Important Announcement

See here for an important message regarding the community which has become a read-only site as of October 31.

 
Post Reply
Page 1 of 19  •  1 2 3 4 5 6 ... 19 Next
Switch to Forum Live View Epigenetics and Male Sexual Orientation
1 year ago  ::  Oct 09, 2015 - 4:56PM #1
REteach
Posts: 16,577
My genetics boss is at ASHG (American Society of Human Genetics).  One of the presentations was on an algorith that correctly predicted male sexual orientation with 70% by looking at epigenetic changes in 9 regions of the genome. 



Tuck c Ngun was the first author on the study  This study looked at methylation patterns in 47 identical twins.



       (considering over 150 genes have been implicated in height so far, that is pretty impressive)
I know you believe you understand what you think I said, but I am not sure you realize what you heard was not what I meant...
Quick Reply
Cancel
1 year ago  ::  Oct 09, 2015 - 5:09PM #2
MMarcoe
Posts: 20,907

Do you have any links to articles on this?

1. Extremists think that thinking means agreeing with them.
2. There are three sides to every story: your side, my side, and the truth.
3. God is the original nothingness of the universe.
Quick Reply
Cancel
1 year ago  ::  Oct 09, 2015 - 5:28PM #3
SeraphimR
Posts: 12,687

Oct 9, 2015 -- 4:56PM, REteach wrote:

My genetics boss is at ASHG (American Society of Human Genetics).  One of the presentations was on an algorith that correctly predicted male sexual orientation with 70% by looking at epigenetic changes in 9 regions of the genome. 



Tuck c Ngun was the first author on the study  This study looked at methylation patterns in 47 identical twins.



       (considering over 150 genes have been implicated in height so far, that is pretty impressive)



I can predict male sexual orientation 97% of the time simply by guessing heterosexual each time.

“So long as there is squalor in the world, those obsessed with social justice feel obliged not only to live in it themselves but also to spread it evenly.”

http://takimag.com/article/the_ugly_truth_theodore_dalrymple
Quick Reply
Cancel
1 year ago  ::  Oct 09, 2015 - 6:58PM #4
Qwesam
Posts: 3,369

Oct 9, 2015 -- 5:28PM, SeraphimR wrote:


Oct 9, 2015 -- 4:56PM, REteach wrote:

My genetics boss is at ASHG (American Society of Human Genetics).  One of the presentations was on an algorith that correctly predicted male sexual orientation with 70% by looking at epigenetic changes in 9 regions of the genome. 



Tuck c Ngun was the first author on the study  This study looked at methylation patterns in 47 identical twins.



       (considering over 150 genes have been implicated in height so far, that is pretty impressive)



I can predict male sexual orientation 97% of the time simply by guessing heterosexual each time.




Actually, it should be 93%.


Anyway, the study uses scientific finding base on genes. By logic, if it is guessing,  it should be 50% - 50%.


If it is 70%, it is scientific study, not base on guessing.


***Watching Foxnews makes you dumb and dumber than your friends who watch NO News. It is on the survey!

***Don’t listen to what Republicans say, look what they do to Women’s rights.

***Being required to serve those we dislike is a painful price to pay for the privilege of running a business; but the pain exclusion inflicts on its victims is far worse.

Garrett Epps
Quick Reply
Cancel
1 year ago  ::  Oct 09, 2015 - 7:45PM #5
Erey
Posts: 21,730

but isn't epigenetics sort of loosey goosey?  


I mean people develop all kinds of sexual orientations based on environmental and experience factors.   Some people are challenged with overcoming what could be in the epigenetic arena and are able to do so.


To me this seems like solving one of those maze puzzles by begining at the end and forging a pathway that works for you.   You have the conclusion you want and you make the facts work for you.



AGain,  I dont' care how or why people are gay.  I just don't believe everyone who is gay is gay for the same reason (epigenetics).  Some might be,  others not so much.

Quick Reply
Cancel
1 year ago  ::  Oct 09, 2015 - 9:26PM #6
KindredSai
Posts: 7,425

Oct 9, 2015 -- 7:45PM, Erey wrote:


but isn't epigenetics sort of loosey goosey?  


I mean people develop all kinds of sexual orientations based on environmental and experience factors.   Some people are challenged with overcoming what could be in the epigenetic arena and are able to do so.


To me this seems like solving one of those maze puzzles by begining at the end and forging a pathway that works for you.   You have the conclusion you want and you make the facts work for you.



AGain,  I dont' care how or why people are gay.  I just don't believe everyone who is gay is gay for the same reason (epigenetics).  Some might be,  others not so much.




Surely there's a genetic reason why the vast majority of homosexuals are homosexual, as much as why heterosexuals are heterosexual. I don't buy into the idea it's environmental - those are archaic reasons.

