# Genetics help.



## fancyfeet (Dec 21, 2015)

As I'm trying to understand the genetics of mice...I was looking at the codes and colors page. Say for instance I have a Lilac and a black mouse are their codes specifically as listed and then if you breed them you could get a combination of these in the litter depending on what is passed down or can there be, for a lack of better words, hidden genes such as recessives that could show up?

For example if I get a black self mouse, is this is only code it can carry or are there others that it could pass down. aa B* C* D* P*

Black - aa B* C* D* P*
Chocolate - aa bb C* D* P*
Champagne - aa bb C* D* pp
Dove - aa B* C* D* pp
Fawn - AY B* C* D* pp
Red - AY B* C* D* P*
Blue - aa B* C* dd P*
Cream - AY* B* cchcch D* P* or pp or aa B* cce D* P* or pp
Lilac - aa bb C* dd P*
Silver - aa B* C* dd pp


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## Lilly (Nov 21, 2015)

In the genetics code the * is for unknown (but would be recessive so cannot tell unless you know lineage)

so for black

aa B* C* D* P*

a = black so for a black mouse it will always have two of those

B = brown dilution with B being none and dominant, so a black mouse can be carrying b and if bred to another carrying can end up with chocolate babies

C = c locus dilution, C being none but can carry since C is dominant, again there could be some recessive hidden under there

D = blue dilution, same as B but will make the mouse a blue color

P = Pink eye dilution where P is black eyes and p is recessive pink eyed that dilutes the coat

so a black self could be any combination of recessives in place of the * but has to have what is written to appear black

(Just as a simple thing, tan [a^t] is dominant to a and I bred a black pied tan and a blue tan together and got at least one black self so both of the mice must be a^t/a but you just cannot tell until you breed)


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## fancyfeet (Dec 21, 2015)

Hmm, ok thanks.

Quick question... So I have a long haired doe that is a dark brown, with brown eyes. Parents were both short coat selfs. She has tan behind ears but colored tail and legs with only pink feet.

From what I read on finnmouse:
The official name of brown dilution gene (allele) is "brown" and the official symbol is Tyrp1b. It turns the eumelanin of both the hairs and the eyes brown instead of black. That is, the eyes of b/b mice is not black, although they can seem to be black. In a good light and especially on photographs taken with flash, the eyes of a b/b mouse look ruby. b is fully recessive to bc.

This being said, what should I breed her with to get that rich dark chocolate color and to breed out the faults such as the light feet and ears?


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## Laigaie (Mar 7, 2011)

If you want better chocolate, you're looking for two things: black pigment and red pigment. If you have a black mouse with a better coverage of pigment on the feet, ears, tail, that can help. If you have a red/yellow/agouti/etc mouse with better warmth to the color, that can help, too. What you definitely don't want in there is blue. Blue is a recessive, and lilacs (blue plus chocolate) can be hard to distinguish from their siblings when young, leaving you with weird muddy-colored mice that don't improve anything. Using agouti or cinnamon isn't a problem, since agouti is dominant and thus easy to breed back out. Problem is, intensity and coverage of pigment are the kinds of things that aren't just one gene. Those are modifiers, meaning you'll be breeding chocolate to chocolate for generation after generation, selecting for better chocolate as you go.


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## fancyfeet (Dec 21, 2015)

Thank you so much! That answered a lot of my questions. I need warmer chocolates so the cinnamon is the direction I will go! I will definitely be posting pics! Satin Cinnamon is probably one of my favorites although I know it doesnt show well


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