Extension, non-extension, & everything in between!

The C locus is by far the most difficult to understand mainly because some genes are incompletely dominant over others while others are completely dominant, as well as there are more genes on this locus than the others. But, in spite of its complications, genes at the C locus are the most fascinating to work with.

The genes on the C locus controls where and how much color will be expressed rather than which color will be expressed. It is responsible for colors like chinchilla, sable, red-eyed white (albinism), and himalayan/pointed white.

There are five genes in this locus:

   C - full color
   cchd - "dark" chinchilla
   cchl - "light" chinchilla (sable)
   ch - himalayan/pointed white
   c - albino/red-eyed white (REW)

Full Color

C

The full color gene, C, is the most dominant gene within the C locus and is expressed anytime it is present. In full color rabbits, the color is not restricted to any part of the rabbit and presents normally. So, a chestnut rabbit will remain chestnut. Other genes such as non-extension, ee, may cause a shaded looked in a full color rabbit, but the color restriction is not due to the C gene in that case.

Full Color + Agouti (A)
Gold-Tipped Steel (EsE)	Chestnut (EE, Eej, Ee)	Harlequin (ejej, ej)	Orange (ee)
Full Color + Tan Pattern (at)
Black/Otter Steel (EsE)	Otter (EE, Eej, Ee)	Fox Harlequin (ejej, eje)	Fox (ee)
Full Color + Self (a)
Black (EsE)	Black (EE, Eej, Ee)	Tort Harlequin (ejej, eje)	Tortoise (ee)

"Dark" Chinchilla

cchd

The chinchilla gene or “dark” chinchilla gene , cchd, is the next dominant gene below full color, and will be expressed even if paired with any gene but the C gene. It is responsible for chinchilla rabbits (in agouti) and martens (in otters).

When the chinchilla gene is expressed, you will generally find white or pearl fur where the full color rabbit has more yellow in the fur. This is because the cchd gene causes the yellow pigment to be reduced or diluted. Once the yellow pigment is eliminated from the hair, only pearl remains. For example, an orange rabbit differs from frosted pearl only in that orange is a full color, (C), and frosted pearl expresses the chinchilla gene.

Chinchilla + Agouti (A)
Silver-Tipped Steel (EsE)	Chinchilla (EE, Eej, Ee)	Magpie (ejej, ej)	Frosted Pearl (ee)
Chinchilla + Tan Pattern (at)
Self Chinchilla/Marten Steel (EsE)	Marten (EE, Eej, Ee)	Sallander Marten Magpie (ejej, eje)	Sallander Marten (ee)
Chinchilla + Self (a)
Self Chinchilla (EsE)	Self Chinchilla (EE, Eej, Ee)	Sallander Magpie (ejej, eje)	Sallander (ee)

Please note, that when combined with the self gene, the rabbit may appear normal coat wise. However, it may “dilute” the eyes to a blue or gray color. This is known as self chinchilla.

"Light" Chinchilla - Seal & Sable

cchl

The sable or “light” chinchilla gene (cchl) we find is a slightly different situation than with the other genes within the C locus as it is incompletely dominant. With the other genes, if you pair them with a gene of a lower dominance the dominant gene will be expressed. With cchl, a homozygous pair has a different result than a heterozygous pair. Two sable genes (cchlcchl) produce a dark sepia color that is almost black, called seal.

The sable gene removes yellow from hair shafts and removes some from the darker pigments, giving the rabbit a shaded look. Again, this shaded look is different from the shaded look caused by non-extension (ee).

Pointed White / Californian / Himalayan

ch

The ch gene is responsible for the pointed white (or Californian / Himalayan dependent on the breed). These rabbits have red eyes and they develop points of darker fur on their ears, feet, and tail as they age. Pointed white rabbits are born pure white and the color starts to show up on the points between two and three weeks of age.

Himalayan + Agouti (A)
Silver-Tipped Himalayan Steel (EsE)	Agouti Himalayan (EE, Eej, Ee)	Magpie Himalayan (ejej, ej)	Frosty Himalayan (ee)
Himalayan + Tan Pattern (at)
Himalayan (EsE)	Marten Hiamalyan (EE, Eej, Ee)	Magpie Marten Himalayan (ejej, eje)	Marten Himalayan (ee)
Himalayan + Self (a)
Himalayan (EsE)	Himalayan (EE, Eej, Ee)	Magpie Himalayan (ejej, eje)	Extended Himalayan (ee)

The curiosity of the himalayan markings is that they are heat sensitive. The cooler areas of the body, which are the “points” on the rabbit, will be darker due to the decreased blood flow of those areas.

A pointed white rabbit that grew up in a cold climate will have darker points than one raised in a warmer climate. In fact, some breeders of Californians and Himalayans that live in southern regions will typically have a “chiller room” where they keep the temperature low to keep their rabbits’ points darker. The flipside is that in the northern climates, rabbits can develop smut or spots on their body over the winter while heating their building, which are disqualifications.

Albino / Red-Eyed White (REW)

c

A red-eyed white (REW) rabbit has no color at all - the rabbit will be snow white with red eyes. It is an epistatic gene, meaning that it will cover every other color on the coat. So, unless you know the rabbit’s background, a REW rabbit can carry plenty of coding for other colors.