Epigenetic algorithm accurately predicts male sexual orientation in small group

http://www.eurekalert.org/pub_releases/2015-10/asoh-eaa093015.php

Public Release: 8-Oct-2015
Epigenetic algorithm accurately predicts male sexual orientation
Findings reported at ASHG 2015 Annual Meeting
American Society of Human Genetics

An algorithm using epigenetic information from just nine regions of the human genome can predict the sexual orientation of males with up to 70 percent accuracy, according to research presented at the American Society of Human Genetics (ASHG) 2015 Annual Meeting in Baltimore.

•••••

Beyond the genetic information contained in DNA, the researchers examined patterns of DNA methylation - a molecular modification to DNA that affects when and how strongly a gene is expressed - across the genome in pairs of identical male twins. While identical twins have exactly the same genetic sequence, environmental factors lead to differences in how their DNA is methylated. Thus, by studying twins, the researchers could control for genetic differences and tease out the effect of methylation. In all, the study involved 37 pairs of twins in which one twin was homosexual and the other was heterosexual, and 10 pairs in which both twins were homosexual.

•••••

They found that methylation patterns in nine small regions, scattered across the genome, could be used to predict study participants' sexual orientation with 70 percent accuracy.

"Previous studies had identified broader regions of chromosomes that were involved in sexual orientation,

•••••

http://www.scientificamerican.com/article/experts-cautious-about-study-predicting-gay-orientation/?WT.mc_id=SA_WR_20151014

Experts Cautious about Study Predicting "Gay" Orientation

By Bill Berkrot
Oct. 9, 2015

(Reuters) - U.S. researchers on Thursday said they had found a way to predict male sexual orientation based on molecular markers that control DNA function, but genetics experts warned that the research has important limitations and will not provide definitive answers to a potential biological basis for sexual preference.

•••••

"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.

•••••

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