In DepthBehavioral Genetics

Can epigenetics explain homosexuality puzzle?

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Science  09 Oct 2015:
Vol. 350, Issue 6257, pp. 148
DOI: 10.1126/science.350.6257.148

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A new study suggests that epigenetic effects—chemical modifications of the human genome that alter gene activity without changing the DNA sequence—may sometimes influence sexual orientation. Researchers studied methylation, the attachment of a methyl group to specific regions of DNA, in 37 pairs of male identical twins who were discordant—meaning that one was gay and the other straight—and 10 pairs who were both gay. Their search yielded five genome regions where the methylation pattern appears very closely linked to sexual orientation. A model that predicted sexual orientation based on these patterns was almost 70% accurate within this group—although that predictive ability does not necessarily apply to the general population.