Genes linked to homosexuality identified

Washington: Scientists have discovered genetic variants linked to homosexuality by analysing the entire DNA codes of gay and heterosexual men.

They discovered that DNA was different for gay and straight men around two genes: SLITRK5 and SLITRK6.

The study, published in the journal Scientific Reports, is the first to look at the complete genome of over 1,000 homosexual men and compare it to genetic data from 1,231 heterosexual males.

SLITRK6 is an important gene for brain development and is particularly active in the brain region which includes the hypothalamus.

The hypothalamus is crucial for producing hormones linked to control sex drive. Previous studies have shown that parts of it are up to 34 per cent larger in gay men.

Researchers from North Shore University Health System (NSUHS) in the US also discovered differences in the TSHR gene, which is linked to the thyroid, The Telegraph reported.

"Because sexuality is an essential part of human life ? for individuals and society ? it is important to understand the development and expression of human sexual orientation," said Alan Sanders, from NSUHS.

"The goal of this study was to search for genetic underpinnings of male sexual orientation, and thus ultimately increase our knowledge of biological mechanisms underlying sexual orientation," Sanders said.

However, experts suggest that the number of participants in the study is too small to draw population-wide conclusions, and the findings are not statistically significant.

"Even if a gene variant does show some correlation with sexual orientation, this does not mean that the gene is in any way responsible for being gay ? it just means it has some association with a trait that is more likely to found in the relatively few people involved as subjects in the study," said Robin Lovell-Badge from The Francis Crick Institute in the UK, who was not involved in the study.