Quick Reply
Cancel
1 year ago  ::  Oct 10, 2015 - 12:03PM #7
mindis1
Posts: 9,330

REteach, have you read the study? The following article notes that it has not been reviewed or published. The article also includes comments from others in the field:


Genetics experts who critiqued the findings said it was premature to draw any conclusions on the predictive powers of epigenetic markers.


"The question as to whether that prediction is going to be useful outside of the small number of twins in the study is really unclear," said Dr. Christopher Gregg, a genetics professor at the University of Utah.


Others noted the small size of the population studied and stressed that such findings often fall apart when applied to larger groups of people.


"One thing you can clearly see is that the sample size is too small. They don't have enough power to make that claim," said Dr. Peng Jin, professor of human genetics from Emory University in Atlanta, who attended the meeting in Baltimore.


"What they are seeing may be certain correlations, but I don't think they have what they claim, which is a predicting model," he added. "It's definitely an interesting observation, but ... I don't want the general audience to misinterpret whatever they are presenting," Jin said.


Gregg said he was impressed by the UCLA team's "state-of-the-art" methodology, but said much larger studies must be undertaken to reach any conclusions.


"Just because there is something different doesn't mean that's what's causing people to behave one way versus the other," he said.


news.yahoo.com/experts-caution-study-cit...


Are the epigenetic marks (is that the right term?) that were studied heritable?

Moderated by Merope on Oct 15, 2015 - 08:30PM
Quick Reply
Cancel
1 year ago  ::  Oct 10, 2015 - 12:09PM #8
mindis1
Posts: 9,330

Oct 9, 2015 -- 9:26PM, KindredSai wrote:


Surely there's a genetic reason why the vast majority of homosexuals are homosexual, as much as why heterosexuals are heterosexual. I don't buy into the idea it's environmental - those are archaic reasons.



Epigenetics is an environmental effect on the genome.


What I am skeptical of is the idea that sexual orientation in humans is a binary, which is the assumption of all biological studies on sexual orientation that I’ve seen, and is apparently the underlying assumption of the topical study. Other animals, notably our closest living non-human relatives, do not exhibit a binary sexual orientation. Biological Exuberance by Bruce Bagemihl documents a huge variety of normal non-heterosexual activity among dozens of species, and very rarely are any exclusively monosexual individuals observed. How did Homo sapiens become trapped in this anomalous biology where the sexual norm is supposedly unwavering heterosexuality, with only a small group of supposedly epigenetically aberrant non-heterosexuals? I’m unaware that anyone has ever attempted an explanation as to how humans supposedly evolved such a peculiar biological sexuality that contrasts so markedly with what is observed among all other living hominids.


All biological studies of human sexual orientation that I’ve seen treat non-heterosexuality exactly like a disease--a behavioral deviation from the norm. Human history doesn’t endorse such assumptions. In ancient and more recent primitive cultures uninfluenced by the perversities of modern Western society (which has relentlessly persecuted same-sex sexual activity for centuries), large portions of or virtually all individuals have evinced unequivocal bisexuality. Ironically you won’t find a single biological study that proceeds on the assumption that monosexuality is the behavioral aberration, despite the overwhelming historical evidence that this is precisely the case. 

Quick Reply
Cancel
1 year ago  ::  Oct 12, 2015 - 1:58PM #9
mindis1
Posts: 9,330

An article by Ed Yong in The Atlantic provides further critiques of the study:


The problems begin with the size of the study, which is tiny. The field of epigenetics is littered with the corpses of statistically underpowered studies like these, which simply lack the numbers to produce reliable, reproducible results.


Unfortunately, the problems don’t end there. The team split their group into two: a “training set” whose data they used to build their algorithm, and a “testing set”, whose data they used to verify it. That’s standard and good practice -- exactly what they should have done. But splitting the sample means that the study goes from underpowered to really underpowered.


There’s also another, larger issue. As far as could be judged from the unpublished results presented in the talk, the team used their training set to build several models for classifying their twins, and eventually chose the one with the greatest accuracy when applied to the testing set. That’s a problem because in research like this, there has to be a strict firewall between the training and testing sets; the team broke that firewall by essentially using the testing set to optimise their algorithms.


If you use this strategy, chances are you will find a positive result through random chance alone. Chances are some combination of methylation marks out of the original 6,000 will be significantly linked to sexual orientation, whether they genuinely affect sexual orientation or not. This is a well-known statistical problem that can be at least partly countered by running what’s called a correction for multiple testing. The team didn’t do that. (In an email to The Atlantic, Ngun denies that such a correction was necessary.)


