Rabbit Genetics: The A Locus

There are 3 genes in the A locus. The most dominant is "A", the second dominant is "a(t)", and the most recessive is "a".

~ Agouti
"A" is called the Agouti gene. All agouti colors have to carry at least one of these genes. If they carry two of these genes then they are homozygous (pure) for the agouti gene. Meaning they can not produce any other color except an agouti color. The agouti gene creates different bands of color in the hairshaft. It also creates the agouti markings (such as the white bellies, white inside of the ears, white lacing around the nostrils, etc). For example, a chestnut agouti (castor) has a white belly. It also has 3 colors in the hair (top layer: black, intermediate layer: red/orange, and bottom layer [undercolor]: slate blue). The following colors are some of the colors that are agouti colors:

Chestnut Agouti, Castor, Sandy Gray, Copper, Gray, Opal, Chocolate Chestnut Agouti, Chocolate Agouti, Cinnamon, Lynx, Red, Fawn, Cream, Orange, Chinchilla (black, blue, chocolate, lilac, sable, and smoke pearl), Squirrel, Tri Color, Harlequin, and all Steels (silver tipped & gold tipped, black, blue, chocolate, lilac, sable, and smoke pearl).

*A correct tri color or harlequin are agouti colors. The orange/red, fawn/cream that is seen is created by the agouti gene. When the spots that the orange/red/fawn/cream color should be are a tort color it is a self tri color/harlequin (a non-agouti based color).

The Agouti gene can also carry tan pattern and non-agouti. When the agouti gene carries tan pattern or non-agouti it is heterozygous. Meaning it is not pure for the agouti gene.

~ Tan Pattern
"a(t)" is called the Tan Pattern gene. All Tan Pattern animals have to have at least one tan pattern gene. If it has two tan pattern genes then it is homozygous for the tan pattern. The tan pattern creates the gold ticking that is seen otters. It also creates the silver ticking that is seen in silver martens. It creates the silver ticking when it is paired with the chinchilla or shaded gene. The following colors are some of the colors that have the tan pattern gene:

Tan (black, blue, chocolate, and lilac), Otter (black, blue, chocolate, and lilac), Silver Marten (black, blue, chocolate, lilac, sable, and smoke pearl), Tortoise Marten (black, blue, chocolate, and lilac), Fox (black, blue, chocolate, and lilac).

The tan pattern gene can also carry non-agouti. When the tan pattern gene carries non-agouti it is heterozygous. Meaning it is not pure for the tan pattern gene.

~ Self (Non-Agouti)
"a" is called the Non-Agouti or Self gene. All self varieties have to carry two non-agouti genes. They are automatically homozygous for non-agouti. They have to be homozygous for non-agouti because it is the most recessive gene in the A Series and a recessive gene cannot carry a gene that is dominant to it. The self gene makes the animal look all the same (unless it is paired with another gene [I.e. the shaded gene creates shading]). They do not have agouti markings (white belly, etc) like agouti colors do. Their under color is a bit lighter. For example the undercolor on a black is slate blue and the undercolor on a chocolate is dove gray. The following colors are some of the non-agouti colors:

Black, Blue, Chocolate, Lilac, Tortoise (black, blue, chocolate, and lilac), Siamese Sable (Sable), Seal, Smoke Pearl, and Sable Point.

Rabbit Genetics | Genetic Terminology | A Locus | B Locus | C Locus | D Locus | E Locus | Vienna & Broken Loci