Updated: Feb. 19 (2024)
Siamese
Siamese, ch/ch
Two copies of Himalayan
Chromosome: 1
RVG description:
Body color will start out warm beige and should start shading around 2-3 weeks. The pigment will start to only be produced on the extremities (nose, ear, feet, and tailbase). The body will eventually be left off-white and the points will have a nice brown color. Eyes pink to ruby.
Extra information:
The Himalayan gene was derived from a "fatty" line and there could still be weight issues with rats processing the chch or chc genotype.
The ch allele, dominant to its recessive counterpart; c, is a temperature-sensitive allele that has influence on melanin production. Unlike the c allele, which in its homozygous form leads to albinism (complete absence of pigment), the ch allele only partially inhibits pigment production, resulting in a distinct development of pigment across the body.
The ch allele will activate pigment production when the skin is exposed. During initial fur development, the skin is bare which signals pigment production across the entire body, giving rise to a warm beige fur color. As the coat grows and sheds the signal is gradually turned off due to the skin being insulated by a thick coat and the color will start to progressively lighten in the warmest regions. The coldest regions will continue to produce pigment because more skin is exposed in these regions thus creation the famous points.
Shaving any body region disrupts thermal regulation, triggering pigment production in the shaved area. This darkening remains localized until the entire coat sheds, which can take several months.
Sources:
Two copies of Himalayan
Chromosome: 1
RVG description:
Body color will start out warm beige and should start shading around 2-3 weeks. The pigment will start to only be produced on the extremities (nose, ear, feet, and tailbase). The body will eventually be left off-white and the points will have a nice brown color. Eyes pink to ruby.
Extra information:
The Himalayan gene was derived from a "fatty" line and there could still be weight issues with rats processing the chch or chc genotype.
The ch allele, dominant to its recessive counterpart; c, is a temperature-sensitive allele that has influence on melanin production. Unlike the c allele, which in its homozygous form leads to albinism (complete absence of pigment), the ch allele only partially inhibits pigment production, resulting in a distinct development of pigment across the body.
The ch allele will activate pigment production when the skin is exposed. During initial fur development, the skin is bare which signals pigment production across the entire body, giving rise to a warm beige fur color. As the coat grows and sheds the signal is gradually turned off due to the skin being insulated by a thick coat and the color will start to progressively lighten in the warmest regions. The coldest regions will continue to produce pigment because more skin is exposed in these regions thus creation the famous points.
Shaving any body region disrupts thermal regulation, triggering pigment production in the shaved area. This darkening remains localized until the entire coat sheds, which can take several months.
Sources:
- Himalayan allele at the Albino locus in the Norway Rat (note that the paper's Himalayan is what we in the fancy call Siamese)
Variations of Siamese
Russian Point Siamese, ch/ch d/d
Two copies of Himalayan and two copies of Russian Blue. *please note that the pictures pups were from a very pigmented litter and most RB Siamese will be lighter in tone, like the baby at the end. |
|
Mink Point Siamese, ch/ch m/m or ch/ch mo/mo
Two copies of Himalayan and two copies of either Mink or Mock Mink. |
|
Dove Point Siamese, ch/ch d/d m/m or mo/mo
Two copies of Himalayan, two copies of Russian Blue, and two copies of either Mink or Mock Mink. *please note that the last 3 pictures are of pups from a very pigmented litter which is not the norm. Their points as adults will look like regular points. |
|