Researchers have shown for the first time that introduction ofthe mouse sex-determination gene Sry into female mouseembryos causes the embryos to develop into males.
This experiment, reported in today's issue of Nature,apparently proves that Sry, the sex-determining region on theY chromosome, is the same gene as the long sought after testis-determining gene (Tdy) responsible for triggering maledevelopment.
The same research team, led by Robin Lovell-Badge at the MRCNational Institute for Medical Research in London, last yearcloned the mouse Sry and human Sry genes, and showed thatmales lacking such genes do not develop a testis and havefemale characteristics.
Although Sry appears to be sufficient to trigger maledevelopment, only three of 11 Sry-containing female micedeveloped as males. The authors speculate that the Sry genemay have integrated in regions of the mouse DNA thatprevented expression of the gene.
The scientists also introduced the human Sry gene into miceand isolated three Sry-expressing transgenic female mice. Noneof the mice developed into males. The authors hypothesize thatthe Sry protein may not be similar enough to Sry to work inmice.
-- Carol Talkington Verser, Ph.D. Special to BioWorld
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