Rabbit Coat Colour Genetics Calculator

Formula

How this is calculated

Rabbit coat colour is determined by several gene pairs (loci). This calculator covers the two most fundamental: the A locus (agouti/self pattern) and the B locus (black/chocolate base). At the A locus, the agouti allele (A) is dominant — rabbits with at least one A show the wild-type ticked-fur agouti pattern, while aa rabbits are self-coloured (a single uniform shade). At the B locus, the black allele (B) is dominant over the chocolate allele (b), which shifts all eumelanin from black to brown.

Each parent contributes one allele per locus to each offspring (Mendel's law of segregation). A homozygous parent (AA or aa) always passes the same allele; a heterozygous parent (Aa) passes each allele with 50 % probability. The calculator combines the two loci independently (Mendel's law of independent assortment), multiplying the per-locus probabilities to get four phenotype combinations: Agouti (A_, B_), Cinnamon (A_, bb), Black (aa, B_) and Chocolate (aa, bb).

This model omits the D locus (dilute/dense — blue and lilac tones), the E locus (extension — yellow/red), and the C locus (albinism). Real breeding outcomes are probabilistic; use these percentages as expectations over many litters, not a guarantee for any single kit.