Genetics and Appearance of the
Russian Blue Point Siamese Rat

To be a Russian Blue Point Siamese, a rat must be a non-agouti (a) with the Siamese (ch) gene from both parents, the Russian Blue (d) gene from both parents, and be a self marking (H).

This would result in a rat with the following genetic description: a/a d/d c(h)/c(h) H/H

The Agouti Gene – The agouti gene is a dominant gene for rats. It results in a “ticked” or banded color along the hairs of the coat. A Siamese should not have the agouti gene. In a Siamese rat, the agouti gene would wash out and dilute the dark points and shading of the rat.

The Russian Blue Gene – The Russian blue gene is a recessive color. For the rat to show that it is Russian blue, it must inherit the Russian blue gene from both parents. The gene is also a color dilute. That means that on a black rat, this gene dilutes the color pigment so that the black appears to be a dark gray-blue.

The Siamese Gene – The Siamese gene can be complex at times. It is a recessive gene; so it must be inherited from both parents. The Siamese gene is actually a modifier of the albino gene. The Siamese coat is referred to as a color pattern rather than a color or a marking. This is because the rat can be any color “underneath” the Siamese color pattern overlay. The color then would only peek through at the points of its face, ears, feet, and hind end.

The Self Gene – In a Siamese rat, it is often assumed that the rat is a “self” rat. Self refers to a type of marking that is actually a lack of any marking. The rat should have the same consistent color all over its body. Any white markings on the rat are considered a fault. If a Siamese rat were to have any white markings upon its feet or face, these markings would display as a void in the dark shading which is considered by most to be very undesirable. A void in the shading would only detract from the unique contrast that is desirable in a Siamese rat.

Head - Should be evenly proportioned, with clean lines and a well-defined stop at the brow. The muzzle should be of good breadth, rounded and blunt, not narrow or pointed. The male head should project broadness and strength, while a female's projects strength and definition that is clearly feminine.
Faults: Long face with pointed muzzle, head too narrow or too wide, no clear brow stop, male head appearing too feminine, female head having a masculine appearance.

Standard Ears - Well-formed oval shape of medium size, they should be upright and spaced well apart.
Faults: Creases or folds, ears set too low or too far apart.

Standard Tail - Long and cylindrical, thick at the base and tapering to a fine point. Should be at least the length of the body (nose to base of tail) and be firm, and of size/thickness appropriate to the size of the rat, so as to give a balance appearance.
Faults: Not cylindrical, short, thin.
Disqualification: Kinked or docked.

Eyes - Large, round, and bold; set wide apart so as to give the appearance of width to the head. Placement is ideally half way between the tip of the nose and the back of the ears.
Faults: Eyes too small.

Teeth - Two upper and two lower incisors, none misshapen or missing. Mouth should be able to close normally, with top incisors in front of the lower.

Self Marking - Rat shall be all one color displaying no markings.
Faults: White fur on body, white toes/feet

Standard Coat - Fur to be dense, even, and lustrous – should lay flat and smooth. Long guard hairs or slightly coarser fur are permissible in Males. Whiskers are long and straight. Color and markings should conform to recognized standard.

Siamese - Body color to be ivory to medium beige depending on the colorpoint variety. Color to be gradually and evenly shaded over the head, shoulders, back and belly of the rat. Points to be dark as possible - shaded evenly into the body color and located on the nose but should not extend past the eyes, on the ears but not extending past the ears, on all four feet but not extending past the legs, and the base of the tail shading up over the hindquarters.
Faults: Patchy or uneven coloration, pale or light areas
Eyes: Red to Ruby

Russian Blue Point - Points to be a distinct smokey blue-gray shaded into a bright ivory color over the rat. Light heathering is normal for this Russian Blue-based colorpoint variety. Contrast between the shaded points and the ivory color of the body to be very distinct.

We are also going to try to start getting the satin gene out of the Siamese line, and we'll be looking for thicker tails on our keepers.