Genes for Sperm Production Located

Applied Genetics News,  April, 2001  

• E-mail
• Print
• Link

Nearly half of all genes related to the earliest stages of sperm production reside not on the male sex Y chromosome as expected, but on the X chromosome, according to a study published in the April issue of Nature Genetics.

"By default, we've traditionally thought of the X chromosome as sexually neutral or as a specialist in female characteristics," says David Page, lead author on the paper and a researcher at the Whitehead Institute for Biomedical Research (9 Cambridge Ctr., Cambridge, MA 02142-1479; Tel: 617/258-5000) and Howard Hughes Medical Institute. "Our findings indicate that the X chromosome has a specialty in sperm production, much like the Y chromosome does.

Jeremy Wang, a postdoctoral fellow in the Page lab, conducted a systematic search for genes that are active exclusively in spermatagonia-sperm stem cells-in mice. The researchers found 25 genes, including 19 new ones, that were expressed exclusively in mouse sperm stem cells. Of these, only 3 were linked to the Y chromosome and 10 were linked to the X chromosome.

"This was a big surprise because if the genes had been distributed randomly in the genome, we would have expected none, or at the most a couple, of these sperm-specific genes to be X-linked," says Page.

The finding that sperm-specific genes are found on the X chromosome suggests new avenues for study. One obvious possibility is that the X chromosome plays a role in some forms of male infertility resulting from low sperm counts. Such congenital infertility could be passed by X-linked inheritance from the mother in the same way as color blindness or hemophilia.

COPYRIGHT 2001 Business Communications Company, Inc.
COPYRIGHT 2001 Gale Group