[Rushtalk] Scientists find DNA differences between gay men and their straight twin brothers
Stephen A. Frye
s.frye at verizon.net
Tue Nov 10 14:04:42 MST 2015
It's not clear yet. The claim is that environment 'can' contribute, and likely does contribute, but no one is sure to what extent. And even environment isn't definitive: parents, siblings, teachers, the garbage man?
The nature vs. nurture battle will rage long after we're gone. Hard-lined liberals will forever rant about purely nature, and hard-lined conservatives will forever rant about "choice", as it allows us to wag the finger of accusation and condemnation. Until we can all get past that, the mater will never resolve.
From: rushtalk-bounces at csdco.com [mailto:rushtalk-bounces at csdco.com] On Behalf Of Steven Laib
Sent: Tuesday, November 10, 2015 12:14 PM
To: Rushtalk Discussion List
Subject: Re: [Rushtalk] Scientists find DNA differences between gay men and their straight twin brothers
I'm not sure, but if I read the piece correctly it seemed to indicate that the trait was a result of environmental factors and not inherited.
Did I miss something?
Sent from my iPhone
> On Nov 10, 2015, at 12:43 PM, Tom Matiska <tom.matiska at att.net> wrote:
> Most genetic traits are inherited. Until same sex couples start passing their genes and dna to their offspring we are stuck with the fact almost all gays are the offspring of heteros.... give or take a few bi couples... Tom
> T-Mobile. America's First Nationwide 4G Network
> Dennis Putnam <dap1 at bellsouth.net> wrote:
>> Agree. If it is genetic the homosexual community will go ballistic if
>> anyone suggests research to find a cure.
>>> On 11/9/2015 9:35 PM, Stephen A. Frye wrote:
>>> Of course you think it’s a fraud. If it turns out to be anything
>>> other than 100% free choice, it hurts our whole perspective.
>>> Science be damned – full speed ahead!
>>> *From:*rushtalk-bounces at csdco.com
>>> [mailto:rushtalk-bounces at csdco.com]
>>> *On Behalf Of *John A. Quayle
>>> *Sent:* Monday, November 09, 2015 4:50 PM
>>> *To:* Rushtalk Discussion List; Rushtalk
>>> *Subject:* Re: [Rushtalk] Scientists find DNA differences between
>>> gay men and their straight twin brothers
>>> */_IF_/**/this is true (and I'm thinking it's a complete
>>> fraud), the God's got some apologizing to do those who lived in
>>> ancient Sodom and Gomorrah................. - jaq
>>> /*At 03:25 PM 11/8/2015, Carl Spitzer wrote:
>>> Scientists find DNA differences between gay men and their straight
>>> twin brothers
>>> Homosexuality epigenome markers Could the molecular signals that
>>> turn genes on and off reveal a person's sexual orientation? New
>>> research identifies epigenomic "marks" linked to homosexuality. But
>>> experts say the origins of partner preference remain a mystery.
>>> (Chuck Nigash ,Stephen Sedam / Los Angeles Times) Melissa
>>> HealyMelissa Healy
>>> ne> For men, new research suggests that clues to sexual orientation
>>> may lie not just in the genes, but in the spaces between the DNA,
>>> where molecular marks instruct genes when to turn on and off and how
>>> strongly to express themselves.
>>> On Thursday, UCLA molecular biologist Tuck C. Ngun
>>> ion>reported that in studying the genetic material of 47 pairs of
>>> identical male twins, he has identified "epigenetic marks" in nine
>>> areas of the human genome that are strongly linked to male
>>> In individuals, said Ngun, the presence of these distinct molecular
>>> marks can predict homosexuality with an accuracy of close to 70%.
>>> That news, presented at the 2015 meeting of the American Society of
>>> Human Genetics on Thursday, may leave the genetically uninitiated
>>> scratching their heads.
>>> But experts said the results -- as yet unpublished in a
>>> peer-reviewed journal -- offer preliminary new evidence that a man's
>>> genetic inheritance is only one influence on his sexual orientation.
>>> Through the epigenome, the results suggest, some facet of life
>>> experience likely also primes a man for same-sex attraction.
>>> DNA from 4,500-year-old Ethiopian reveals surprise about ancest
>>> an-dna-eurasia-20151008-story.html> DNA from 4,500-year-old
>>> Ethiopian reveals surprise about ancestry of Africans
>>> Over a person's lifetime, myriad environmental factors -- nutrition,
>>> poverty, a mother's love, education, exposure to toxic chemicals --
>>> all help shape the person he will become.
>>> Researchers working in the young science of epigenetics acknowledge
>>> they are unsure just how an individual's epigenome is formed. But
>>> they increasingly suspect it is forged, in part, by the stresses and
>>> demands of external influences. A set of chemical marks that lies
>>> between the genes, the epigenome changes the function of genetic
>>> material, turning the human body's roughly 20,000 protein-coding
>>> genes on or off in response to the needs of the moment.
