[Dean's World] Dean: Sperm vs. Egg Production

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Posted by Dean:
Sperm vs. Egg Production
http://www.deanesmay.com/posts/1144222369.shtml


   Some Australian scientists are pretty sure they've figured out why
   males produce sperm and females produce eggs. And no it's not a joke,
   stop snickering.

     The cells that eventually turn into either eggs or sperm =E2 known as
     germ cells =E2 are identical in male and female embryos.

     =E2Whether a germ cell develops into an egg or a sperm depends on the
     time at which meiosis begins,=E2 Professor Koopman said.

     =E2In females, meiosis begins before birth and eggs are produced,
     whereas in males, meiosis begins after birth and the result is
     sperm.=E2

     Professor Koopman and his team found that retinoic acid, a
     derivative of Vitamin A, causes germ cells in female embryos to
     begin meiosis, leading to the production of eggs.

     They also discovered an enzyme present in male embryos that wipes
     out retinoic acid and so suppresses meiosis until after birth,
     resulting in sperm production.

   Full release [1]right here.

   They note that this new knowledge may have quite a few practical
   applications.

References

   1. http://www.uq.edu.au/news/index.html?article=3D9323