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Japan Team Succeeds in Preselecting Sex of Mice
Tokyo, Aug. 14 (Jiji Press)--A Japanese research group has found differences in mouse sperm leading to conception of male and female babies, and succeeded in preselecting the sex of the animal, according to its report published in the online edition of U.S. journal PLOS Biology on Wednesday.
Demand is high from farmers for technologies for gender preselection for livestock offspring as market values of such animals differ depending on their sex.
But it is difficult to efficiently separate sperm containing the X chromosome and that containing the Y chromosome because there is no functional difference between them, experts say. X- and Y-bearing sperm, split from the same sperm stem cell, produce female and male offspring, respectively.
The team, including Hiroshima University Prof. Masayuki Shimada, focused on the TLR7 and TLR8 receptors, which are localized to X sperm and are believed to halt the movement of the sperm if they are stimulated.
After the team mixed mouse sperm with a culture medium and an agent to stimulate the receptors in a test tube and waited for about one hour, X sperm stopped moving and precipitated while Y sperm, unaffected by the agent, rose to the upper part of the tube. Vitro fertilization using the sperm taken from the top and bottom parts of the tube produced male and female mice, respectively, both at a rate of about 80 pct.