In Article <31A4CCDA.1A9A at pharma.unizh.ch>, krishna at pharma.unizh.ch (ram) wrote:
>Hi,
>>Can anyone tell me about the approximate time when the mice mate.
>According to the Hogan's "manipulating the mice embryo", the mice mate
>approx. at midnight. But I am noticing quite a lot've variation in the
>mating time for the 129 Sv mice strain. Are there other's who are
>facing similar problems?
You don't say how you are assessing the variation. There is natural
variation throughout the first half of gestation in the mouse and is
something you have to live with. I understand it is due to variation in
implantation times regardless of the time of mating and due to differences
in cycle times in the females. As someone who does transgenics I can attest
that when you syncronise the cycles with hormones the litters of fertilised
eggs obtained the next day are within a couple of hours of each other. You
could try this in older mice if it is bothering you but you have to
syncronise with the natural cycle.
I have always worked on the midnight assumption but I always stage the
embryos I get regardless of what stage they *should* be at.
Peter
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Peter Ashby National Institute for Medical Research
Eukaryotic Molecular Genetics London, England
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