>>> While genes rarely change over a lifetime, the epigenome is
>>> constantly changing.
>>> Geneticists suggest that together, the human genome and its
>>> epigenome reflect the interaction of nature and nurture -- both our
>>> fixed inheritance and our bodies' flexible responses to the world --
>>> in making us who we are.
>>> Ngun's study of twins doesn't reveal how or when a male takes on the
>>> epigenomic marks that distinguish him as homosexual. Many
>>> researchers believe that a person's eventual sexual preferences are
>>> shaped in the uterus
>>> <http://articles.latimes.com/2006/jun/27/science/sci-brothers27>, by
>>> hormonal shifts during key stages of fetal brain development.
>>> *FROM THE ARCHIVES: A closer look at scientific inquiry into sexual
>>> orientation <http://articles.latimes.com/2001/may/21/health/he-533>*
>>> By imprinting themselves on the epigenome, though, environmental
>>> influences may powerfully affect how an individual's genes express
>>> themselves over the course of his life. Ngun's findings suggest they
>>> may interact with genes to nudge sexual orientation in one direction
>>> or the other.
>>> "The relative contributions of biology versus culture and experience
>>> in shaping sexual orientation in humans continues to be debated,"
>>> said University of Maryland pharmacology professor Margaret M.
>>> McCarthy, who was not involved in the current study. "But regardless
>>> of when, or even how, these epigenetic changes occur," she added,
>>> the new research "demonstrates a biological basis to partner preference."
>>> To find the epigenomic markers of male homosexuality, Ngun, a
>>> postdoctoral researcher at UCLA's Geffen School of Medicine, combed
>>> through the genetic material of 47 sets of identical male twins.
>>> Thirty-seven of those twin sets were pairs in which one was
>>> homosexual and the other was heterosexual. In 10 of the pairs
>>> studied, both twins identified as homosexual.
>>> In identical twins, DNA is shared and overlaps perfectly. But the
>>> existence of twin pairs in which one is homosexual and the other is
>>> not offers strong evidence that something other than DNA alone
>>> influences sexual orientation. Ngun and his colleagues looked for
>>> patterns of DNA methylation -- the chemical process by which the
>>> epigenome is encoded -- to identify the missing factor in partner
>>> Their analysis generated a dataset far too large for a team of
>>> humans to make sense of. So they unleashed a machine learning
>>> algorithm on the data to search for regularities that distinguished
>>> the epigenomes of homosexual twin-pairs from twins in which only one was homosexual.
>>> In nine compact regions scattered across the genome, they found
>>> patterns of epigenomic differences that would allow a prediction far
>>> more accurate than a random guess of an individual's sexual
>>> orientation, Ngun reported Thursday.
>>> McCarthy and other experts cautioned that the discovery of
>>> epigenomic marks suggestive of homosexuality is a far cry from
>>> finding the causes of sexual preference.
>>> The distinctive epigenomic marks observed by Ngun and his colleagues
>>> could result from some other biological or lifestyle factor common
>>> to homosexual men but unrelated to their sexuality, said University
>>> of Utah geneticist Christopher Gregg. They could correlate with
>>> homosexuality but have nothing to do with it.
>>> “Epigenetic marks are the consequence of complex interactions
>>> between the genetics, development and environment of an individual,"
>>> said University of Cambridge geneticist Eric Miska. "Simple
>>> correlations -- if significant -- of epigenetic marks of an
>>> individual with anything from favorite football player to disease
>>> risk does not imply a causal relationship or understanding.”
>>> One longtime researcher in the field of sexual orientation praised
>>> Ngun’s use of identical twins as a means of teasing apart the
>>> various biological factors that influence the trait.
>>> “Our best guess is that there are genes” that affect a man’s sexual
>>> orientation “because that’s what twin studies suggest,” said
>>> Northwestern University psychologist J. Michael Bailey, who has
>>> explored a range of physiological markers that point to
>>> homosexuality’s origins in the womb. But the existence of identical
>>> twin pairs in which only one is homosexual “conclusively suggest
>>> that genes don’t explain everything,” Bailey added.
>>> While Ngun’s research needs to be replicated in larger studies of
>>> twins, it advances the fitful process of better understanding how
>>> and when a boy’s sexual orientation develops, Bailey said.
>>> *Follow me on Twitter @LATMelissaHealy
>>> <https://twitter.com/LATMelissaHealy> and "like" Los Angeles Times
>>> Science & Health <https://www.facebook.com/latimesscience> on
>>> So why not test for it and adjust insurance premiums according to risk??
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