American Fancy Rat & Mouse Association

This article is from the Nov/Dec 1996 AFRMA Rat & Mouse Tales news-magazine.

Rat Genetics, part 3

By Nichole Royer


Listed below are the known or suspected genotypes of colors currently recognized or being bred by AFRMA members. Whenever possible, I have used the traditional “scientifically assigned” symbol for the genes; however, there are a few instances where one does not currently exist, so I made one up. These are denoted with a (*). There are also some cases where the colors are new or their genetic background is somewhat uncertain, and these are denoted by (?). If anyone has definite evidence of these animal’s genetic make-up, please let me know. Dashes (-) mean that either the dominant or recessive allele could occupy that space without affecting the outcome.


Agouti Group
Silver FawnA-B-C-D-G-M-ppR-
(selected for lighter color)
[Note: can also be A-B-C-D-G-mm-ppR-]
Blue AgoutiA-B-C-D-gg M-P-R-
LynxA-B-Ccch D-G-M- P-R-,
A-B-C-D-G-mm P-rr,
A-B-C-D-L-mm ppR, or ???
ChinchillaA-B-cchcchD-G-M-P-R- ?
(Formerly called Silver Agouti)
CinnamonA-B-C-D-G-mm P-R-
Cinnamon PearlA-B-C-D-G-mm Pe-P-R-
Black Group
Blackaa B-C-D-G-M-P-R-
Beigeaa B-C-D-G-M-P-rr
Champagneaa B-C-D-G-M-ppR-
Chocolateaa bb C-D-G-M-P-R-
Pale Champagneaa bb C-D-G-M-pp R-
Blue Group
Blueaa B-C-D-gg M-P-R- *
(selected for dark shade)
Sky Blueaa B-C-D-gg M-P-R- *
(selected for medium shade)
Powder Blueaa B-C-D-gg M-P-R- *
(selected for lightest shade)
Silveraa B-C-D-gg M-pp R- *
Platinumaa bbC-D-gg M-P-R- ? *
Russian Blue Group
Russian Blueaa B-C-dd G-M-P-R-
Blue-Beigea B-C-dd G-M-P-rr ?
(selected for medium shade)
Silver Platinumaa bb C-dd G-M-P-R- ?
Silver Blueaa B-C-dd gg M-P-R- or
aa B-C-D-gg mm -R ? *
Siamese Group
Seal Point Siameseaa B-chch D-G-M-P-R-
Blue Point Siameseaa B-chch D-gg M-P-R- *
Russian Blue Point Siameseaa B-chch dd G-M-P-R-
Himalayanaa B-chc D-G-M-P-R-
Pink-eyed White (albino)any cc any
Pearl, Mink/Lilac, Merle Group
Pearlaa B-C-D-G-mm Pepe P-R-
(selected for most of the hair shaft to be white)
Silver Minkaa B-C-D-G-mm Pepe P-R-
(selected for colored hair shaft and darker color)
Silver Lilacaa B-C-D-G-mm Pepe P-R-
(selected for colored hair shafts and lighter color)
Minkaa B-C-D-G-mm pepe P-R-
(selected for darker color)
Lilacaa B-C-D-G-mm pepe P-R-
(selected for lighter color)
Pale Champagneaa B-C-D-G-mm pp R-
Dark-eyed Champagneaa B-C-D-G-mm P-rr
Pearl Merleaa B-C-D-G-mm Me-Pepe P-R- *
(selected for most of the hair shaft to be white)
Silver Mink/Lilac Merleaa B-C-D-G-mm Me-Pepe P-R- *
(selected for colored hair shafts)
Mink/Lilac Merleaa B-C-D-G-mm Me-pepe P-R- *
Silver Blackaa B-C-D-G-M-P-R-
(selected for silvering)
Silver Chocolateaa bb C-D-G-M-P-R-
(Selected for silvering)
Silver AgoutiA-B-C-D-G-M-P-R-
(selected for silvering)
(Not recognized by AFRMA)


  • “Genetics of Fancy Rats” by Ann Storey, Pro-Rat-A, The National Fancy Rat Society Journal, November/December 1995, Number 90, pp. 7–11 (This is the most current and up-to-date information available on the genetics of fancy rats. She includes much more information than I have been able to present and I highly recommend anyone interested in this subject get a copy. There will be a more detailed version of this article appearing in the next NFRS Handbook which will be out in 1997. I am anxiously awaiting its publication.)
  • “Genetics” by Ann Storey, National Fancy Rat Society Handbook, a Pro-Rat-A publication 1991, pp. 30–35. (Also published in various issues of Pro-Rat-A and AFRMA Rat and Mouse Tales, this article was the old standby for genetics information. It contains most of the basics and is well worth reading.)
  • The Proper Care of Fancy Rats by Nick Mays, T.F.H. publications, Inc., 1993 pp. 226–53. (Contains an excellent section on how genetics work and is a must read for anyone just being introduced to the world of genetics.)
  • “Genetics for Mouse Breeders” series by Bonnie Walters, published in various issues of AFRMA Rat and Mouse Tales. (If you ignore the fact that it is talking about mice, this is the best information on how genetics work that is available. This series of articles contains the most complete and detailed explanations of the workings of genetics, how and why breedings produce what they do, and what to expect when crossing one thing to another. If you ignore the information on color genetics, which are different for mice than they are for rats, it’s a very valuable resource.)
  • The Inheritance of Coat Color in Dogs by Clarence C. Little, Sc. D., Howell Book House 1971. *
AFRMA/NFRS Translations

(For people like me who are easily confused)

Blue AgoutiOpal? or Blue Agouti
Silver Agouti/ChinchillaChinchilla
LilacLight Mink
Sky BlueBlue
AmberLight Silver Fawn
Blaze BerkshireBadger
English IrishIrish
Lightly Marked BerkshireBerkshire
IrishLightly Marked Berkshire

Go to Rat Genetics, part 1
Go to Rat Genetics, part 2
Go to Rat Genetics - The WHAT IF chart

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Updated December 10, 2018