remarkable siari to the bras of heterosexual women, suggtg that sexual orientatn pends on the effect hormon have on the velopg the two factors only go so far explag how homosexualy velops. ”Blanchard believ that homosexualy is “100 per cent blogil”, and timat that the aternal birth orr effect acunts for 15-30 per cent of gay men the populatn.

THERE’S NO ONE ‘GAY GENE,’ BUT GEICS ARE LKED TO SAME-SEX BEHAVR, NEW STUDY SAYS

Not only did he replite Blanchard’s birth orr effect, he also tected herance of homosexualy on the mother’s si, supportg Hamer’s ia of a gay gene on chromosome X.

THE LIFE OF THE GAY GENE: OM HYPOTHETIL GEIC MARKER TO SOCIAL REALY

After Camper Ciani scribed the observed patterns pedigre of homosexualy – the effects of maternal herance and birth orr – his dghter suggted that he re-check his data to see if the female relativ of gay men had more children on the mother’s si. “Mothers and nts on the maternal le of homosexuals had around one-fifth to one-fourth more kids than the heterosexual parison, and also than the paternal le. Nippl are another example of a sexually antagonistic tra: they’re need for feedg babi, but velopg nippl men is a waste of the body’s rourc and allow errors leadg to breast search for sexualyEven if Camper Ciani’s fecundy factors are the same as Hamer’s gay gen, don’t tell what the specific gen actually do.

Hamer speculat the gen might boost the size or nnectns om parts of the bra ed reproductn – such as the hypothalam – to make people more Sanrs’s study at NorthShore Universy uld fally reveal the inty and functn of ‘gay gen’.

MOM'S GEICS COULD PRODUCE GAY SONS

“People we talked to at gay pri ftivals have signer-baby kd of worri – a geic tt employed a pre-natal way, or for employment and surance discrimatn, maybe the ary too. The rearchers say that, although variatns the gen nnot predict whether a person is gay, the variants may partly fluence sexual Ganna, lead thor and European Molecular Blogy Laboratory group lear at the Instute of Molecular Medice Fland, said the rearch rerc the unrstandg that same-sex sexual behavr is simply “a natural part of our diversy as a speci.

Some of the variants were rrelated wh same-sex sexual behavr men, others women, and some Vila, director of the Center for Geic Medice Rearch at Children’s Natnal Health System, said the study marks the end of “the simplistic ncept of the ‘gay gene. Environmental effects may be a factor for some people; for stance, havg olr brothers creas the odds that younger brothers will be gay, which rearchers spect may have to do wh chang to the mother’s immune system rponse to the earlier Stok, chief programs officer for GLAAD, said a statement that the new rearch on the geics “provis even more evince that beg gay or lbian is a natural part of human life, a ncln that has been drawn by rearchers and scientists time and aga. However, spe such tenuo provenance, the gay gene has persisted as a reference science news, popular science wrgs, and prs releas and edorials about bmedil rearch.

News media monstrat that the gay gene has bee an assumed back-story to geic sexualy rearch over time, and that the crique of s very existence has been dimished. The arrangement of a mother's gen uld affect the sexual orientatn of her son, acrdg to a new fdg, tailed the Febary issue of the journal Human Geics, adds fuel to the -long bate about whether so-lled "gay gen" might rearchers examed a phenomenon lled "X chromosome activatn" 97 mothers of gay sons and 103 mothers whose sons were not gay. However, when the rearchers the current study examed cells om the 42 mothers who had at least two gay sons, they found that about a quarter of the women this group showed somethg different.

