Epigenetic Marks Tied to Homosexuality
In a recent study of male twins, nine methylation sites helped researchers predict a person's sexual orientation. Throughout the study, it had been examined its genome and determining whether the individuals are methylated can peg sexual orientation with nearly 70 percent accuracy. The idea of epigenetics influencing sexual orientation had been proposed several years ago, but had been more recently examined in today's generation. Researchers had found that methylation status of nine regions in the genome could identify sexual orientation with a significant percent accuracy. Margaret McCarthy, a scientist at the University of Maryland School of Medicine stated, "This study provides a major step forward in our understanding of how the brain can be affected by factors outside of the genome. It is also possible that the experience of being a homosexual or a heterosexual has itself impacted the epigenetic profile. But regardless of when, or even how, these epigenetic changes occur, their findings demonstrate a biological basis to partner preference". It is also true that pinpointing the exact origins of this biological basis is a thorny issue. More work must be done to uncover the functional significance of the methylation profiles. Some scientists expressed caution in interrupting early data from a small study.
Additionally, twin studies and family trees provide strong evidence that sexual orientation is at least partially genetic. When one identical twin is gay, there is about 20% chance that the other will be as well. Due to the fact that this rate is not 100%, it is thought that environmental factors play a role as well and this can be characterized as the 'older brother effect', which is that chance is a man being gay increases by 33% for each older brother he has. This reason is not clear, but one hypothesis holds that the mother's immune system begins to react against male antigens and alter the fetus's development. In my opinion, I think a genome being able to tell if a person is homosexual or heterosexual is absolutely outrageous. I always believed a persons sexuality preference is their personal desire, not determined from a gene in your brain. I also think that the topic is not researched enough where it can prove this theory to be accurate.
Link to article:
Link to alternative article:http://www.nature.com/news/epigenetic-tags-linked-to-homosexuality-in-men-1.18530