Colors, Loci, and Basic Expression
Just like everything about an organism, a rat's color is controlled by genetics. Our basic colors are mostly controlled by recessive genes. This means that 'most' of our colors cannot express unless a copy of that gene is inherited from each parent. Those RECESSIVE traits are noted with lower case letters of that locus. (A copy of Russian Blue, if present, is written as 'd'; If not present is is written as 'D'.)
If you consider a rats base color like a blank canvas, each dilute (Dilute - a gene whose expression modifies the base color) acts like a layer of paint. Our two base colors are Agouti (A/) and Black (aa). These are the canvases that we will paint. In this blog post, I will only touch on single simple dilutes...
Agouti Locus 'A'
Agouti - The genotype for agouti is A/. The slash means that either a capital or lower case letter can fill that space. Agouti is dominant, and is also the "wild" rat color. This gene creates banding on the hairs. The tips of the hair display a yellow to brown tone tone in varying shades with a gray toned shaft and black guard hairs (Guard hairs are the long, individual hairs that protrude beyond the length of the rest of the coat). If you have a rat with the genotype AA or Aa, that rat will be Agouti as its base color before you calculate in any dilutes.
Agouti English Irish Dumbo - Reeces
Black - The genotype for black is aa. That means that there is NO agouti present. Since this color is able to be seen only with no Capital 'A' (Agouti) present, that means that Black is recessive to Agouti. Black is the solid color base, meaning that it does not have the same banding as is present in Agouti. This also means that if any dilutes are added to this Black base, they will not have banding either.
Brown Locus 'B'
Chocolate - This is a simple recessive color. This is not a common color and most rats that people see and believe is this color turn out to be very poor blacks who carry a single copy of multiple color genes. There is however a few U.S. Ratteries who have very good strong lines of chocolates. This color should be an even rich dark chocolatey brown tone. It should be even and not rusted. These are of course ideals. *I have no photos that are my own that include a Chocolate rat*
Albino Locus 'C'
This is a much more complicated gene, and can be a full blog entry all in itself. Suffice it to say today, that it is present.
Dilute Locus 'D'
Russian Blue - Another recessive gene. This color is a deeper medium blue gray. There is a speckling or ticking found in this blue (also known as heathering). There are frequently darker guard hairs also seen on these guys. Also unlike American blues, Russian blues have a dark under belly, very close in color to the top.In the UK and Australia this gene is in the 'RB' locus.
Gray Locus 'G'
American Blue - This gene is a simple recessive gene. This means that, if a baby only gets one copy, they can not express this color. In order for this to be expressed, or see, they must have the genotype of 'gg'. This color is ideally a varying shade of blue, between deep blue and a pale blue, with a lighter more silvery base coat and lighter underbelly. *Please Note: In the UK and Australia the same color is represented under the the 'D' locus. *
This will conclude this blog post because, for some, this may be a bit to absorb. Next post will include Mink, and most of the variations in the albino locus. ENJOY!
*These Photo's are mine, of my rats, and may not be used without my permission except for educational purposes.* I apologize for the poor photo quality. I will be investing in an updated camera and a light box soon.
Black Banded Berkshire - Kitten
Brown Locus 'B'
Chocolate - This is a simple recessive color. This is not a common color and most rats that people see and believe is this color turn out to be very poor blacks who carry a single copy of multiple color genes. There is however a few U.S. Ratteries who have very good strong lines of chocolates. This color should be an even rich dark chocolatey brown tone. It should be even and not rusted. These are of course ideals. *I have no photos that are my own that include a Chocolate rat*
Albino Locus 'C'
This is a much more complicated gene, and can be a full blog entry all in itself. Suffice it to say today, that it is present.
Dilute Locus 'D'
Russian Blue - Another recessive gene. This color is a deeper medium blue gray. There is a speckling or ticking found in this blue (also known as heathering). There are frequently darker guard hairs also seen on these guys. Also unlike American blues, Russian blues have a dark under belly, very close in color to the top.In the UK and Australia this gene is in the 'RB' locus.
Russian Blue Mismarked Berkshire - Zero
Gray Locus 'G'
American Blue - This gene is a simple recessive gene. This means that, if a baby only gets one copy, they can not express this color. In order for this to be expressed, or see, they must have the genotype of 'gg'. This color is ideally a varying shade of blue, between deep blue and a pale blue, with a lighter more silvery base coat and lighter underbelly. *Please Note: In the UK and Australia the same color is represented under the the 'D' locus. *
American Blue Irish - Bella
This will conclude this blog post because, for some, this may be a bit to absorb. Next post will include Mink, and most of the variations in the albino locus. ENJOY!
*These Photo's are mine, of my rats, and may not be used without my permission except for educational purposes.* I apologize for the poor photo quality. I will be investing in an updated camera and a light box soon.
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