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Fancy Rat Colors, Patterns, & Coat Types

Finding examples of gene combinations can be challenging - below are some examples showing phenotype/genotype across different traits.


The color terms I use don't always match what AFRMA (or other clubs) recognize, mostly because what they recognize are limited to certain standards and don't always inform on the genotype of the animal. For those of us who aren't hard-core show rat people, it's a lot more valuable to be able to look at a rat and understand what genes are at work are making it look the way it does. I've attempted to include commonly accepted genotype codes when possible.


[this post is in progress, draft posted 9/7/22]

For example - what is this rat? It's a BEW (black eyed white), but why? Is it a result of c dilutes? Is it a fully-marked rat where essentially the entire body is covered in a white marking?

Body Type

Specific genes that alter the size/shape/form of a rat, regardless of what their fur looks like.


"Show type" rats are selectively bred for particular traits closest to a defined standard - these can be things like overall body shape, head shape, the way the tail tapers from the body, etc.

​Standard - normal size, normal ears, normal tail, etc.



Dumbo - Ears placed low to the sides of the head.

Recessive [du/du]



​Dwarf - Adults are only about 1/3rd the size of standard adults.

Recessive []

Tailless / Manx - Partial or missing tail.

"Complicated" Recessive [multiple genes]

Coat Types

These genes impact the texture, length, or structure of the hairs. Are the hairs straight or curly? Are they "hollow" inside like a polar bear's? Do the hair follicles function normally? Coat types CAN impact color, but are more to do with hair structure than the pigments present.

Standard



Rex

Dominant, heterozygous: [Re/re]

Double Rex

Dominant, homozygous: [Re/Re]


Double rex can look practically hairless, or have thin, patchy/fuzzy hair.



Hairless

Recessive [hr/hr]



Velveteen

Dominant [V?/*]

Silvermane / D'Argent - Ends of the hair shafts are hollow/translucent, causing a silvering effect that matures in the adult coat.

Dominant [Sm/*]


(See what silvermane looks like on different colors here!)




Harley - Longer, wispy/thin hair.

Recessive [l/l] (lowercase Ls)

Patchwork / Werewolf

Recessive []

Satin

Recessive [sa/sa?]


(not very common in US outside of show breeders)

Patterns

Patterns and markings are areas where pigments are inhibited (or enhanced) in particular areas. Most patterns and markings are in the form of white (no pigment) patches. Very often there are multiple markings that all arise from selectively breeding one gene but for different presentation. The "Hooded" gene is responsible for hooded rats, berkshire rats, irish rats, whiteside rats, etc. Patterns are separate from whatever "color" a rat is at its base. For example, a cinnamon rat can also be albino - which would cover up all evidence of the underlying color.

Standard (Self) - No markings or patterns at all.

​Hooded - Highly variable and VERY common / widely distributed.

Dominant: [H/*]

> Berkshire

> Irish

> Capped

> Blaze

> Downunder

> Whiteside

Albino

Recessive [c/c]



Himalayan

Recessive [c^h/c]



Siamese

Recessive [c^h/c^h]

Black Eyed

Dominant [Be/*]



Roan / Husky

Merle

Marble / Spotted Tabby

Dalmatian

Homozygous Lethal

Colors

Each gene impacting color will look different depending on whether it's acting on a banded (agouti) hair or solid (black) hair - and generally people will call colors different names depending on which A locus base (agouti or black) they're added to.

Naming colors in rats is a mess. It varies depending on what country you're in, what part of what country, what breeder you're talking to, etc... if you're confused, don't worry, everyone calls everything something different.

​Agouti (A/A or A/a) Base

Black (a/a) Base

No other presenting colors


May carry mink, blue, ruby eye, etc.

Agouti



Black



Add mink [m/m]

Cinnamon


Mink


Add blue [g/g]

Blue Agouti


Blue



Add ruby eye [r/r]

​Fawn

​Beige

Add pink eye [p/p]

​Silver Fawn

Champagne

Add mink + blue [m/m g/g]

Lynx


Platinum, (Lilac)


Add ruby eye + mink [r/r m/m]

Havana?

Add blue + ruby eye [g/g r/r]

Add blue + pink eye [g/g p/p]

Silver

Add Russian blue [d/d]

Add chocolate

(not very common in US outside of show breeders)


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