ROUND-UP: Epigenetics and homosexuality (Quarterly Review of Biology*) – expert responds

Thu Dec 13, 2012

EMBARGO LIFTED 00:01am AEST Wednesday 12 December, 2012

According to a computer model-based study by US and Swedish scientists, sex-specific epigenetic “markers” on DNA (environmentally influenced chemical “markers” which alter gene activity without affecting the genetic code itself) which do not usually pass from parent to child (and are thus “erased”) can lead to homosexuality when they escape erasure and are transmitted from father to daughter or from mother to son.

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 Professor Rob Brooks is Professor of Evolutionary Biology of the University of New South Wales

 “There are no end of theories for the biological basis of homosexuality, but none of them provide a convincing fit to all the data. The new idea, that epi-genetic marks used by the genome to manage sexual development may be responsible makes a lot of intuitive sense. It provides a “genetic basis” for homosexuality without requiring that there be “genes for” homosexuality. It’s more than a theory of homosexuality’s origins, though. It also adds to our understanding of how sex-differences might arise.

 “This idea needs testing and modification. But it provides a breathtaking example of how the newish science of epigenetics is transforming our understanding of evolution and human nature.”


*Homosexuality as a consequence of epigenetically canalized sexual development, Rice, W. et al., Quarterly Review of Biology, 87(4), 2012