BIOGRAPHY: A key topic in the evolution of human sexuality is gender identity.
What is the biological basis of gender identity?
And how does it relate to biological sex?
In a new paper published online this week in the journal PLoS ONE, biologists at the University of California, Berkeley and Stanford University, researchers at the American Museum of Natural History and other organizations have looked into this question in detail.
The scientists were able to identify a gene that codes for a protein that codes to a hormone that affects how the hypothalamus regulates the body’s hormonal response to sex hormones.
The study also identified a gene encoding the gene for a chemical called the gonadotropin-releasing hormone receptor (GnRH) that regulates the release of the gonads from the testes.
The findings suggest that genes encoding the GnRH receptor and gonadotrophin releasing hormone receptor are critical for the regulation of human sexual behavior, said co-author John Campbell, a biologist at the UC Berkeley School of Medicine and the Howard Hughes Medical Institute.
“We’re not looking at the gene as a single molecule.
We’re looking at a family of proteins that encode a variety of different hormones and we have a very good understanding of how they interact,” said Campbell, who was not involved in the study.
“Our work is the first to identify genes involved in regulating sex hormones in mammals, and we’ve been able to do it in the laboratory.”
Campbell’s research focuses on the hormone-sensitive receptor (HSR), a gene on the surface of the immune system that controls how immune cells attack and destroy bacteria, viruses and other harmful organisms.
The researchers have found that a group of genes, including the GnH receptor, regulate the activity of the receptor, but they’ve found no evidence that the genes involved are responsible for its functioning.
The discovery opens up a new avenue for understanding human sexual physiology and behavior, Campbell said.
“The findings also open up new avenues of investigation in understanding how sexual behaviors develop, what drives them, and how genes contribute to the development of sexual behavior,” he said.
In addition to Campbell, the authors are Jia Li, Jing Feng, and Andrew S. Gao of UC Berkeley, and Yi-Yuan Zhang and Robert G. Lee of the Howard Hunt Institute for Biomedical Research in Bethesda, Md.
This research was funded by the National Institutes of Health.
Acknowledgement: This work was supported by grants from the National Science Foundation.