Varieties of Rats/Genetics

The following tables show varieties of fancy rats... The genetic and descriptive information on this page is correct to the best of my knowledge. If you spot any errors, or have any suggestions please feel free to email maplewoodrattery@hotmail.com. Any input is appreciated.

A hyphen ( - ) has been used, to indicate where a recessive gene (allele) may be present. The recessive gene (allele) will not change the physical appearance. Only the dominant gene (represented by a capital letter) is visible in the physical appearance (phenotype) of the rat. In order for a recessive gene to show it must be homozygous meaning that it occupies both loci.

For example: Two black rats may have the same phenotype, or physical appearance. However, one rat may be a homozygous black (a/a B/B C/-) meaning that the "B" gene will occupy both loci. The other rat may also be black (a/a B/b C/-) but the "b" allele will occupy the corresponding locus. The characteristics of the "b" allele will not show because the "B" allele is dominant.This rat is heterozygous. Therefore, two rats may have the same phenotype, but different genotypes.

Variety	Locus	Description
Dumbo	du	Ears are larger and rounded, set lower on the head.
Hairless	hr, fz, nu	Depending on the gene responsible for the hairlessness, there may be a complete absence of hair, a few thin fuzzy hairs, or a patchy bald appearance. If whiskers are present, they shoud be curled, kinked, or bent. Skin should be pink for show varieties, but there are hairless rats with dark skin and a very new variety with markings that resemble that of chinese hairless dogs w/ spots. The hairless genes affect the milk glands so most females will not be able to nurse. Hairlessness is also a result of a the rexing gene in homozygous form, better known as "double-rex". I still have not found a gene responcible for my velour rats.
Velour	unknown	Rats have curled whiskers, and very thin, soft, wavy down-like hair. The lighter varieties appear hairless from a distance. Possible double rex.
Rex	Cu1, Cu2, Re, Sh, k, wv	Hairs are curled/waved including whiskers. Few to no guard hairs. The degree of curl will depend on the gene. (Cu1, Cu2, Re, and Sh are dominant traits) Some rexing genes in homozygous form (also known as "double-rex") will cause hairlessness.
Standard		Coat should be thick, glossy, smooth and sleek.
Satin	unknown	Coat is thinner and longer, hair shaft has a transparent outer layer causing an obvious satin sheen.
Tailless	Tal	Tail is absent. Depending on the degree of taillessness (absence of vertibrae) hip problems may occur . Females may have difficulty birthing due to the lack of strength in the hindquarters.
Jumbo	fa	Zuckers rats are jumbo genetically. Not all large rats are Zuckers though, but it is one gene that will cause large diabetic rats.

*These markings are often phenotypical, not genotypical. A variety of genotypes can create blazing, masked, notched, etc. (ie: a masked rat rat may be the result of recessive head spotting, or perhaps dominant white spotting)

Name	Genotype	Description
Bareback	h<b>/h	Color covers the head, neck and shoulders. The rest of the body should be completely white.
Berkshire	H/h	As much white on the chest and belly as possible (not to extend up the sides of the body). Feet white. White spot on forehead is very desirable.
Blaze	*unknown	A blaze of white running from the muzzle to the ears including the whisker beds, tapering to a fine point between the ears. Resembles badger markings. Shown only in Berkshire or Variegated.
Broken	h'/h' (?)	A few large spots evenly dispersed on the head and/or body.
Capped	h'/h	Color on head should follow the jaw line, but not extend past the chin and ears. A white spot on the forehead is desirable. The rest of the body should be completely white.
Cap-Stripe	*unknown	Following the cap, there is a line extending down the spine, but not joining the cap at the neckline. (Similar to a hooded but the hood breaks at the neckline.)
Dalmation	*unknown	Body is white w/ eveny dispersed small spotting.
Hooded	h/h	Hood should cover the head, neck, chest and shoulders. The hood should extend down the spine to the tail.
Husky	C-kit	The gene causes facial markings and a thick dorsal stripe. The face is to be blazed, the color should cover the eyes ears and extend down the back and sides to the tail. Markings similar to a husky dog.
Irish	H/h<i>	White triangle centered on chest, not to extend onto forelegs. Feet are white.
Masked	h'/h' (?)	Color covers only the face from eye to eye, not to extend past ears. (mask resembles Zorro's)
Notched/Capped	h<n>/h	Color on head should follow the jaw line, but not extend past the chin and ears. A white notch on the forehead. The rest of the body should be completely white.
Variegated	H/h'	Head and shoulders are colored. White blaze on forehead. The variegation of color should extend from the shoulders to the tail. Not to be marked on the belly.
Black Eyed White	h<n>/h<n> or, W/W	Coat is to be all white. The white is not related to albanism however. The BEW is actually a marked rat with so few markings that only the eyes retain black pigment. Masked rats also fall under this catagory of BEW.

