Genetics....Briefly...
This page is not even half-way started. Please be patient.
To being with, every rat begins as either Agouti (AA) or Black (aa) in color. Dilutes are what change the color of the rat.
All the dilutes that I deal with in breeding are recessive, meaning that there needs to be two of them in the gentic code for the color to show.
Example:
This rat carries American Blue. Her genetic code is (aa Gg). The Black (aa) color shows, but the Blue (Gg) does not.
This rat shows American Blue. Her genetic code is (aa gg). The Blue gene (gg) diluted the Black gene (aa) and turned her coat American Blue.
When breeding rats, it's important to try and predict what colors will show in a litter. Punnet Squares make this easy.
Example:
To predict what the above rat would have in a litter, put the dilutes on each side of the square.
Then combine the letters on each side of the small squares and put them inside the square. 
Now when you read the inside of the small sqaures, you see pieces of genetic code.
These rat pups will be American Blue carriers:
These rat pups will show American Blue:
If both parent rats were American Blue carriers, the square would look like this:
These rats pups do not show or carry American Blue:
These rat pups carry American Blue:
These rat pups show American Blue:
Now, here is a list of dilutes and what they do by themselves. Note:Some colors have more than one recognized name. The ones I know are listed below. Underlined text is a link to a picture of the dilute.
The Base:
AA = Agouti colored (ticked fur)
Aa = Agouti colored (carries black)
aa = Black colored (solid colored fur)
Brown Dilute:
BB = No change in color
Bb = No Change in color (carries chocolate)
AA/bb = Chocolate Agouti or Cinnamon Agouti in color
aa/bb = Chocolate in color
Color Dilute:
CC = No change in color
Cc = No change in color (carries albino)
AA/cc = Albino (PEW) in color
aa/cc = Albino (PEW) in color
Dark Blue Dilute:
DD =
No change in color
Dd = No change in color (carries Russian Blue)
AA/dd = Russian Blue Agouti in color
aa/dd = Maltese or Russian Blue in color
Grey Dilute:
GG =
No change in color
Gg =
No change in color (carries American Blue)
AA/gg = Slate Blue Agouti, Blue Agouti, or Opal in color
aa/gg = Blue, English Blue, Slate Blue, or American Blue in color
Mink Dilute:
MM =
No change in color
Mm =
No change in color (carries Mink)
AA/mm = Cinnamon, American Cinnamon, or Mink Agouti in color
aa/mm = Mink in color
Pink Eyed Dilute:
PP =
No change in color
Pp =
No change in color (carries champagne)
AA/pp = Amber, Argente, Silver Fawn, or Pink Eyed Yellow in color
aa/pp = Champagne in color
Red Eyed Dilute:
RR =
No change in color
Rr =
No change in color (carries beige)
AA/rr = Fawn in color
aa/rr = Beige or Buff in color
Dilutes can also dilutes eachother to make even more interesting colors.
Agouti double dilutes:
AA/bb/dd: Linx, American Lynx, European Lynx, Classic Lynx, or Lilac Agouti.
AA/bb/gg: Light Blue Agouti or Opal
AA/bb/mm: Coffee Agouti
AA/bb/pp: Silver Fawn
AA/bb/rr: Topaz
AA/dd/gg: Double Blue Agouti
AA/dd/mm: Russian Mink Agouti
AA/dd/pp: Lemon Agouti, Black eyed Silver Agouti, Apricot, Apricot Agouti, or Blue Argente
AA/dd/rr: Russian Blue Fawn
AA/gg/mm: Blue Cinnamon
AA/gg/pp: Blue Amber or Silver Agouti
AA/gg/rr: Blue Fawn
AA/mm/pp: Unknown color
AA/mm/rr: Havana Agouti
Black double dilutes:
aa/bb/dd: European Lilac, Classic Lilac, Light Lavender, or Dove
aa/bb/gg: Platinum or Sky Blue Lavender
aa/bb/mm: Coffee
aa/bb/pp: Light Champagne
aa/bb/rr: Buff
aa/dd/gg: Double Blue, Russian Silver, Smoked Russian, or Silver Russian
aa/dd/mm: Dove, Russian Mink, or Black Eyed Platinum
aa/dd/pp: Russian Blue Champagne
aa/dd/rr: Blue Beige, Blue Buff, or Apricot
aa/gg/mm: Platinum
aa/gg/pp: Silver or Blue Champagne
aa/gg/rr: Platinum or American Blue Beige
aa/mm/pp: Unknown color
aa/mm/rr: Havana
As far as other factors go, there is the Dumbo gene, the Fuzzy Hairless gene, the Sphinx Hairless gene, the Rexing gene, and the tailless gene.
Dumbo is a recessive gene.
DuDu = No change (standard ear)
Dudu = No change (standard ear, dumbo carrier)
dudu = Dumbo ears
Fuzzy Hairless is a recessive gene.
FzFz = No change (standard coat)
Fzfz = No change (standard coat hairless carrier)
fzfz = Fuzzy Hairless coat
Sphinx Hairless is a recessive gene.
HrHr = No change (standard coat)
Hrhr = No change (standard coat hairless carrier)
hrhr = Hairless coat
Tailless is a recessive gene.
TalTal = No change (normal tail)
Taltal = No change (tailless carrier)
taltal = Tailless rat
The rexing gene is an interesting one. With this gene, carriers are also affected. This gene is dominant too, which makes it different from the earlier ones.
Example:
ReRe = Double Rex (This rat will look like a messy hairless rat. Hair will fall out and come back in periodically)
Rere = Rexed (Note the curly whiskers and curly fur of the rat in the picture.)
rere = No Change (Standard coat)
If you have any questions about genetics or this page, please Email me. If you can think of a way to simplify this page or make ti more easy to understand or if I have something wrong, please dro pme a line.
Copywritten, Little Footprints Rattery, 2006
