# Getting the mix right



## tiffanyjayne (Mar 9, 2013)

i've recently had 2 litters

3x PEW rex's off a chocolate rex pair.......and 3 normal chocolates off a black rex and normal broken black/white

I've never bred a mouse before so this was odd and not at all like mixing paint  when I get to breeding the mice i'd like to keep i'll be sure to check backgrounds so it's not so confusing


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## TwitchingWhiskers (Feb 2, 2013)

The first pairing: both parents carried albino (C/c), and each parent gave a copy to the offspring making them c/c. Albino acts like white paint, and covers up what the mouse is under the paint, which we call masking what the color the mouse really is under that white paint. All three of your PEW's must be masking chocolate (a recessive gene), because for the parents to show chocolate, they have to both be b/b, and can only contribute b on the b locus. Astrex is dominant, so the parents are either Re/Re, or Re/*, and the babies each have one or two copies as well. It can be hard with dominant genes to figure out if they are heterozygous or homozygous, but it shouldn't matter too much right now. 

Second litter: both parents must be carrying chocolate making them both B/b, and each must have given each baby one copy making the babies b/b. If your mouse is rex, some of the babies should be rex as it is a dominant gene... did you cull the litters down? If not it could be just bad luck. "Broken" marked mice are selectively bred to have spots in certain places, your mouse is likely piebald. Piebald is recessive, so the black piebald parent is s/s, which would make all of the offspring S/s (piebald carriers).

What colors and coats are you breeding for? Yes, genetics are definitely not as simple as mixing paint, I wish they were though.


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