# Umbrous: a case of dominance modification in mice



## Jack Garcia (Oct 9, 2009)

A couple weeks ago I posted pictures of a dark agouti female I got from a friend, who got her stock in The Netherlands.

Since I breed agouti as my main variety, it's particularly interesting to me as to what makes a mouse so dark. It turns out that is a phenotype of agouti mice called intermediate agouti, which is "in between" full agouti (A/*) and non-agouti (a/a) when umbrous is present, which can present as a thick black stripe down the back of an agouti mouse. With PE dilution, this would present as a dove stripe down the back of an argente mouse (I have a mouse like this).

Here is the preview of the article I found, which describes the phenomenon exactly: http://www.springerlink.com/content/x3l42618rp178607/

I have membership to a university library and have asked them for a full print-out copy of the article.

Edit: found the full article online, though it's poorly scanned (or poorly printed!) here: http://www.ias.ac.in/jarch/jgenet/40/229.pdf


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## moustress (Sep 25, 2009)

That makes a lot of sense; I felt sure there had to be something other than plain agouti going on genetically.


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## Jack Garcia (Oct 9, 2009)

Here are some pictures. It's hard to get pictures that show the difference in color...




























Those are all with different lighting levels. The grey you see on her back is not a camera effect; it's actually there. There is 0 ticking in that area, as it has reverted back to non-agouti.


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## moustress (Sep 25, 2009)

Very interesting. Nice mousie too. I love red-eyed dilutes.


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## Jack Garcia (Oct 9, 2009)

Thanks. I wish I could "get rid of" all the PE in my agouti mice, but it doesn't seem like that's gonna happen! 

Two of the animals out of my foundation stock had/have PE, and one carried it unbeknownst to me.


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