And, “like everyone else in the history of epigenetics studies they could not resist trying to interpret the findings mechanistically,” wrote John Greally from the Albert Einstein College of Medicine in a blog post. By which he means: they gave the results an imprimatur of plausibility by noting the roles of the genes affected by the five epi-marks. One is involved in controlling immune genes that have been linked to sexual attraction. Another is involved in moving molecules along neurons. Could epi-marks on these genes influence someone’s sexual attraction? Maybe. It’s also plausible that someone’s sexual orientation influences epi-marks on these genes. Correlation, after all, does not imply causation.


So, ultimately, what we have is an underpowered fishing expedition that used inappropriate statistics and that snagged results which may be false positives. Epigenetics marks may well be involved in sexual orientation. But this study, despite its claims, does not prove that and, as designed, could not have.


www.theatlantic.com/science/archive/2015...


Hyperlinked in the article is the chapter on statistical power in a highly informative online version of the book Statistics Done Wrong, by Alex Reinhart. Statistical power is the probability that a study will be able to distinguish an effect of a certain size from mere chance. Reinhart first goes through the simple example in which one is trying to detect whether a coin being flipped is a fair coin or one rigged to give heads 60% of the time. As anyone can demonstrate for him/herself, flipping a coin 50 times rarely yields 25 heads and 25 tails. However the Law of Large Numbers dictates that the more flips one performs, the closer one gets to the true percentage difference. A coin that gives heads 600 times out of 1000 flips is almost certainly rigged. Reinhart goes on to note some interest facts about medical trials:


[Y]ou might think calculations of statistical power are essential to medical trials. A scientist might want to know how many patients are needed to test if a new medication improves survival by more than 10%, and a quick calculation of statistical power would provide the answer. Scientists are usually satisfied when the statistical power is 0.8 or higher, corresponding to an 80% chance of concluding there’s a real effect.


However, few scientists ever perform this calculation, and few journal articles ever mention the statistical power of their tests.


Consider a trial testing two different treatments for the same condition. You might want to know which medicine is safer, but unfortunately, side effects are rare. You can test each medicine on a hundred patients, but only a few in each group suffer serious side effects.


Obviously, you won’t have terribly much data to compare side effect rates. If four people have serious side effects in one group, and three in the other, you can’t tell if that’s the medication’s fault.


Unfortunately, many trials conclude with “There was no statistically significant difference in adverse effects between groups” without noting that there was insufficient data to detect any but the largest differences.[57] And so doctors erroneously think the medications are equally safe, when one could well be much more dangerous than the other.


You might think this is only a problem when the medication only has a weak effect. But no: in one sample of studies published between 1975 and 1990 in prestigious medical journals, 27% of randomized controlled trials gave negative results, but 64% of these didn’t collect enough data to detect a 50% difference in primary outcome between treatment groups. Fifty percent! Even if one medication decreases symptoms by 50% more than the other medication, there’s insufficient data to conclude it’s more effective. And 84% of the negative trials didn’t have the power to detect a 25% difference.[17, 4, 11, 16]


In neuroscience the problem is even worse. Suppose we aggregate the data collected by numerous neuroscience papers investigating one particular effect and arrive at a strong estimate of the effect’s size. The median study has only a 20% chance of being able to detect that effect. Only after many studies were aggregated could the effect be discerned. Similar problems arise in neuroscience studies using animal models -- which raises a significant ethical concern. If each individual study is underpowered, the true effect will only likely be discovered after many studies using many animals have been completed and analyzed, using far more animal subjects than if the study had been done properly the first time.[12]


www.statisticsdonewrong.com/power.html


So much for “evidence-based medicine”. 

Quick Reply
Cancel
1 year ago  ::  Oct 12, 2015 - 4:59PM #10
REteach
Posts: 16,577

My genetics boss sent the link from ASHAG where it was being presented to a group of geneticists, who are well aware of the problems with sample size and power, but where sample size is often dinky--a couple of kindreds.  Instead of 0.01 or 0.05 for significance, the level might be 1 to the 100th power.  They are well aware of the dangers of finding significant results from running tens of thousands of tests simultaneously.


Environment in this case does not even mean after birth.  Identical twins do not have identifical intrauterine experience/exposures.  So this does not mean parenting. 


I tend to look at epigenetics as if our genes were all down a long hallway. Some doors are open, some closed, some locked open or shut, and other capable of being opened and closes or locked and unlocked.  Epigenetics is simply about opening and closing, locking or unlocking those doors.  Hormone definitely can do that and there is some support that testosterone is a big one in sexual orientation.  There is also some speculation that mothers may develop antitestosterone antibodies.


In any case, this is not some kind of "proof."  It is support for the idea that there is a genetic predisposition that is affected by the environment--a big part of which is testosterone.

I know you believe you understand what you think I said, but I am not sure you realize what you heard was not what I meant...
Quick Reply
Cancel
Page 1 of 19  •  1 2 3 4 5 6 ... 19 Next
 
    Viewing this thread :: 0 registered and 1 guest
    No registered users viewing
    Advertisement

    Beliefnet On Facebook