Researchers have discovered a gene, which maintains male sex throughout life - a breakthrough that can help shed light on the origin of some human sex reversal disorders.
The research team, led by Drs. David Zarkower and Vivian Bardwell of the U of M Department of Genetics, Cell Biology and Development, found that removing an important male development gene, called Dmrt1, causes male cells in mouse testis to become female cells.
In mammals, sex chromosomes (XX in female, XY in male) determine the future sex of the animal during embryonic development by establishing whether the gonads will become testes or ovaries.
"Scientists have long assumed that once the sex determination decision is made in the embryo, it's final," Zarkower said.
"We have now discovered that when Dmrt1 is lost in mouse testes - even in adults - many male cells become female cells and the testes show signs of becoming more like ovaries."
Previous research has shown that removing a gene, called Foxl2, in ovaries caused female cells to become male cells and the ovaries to become more like testes.
According to Zarkower, the latest U of M research determines that the gonads of both sexes must actively maintain the original sex determination decision throughout the remainder of life.
"This work shows that sex determination in mammals can be surprisingly prone to change, and must be actively maintained throughout an organism's lifetime," said Dr. Susan Haynes, who oversees developmental biology grants at the National Institute of General Medical Sciences of the National Institutes of Health.
The study was recently published in the journal Nature.