Gene findings may explain how the two sexes evolved
FRIDAY, Jan. 11 (HealthDay News) -- One of the oldest known types of fungus seems to contain clues to gender development in humans.
Duke University researchers report on the unusual linkage in the Jan. 10 issue of Nature.
In research with Phycomyces blakesleeanus, the Duke team isolated two versions of a gene that regulates mating. They named these versions sexM (sex minus) and sexP (sex plus). Both encode for a single protein called a high mobility group (HMG)-domain protein that leads to sex differentiation through an unknown process.
This protein is similar to the one encoded by the human Y chromosome, called SRY. When SRY is turned on, a developing fetus develops male characteristics.
The similarity suggests HMG-domain proteins may mark the evolutionary beginnings of sex determination in fungi and humans, said research team leader Dr. Joseph Heitman.
He and his colleagues propose that sexM and sexP were once the same gene that went through a mutation process, which resulted in the evolution of the two separate sex genes. The same process may be responsible for the evolution of the male Y chromosome in humans, Heitman said.
In the next phase of this research, he hopes to identify the sex region in another type of fungus.
"Fungi are good model systems for the evolution of human sexual differentiation because the genetic sequences responsible for sex are smaller versions of chromosomal sex-determining regions in people," Heitman said in a prepared statement.
To learn more about Duke University research, visit its Medical Center and Health System News Office .
-- Robert Preidt
SOURCE: Duke University, news release, Jan. 9, 2008
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