Entire body is the same color, but the coat consists of individual hairs banded with two or more colors (usually yellow tones), evenly interspersed with colored guard hairs.

Color	Genotype	Description
Agouti,Wild	A/- B/- C/-	Rich ruddy brown, evenly ticked w/ black guard hairs. Base fur dark greyish-black. Belly fur to be silver grey. Eyes black.
Agouti, Russian Blue	A/- B/- C/- d/d	Dark slate blue, evenly ticked w/ black guard hairs. Base fur dark grey. Belly fur as in Agouti. Eyes black.
Agouti, Blue ( aka Opal)	A/- B/- C/- g/g	Light greyish blue, evenly ticked w/ black guard hairs. Base fur grey. Belly as in Agouti but of a lighter shade. Eyes black.
Agouti, Golden (aka Cinnamon or Mink Agouti)	A/- B/- C/- m/m	Warm golden brown, evenly ticked with chocolate guard hairs. Base fur mid-grey. Belly fur as in Agouti but of a lighter shade. Eyes black.
Amber	A/- B/- C/- p/p	Brassy blonde, evenly ticked w/ brown guard hairs. Base fur is pale grey. Belly ia also pale. Eyes are pink.
Cinnamon Pearl (aka Pearled Mink Agouti)	A/- B/- C/- m/m Pe/pe	Coat has (3) bands of color. From the base up - cream, blue and orange with silver guard hairs. Coat has overall golden apppearance w/ silver sheen. Belly fur is pale grey. Eyes black.
Chinchilla	(unknown)	Silver grey with medium slate at the base of the hair. Coat is evenly ticked with black guard hairs. Eyes are black.
Fawn (aka Topaz)	A/- B/- C/- r/r	(Agouti dilluted by red eye.) Golden fawn, evenly ticked w/ brown guard hairs. Belly is pale grey. Eyes red.
Lynx	A(?)/- B/- C/- (r/r)	Dark Agouti w/ red-eye dilute? Modifiers unknown.

