Mouse Coat Color Calculator

Mouse coat color is determined by a set of interacting Mendelian gene loci. Each locus has a dominant and a recessive allele; the combination of alleles across all loci — together with epistatic interactions — produces the final visible phenotype. This calculator models the five classical loci:

The albino locus (C) is epistatic to all other pigment loci: a mouse that is homozygous recessive (cc) cannot produce any pigment, appearing white with red eyes regardless of its A, B, D, or P genotype. Similarly, the dilute (D) and pink-eyed (P) loci both reduce pigment intensity but through distinct mechanisms — dilute affects pigment granule distribution (producing blue or lilac coats), while pink-eyed dilution additionally affects eye color.

1. Set Parent 1's genotype — for each of the five loci, choose whether the parent is homozygous dominant, heterozygous, or homozygous recessive. The genotype string (e.g. AaBbCCDDPP) updates live below the selects.
2. Set Parent 2's genotype — repeat for the second parent. You can model any combination: purebred × carrier, two carriers, outcross, and so on.
3. Read the distribution table — the calculator enumerates all 2⁵ possible offspring genotype combinations, applies epistasis rules, and groups the results by phenotype. Each row shows the expected percentage of pups with that coat color.
4. Share or export — use the Share URL button to copy a link that encodes both parent genotypes, or export the distribution as a CSV file.
5. Track in Moustra — for ongoing colony management, record individual animal genotypes, track coat-color inheritance across generations, and plan future crosses directly in Moustra.