Is There a 'Gay Gene'? Rearchers Thk So

Contents:

• NEW THEORY: THE GAY TRA IS PASSED DOWN FROM PARENT TO CHILD
• MANY GEN INFLUENCE SAME-SEX SEXUALY, NOT A SGLE ‘GAY GENE’
• IS THERE A 'GAY GENE'? REARCHERS THK SO

NEW THEORY: THE GAY TRA IS PASSED DOWN FROM PARENT TO CHILD

For the first time, rearchers have found associatns between homosexualy and markers attached to DNA that n be fluenced by environmental studi and fay tre provi strong evince that sexual orientatn is at least partly geic. The 'epi-marks' n be hered, but n also be altered by environmental factors such as smokg, and are not always shared by intil rearchers llected DNA sampl saliva om 37 pairs of intil tws which only one tw was gay, and 10 pairs which both were gay.

Ngun says that the rearchers want to replite the study a different group of tws and also terme whether the same marks are more mon gay men than straight men a large and diverse populatn. Pedigree and tw studi dite that homosexualy has substantial herabily both sex, yet nrdance between intil tws is low and molecular studi have failed to fd associated DNA makers. In this mol, homosexualy occurs when stronger-than-average SA-epi-marks (fluencg sexual preference) om an oppose-sex parent pe erasure and are then paired wh a weaker-than-average novo sex-specific epi-marks produced oppose-sex offsprg.

Our mol predicts that homosexualy is part of a wir phenomenon which recently evolved androgen-fluenced tras monly display gonad-tra disrdanc at substantial equency, and that the molecular feature unrlyg most homosexualy is not DNA polymorphism(s), but epi-marks that evolved to nalize sexual dimorphic velopment that sometim rryover across generatns and ntribute to gonad-tra disrdanc oppose-sex scendants. 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.

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

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. Instead of tras gettg passed down through the gen, epigeic change happens bee of the way gen are regulated, or turned on and geic regulators may be the reason homosexualy persists nature spe the fact that gay people are ls likely to reproduce, suggts the new study published the journal The Quarterly Review of Blogy.

In a male fet, Rice and his lleagu wre, an epigeic change that benefed the mother may lead to "femizatn" of sexual preference — homo- or bisexualy.

)The fdgs add to past rearch suggtg gay men haven't died out, bee female relativ of gay men tend to have more children on average than other femal.

IS THERE A 'GAY GENE'? REARCHERS THK SO

Epigeics, however, n expla the herabily whout the need for a specific geic hypothis uld be tted by examg epigeic marks parents of kids wh gay vers straight offsprg, Rice said. There are, of urse, ncerns that this knowledge uld be ed by parents who want to avoid gay offsprg, Rice said, but that ncern already exists around certa hormonal ndns utero, which are known to ntribute to an creased chance of offsprg beg lbians. Analys have noted that homosexualy n n fai, leadg rearchers to hypothize a geic unrpng of sexual preference but no gene or group of gen for homosexualy have been found, spe numero studi searchg for a geic nnectn.

A paper The Quarterly Review of Blogy says that sex-specific epi-marks, which normally do not pass between generatns and are th "erased, " n lead to homosexualy when they pe erasure and are transmted om father to dghter or mother to son. They tegrated evolutnary theory wh molecular regulatn of gene exprsn and androgen-pennt sexual velopment to produce a blogil and mathematil mol that leat the role of epigeics homosexualy.

They say their study solv the evolutnary aspect of homosexualy, fdg that "sexually antagonistic" epi-marks, which normally protect parents om natural variatn sex hormone levels durg fetal velopment, sometim rryover across generatns and e homosexualy oppose-sex offsprg. "Transmissn of sexually antagonistic epi-marks between generatns is the most plsible evolutnary mechanism of the phenomenon of human homosexualy, " said -thor Sergey Gavrilets, Ph.