Basic Color Genetics

Remember that lowercase letters represent recessives, while dominants are capitalized. Many colors arise from a combination of genes - which is part of why this list is in no way exhaustive. The C-locus is covered on another page, as is the P locus which controls pink eyes.
 

The A Locus

The alleles on this locus are listed from most dominant to least. For example, Ay is dominant or epistatic to all other alleles on the A locus while a^e is dominant to none of them.
Ay - Dominant/Lethal yellow (homozygous lethal before birth)
Avy - Viable yellow, American Brindle
A^w- White-bellied Agouti
A - Agouti
a^t - tan/fox (despite being lowercase, tan is a dominant trait needing only one copy to show itself)
a - non-agouti, black in the absence of other colors
a^e - Extreme non-agouti, Super Black, Extreme Black (possible to show through somewhat on heterozygotes).
 

The B Locus

B - non-chocolate
b - chocolate
 

The D Locus

D - non-blue
d - blue
 
Mice with the genotype bbdd are a combination of both blue and chocolate. This color is called Dove by the MMC and AFRMA in the US, and Lilac in other countries and the ECMA.
 

The E Locus

E - non-yellow
e - recessive yellow
 

The Mo Locus

Mo^br - X-linked Brindle aka Brindled aka English Brindle aka Sex-linked Brindle, generally only visible in does. Mo^br bucks will generally die within weeks of death. If they do survive, homozygous Mo^br/Mo^br does will suffer the same effects.
mo - non-brindle
 

The Rn Locus

Rn - Roan
rn - non-roan

There is a type of Roan that produces Merle (pools of color on a roan mouse) but not much is known about its inheritance. It can lie hidden in a seemingly non-roan mouse (known as "phantom merle") for generations before showing up again.
 

The Si Locus

Si - Non-silver
si - Silvered (white flecks throughout the coat)
 
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