Color	Genotype	Description
Albino	--c/c--	Void of any pigment, fur is white, skin is pink, eyes are pink.
Beige (aka Buff)	a/a B/- C/- r/r	Coat is a peachy cream, no greyness. Belly is the same color. dark ruby eyes.
Black	a/a B/- C/-	Coat is solid black, may be some silvering to various degrees. Eyes are black.
Blue or American Blue	a/a B/- C/- g/g	Coat is a medium slate blue. Eyes are black.
Blue, Russian	a/a B/- C/- d/d	Coat is a dark slate blue. Eyes are black.
Blue Beige	a/a B/- C/- d/d r/r or, a/a b/b C/- d/d r/r?	Coat is light blue w/ beige tinge. Red eyes.
Brown (aka Chocolate)	a/a b/b C/-	Coat is chocolate brown. Eyes black.
Champagne	a/a B/- C/- p/p	Warm blonde, lighter than beige, no greyness. Pink eyes.
Coffee	a/a b/b C/- (r/r)? or a/a b/b C/- f/f	Light coffee with cream color. Unknown modifiers. Eyes ruby or black. Possible that Coffee is the red eye dilute of Brown, or maybe linked to the Fawn gene. If (f/f ) causes Brown to be diluted to a coffee color. Possible that (d/d or g/g) also dilutes brown to coffee?
Lilac	a/a B/- C/- m/m r/r ? or a/a B/- C/- d/d m/m?	Medium dove grey mixed with brown. Eyes are dark ruby or black. This color may be achieved by mixing russian blue (d/d) with mink (m/m), or mink with red eye dilute? More information needed.
Mink (aka Dove)	a/a B/- C/- m/m	Brownish grey with a definate blue cast, no silvering. Eyes black.
Pearl	a/a B/- C/- m/m Pe/pe	palest silver, cream undercoat, each hair is delicately ticked with grey. Eyes are black.
Powder Blue	a/a B/- C/- g/g m/m or a/a B/- C/- g/g f/f	Minked Blue? I need more information on this one. I have my own theory through breedings and I suspect that as in Coffee, the fawn (f) gene dilutes blue to lavendar or powder blue.
Platinum	a/a B/- C/- g/g r/r	Standard blue with red eye dilute.Coat is a very light blueish grey. Eyes are red.
Silver	a/a B/- C/- g/g p/p	Coat is a very light icey blue, eyes are pink.

Silvering may occur in any color. The coat should contain an even number of silver and non-silver hairs. Each silver hair should be white with only a slightly colored tip. Silvering gives and overall sparkling appearance.

Color	Genotype	Description
Silver Black	a/a B/- C/- s/s	Very dark charcoal, evenly ticked with silver hairs. Eyes black
Silver Chocolate/Brown	a/a b/b C/- s/s	Deep rich brown, the coat should contain and equal amount of silvered and non-silvered hairs. Eyes black.
Silver Fawn	A/- B/- C/- r/r s/s	Rich orange, evenly ticked with silver hairs. Belly is to be white. Eyes red.
Silver Lilac	a/a B/- C/- m/m r/r s/s	Medium dove grey mixed with brown, evenly ticked with silver hairs throughout. Eyes ruby or black.(Possibly mink with red eye dilute or, unknown modifiers)
Silver Mink	a/a B/- C/- m/m s/s	Greyish brown with a blue sheen. The coat should contain an even number of silver and non-silver hairs. Each silver hair should be white with only a slightly colored tip. Eyes black.

Himalayan & Siamese develop the shaded areas at the 6 coolest parts of the body: Nose, Ears, Fore Legs, Hind Legs, Tail, and Feet.

Name	Genotype	Description
Himalayan	a/a B/- c(h)/c	Body color is white, nose, ears, feet and tail are to be a dark sepia. Eyes are red.
Merle(aka Inkspots)	(unknown)	Merle rats may be any color. Dark splash-spots are distributed throughout the entire lighter background color so as to resemble a merle dog. Eye color to correspond to the body color. (Differs from dalmation in that base color is not white.)
Siamese, blue point.	a/a B/- c(h)/c(h) g/g	Body color is cream/beige. Blue shading should reach full intensity at the hindquarters, feet, and nose. Eyes are ruby red.
Siamese, seal point.	a/a B/- c(h)/c(h)	Body color is cream/beige. Dark brown shading should reach full intensity at the hindquarters, feet, and nose. Eyes are ruby red.
Siamese, mink point.	a/a B/- c(h)/c(h) m/m	Body color is cream/beige. Mink shading should reach full intensity at the hindquarters, feet, and nose. Eyes are ruby red.
Smoked	i/i	Smoking refers to the base coat being noticably white (usually half way up the hair shaft) occurring most often in mink, lilac, and blue rats.

These rats may theoretically occur in any color, however they will most likely occur in diluted colors such as Fawn, Amber and Champagne.