NO ‘GAY GENE’: MASSIVE STUDY HOM ON GEIC BASIS OF HUMAN SEXUALY

"We thk that there are one or more gen on the X chromosome that have an effect on the sexual orientatn of the sons of the mothers, as well as an effect on the cells we were lookg at, " Bocklandt chromosom implitedBocklandt was also volved an earlier study that looked at the entire human genome of men who had two or more gay brothers. The rearchers found intil stretch of DNA on three chromosom—7, 8 and 10—that were shared by about 60 percent of the gay brothers the study also found mothers to have an unually large role their son's sexual orientatn: the regn on chromosome 10 rrelated wh homosexualy only if was hered om the rults om the two studi suggt that there are multiple geic factors volved termg a person's sexual orientatn and that might vary pendg on the person. "We thk that there are gog to be some gay men who are X chromosome gay men and some who are chromosome 7 gay men or chromosome 10 gay men or some batn, " Bocklandt said a telephone rearchers now thk that there is no sgle gay gene that ntrols whether a person is homosexual or not.

MANY GEN INFLUENCE SAME-SEX SEXUALY, NOT A SGLE ‘GAY GENE’

Relig lears who believe that sexual orientatn is a choice argue that such rearch is an attempt to legimize homosexualy; others worry that a tailed knowledge of the geics unrlyg homosexualy will open the door to geic engeerg that prevents Bocklandt don't thk the ncerns should prevent scientists om askg the basic qutn of whether homosexualy has an unrlyg geic ponent to or not.

“There is no ‘gay gene’, ” says lead study thor Andrea Ganna, a geicist at the Broad Instute of MIT and Harvard Cambridge, and his lleagu also ed the analysis to timate that up to 25% of sexual behavur n be explaed by geics, wh the rt fluenced by environmental and cultural factors — a figure siar to the fdgs of smaller studi. Muny there said they were worried the fdgs uld give ammunn to people who seek to e science to bolster bias and discrimatn agast gay ncern is that evince that gen fluence same-sex behavr uld e anti-gay activists to ll for gene edg or embryo selectn, even if that would be technilly impossible. Dpe s limatns, the rearch was much larger and more varied than prev studi, which generally foced on gay men, often those who were tws or were otherwise related.

HOW OUR GEN ULD MAKE GAY OR STRAIGHT

“That right there is the big issue wh lookg for the geics of sexual orientatn — social ntext uld be a big part of the exprsn of the tra, ” said Jeremy Yor, an assistant profsor of blogy at California State Universy, Northridge, who is gay and follows geic rearch the field.

IS THERE A "GAY GENE"? MAJOR NEW STUDY SAYS NO

He and others noted that olr participants me of age when homosexual behavr was crimalized Bra and that for much of their life homosexualy was classified as a psychiatric Reilly and others said such stark differenc between olr and younger participants show the tricks of tryg to draw reprentative blogil rmatn om a study populatn so strongly fluenced by society’s changg attus. Dean Hamer, a former Natnal Instut of Health scientist who led the first high-profile study intifyg a geic lk to beg gay 1993, said he was happy to see such a large rearch effort. More about Pam BelluckA versn of this article appears prt on, Sectn A, Page 1 of the New York edn wh the headle: Rearch Fds Not One ‘Gay Gene, ’ but a Multu of Influenc.

It wouldn't be right if we didn't mentn this new rearch supportg the hypothis that sexual orientatn has got a geic rearch adds a twist to the bate on the origs of sexual orientatn, suggtg that the geics of mothers of multiple gay sons act differently than those of other women.

Normally, women randomly procs the chromosom one of two ways -- half go one way, half go the rearch "nfirms that there is a strong geic basis for sexual orientatn, and that for some gay men, gen on the X chromosome are volved, " said study -thor Sven Bocklandt, a postdoctoral rearcher at the Universy of California at Los lk between geics and sexual orientatn has been a hot topic for more than a as a few scientists have tried to fd gen that might make people gay or straight. "In the new study, rearchers looked at 97 mothers of gay sons and 103 mothers whout gay sons to see if there was any difference how they handled their X chromosom. "When we looked at women who have gay kids, those wh more than one gay son, we saw a quarter of them activate the same X virtually every cell we checked, " Bocklandt said.