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Genetic Alphabet: A B C D E
The basics of rabbit color genetics focus on just FIVE basic gene sets (or chromosome locations aka loci). These gene sets are sometimes called “families” and are identified as A, B, C, D, and E. Each rabbit has TWO genes in each family, called alleles. The first gene in each set is the dominant gene (the gene we see), and the second gene is the recessive gene (what we do not see). Each rabbit receives ONE gene from each parent for each set. Remember, each rabbit always gets TWO copies of each gene. They randomly get one copy from each parent. So they get two genes from the A locus, two genes from the B locus, and so on. Capitalized letters usually refer to the most dominant gene, and lowercase letters usually refer to more recessive genes.
EUMELANIN & PHEOMELANIN
The five main loci change how two fundamental pigments appear on a rabbit- black/brown (eumelanin) and yellow/red (pheomelanin). The expressed color (or the phenotype- the color you see) is a function of how much of these pigments exists in the hair. These five loci are also affected by other modifying genes. Some genes PRODUCE a color, and some genes TURN OFF a color.
The amount of pigment can change not only from hair to hair, but also along the length of a single strand of hair. In rabbits, there can be as many as FIVE bands of color on a single strand. Isn’t that crazy? In addition, there are two types of hair- “outer” guard hairs which are often stiffer, thicker, and sometimes straighter than the finer, softer “undercoat” hairs. The outer coat provides protection for the rabbit while the undercoat provides insulation.
UNKNOWN RECESSIVE GENES
If a recessive gene is unknown, then that gene can be represented by an underscore (_) or dash (-). You cannot typically just look at a rabbit for most loci and know what the recessive gene is, so using the “place marker” of an underscore or a dash can be useful. You can update these place markers through studying a pedigree and/or test-breeding to determine the recessive genes that a rabbit carries.
THE RABBIT ALPHABET
There are 5 genes (I’ll call them Primary Genes for now) that decide a rabbit's color, and then a whole range of other genes (I’ll call them Secondary Genes).
Primary Genes: A- Agouti B- Black C- Complete color / color density / concentration of color D- Density / dilution of color E- Extension of color (or limitation/elimination)
Secondary Genes (some of them) En- English spot (broken) W- Wideband V- Vienna (blue eyes) Du- Dutch Si- Silvering For now, we are concentrating on the “Primary Genes.”