American Fancy Rat & Mouse Association

This article is from the WSSF 2009 AFRMA Rat & Mouse Tales news-magazine.

Colors & Coats

Wants To Know More About Genetics/Genotypes of Mice; Genotypes of Wild Rodents

By Karen Robbins

Dave Howe, Beacon Falls, CT
QHello, my name is Dave Howe, I’m 24 years old, and I’ve been raising mice for years. I would love to get my hands on additional information on mice and their kin. I’ve only found one book that I got at my local pet store, entitled Mice—A Complete Pet Owner’s Manual, by Horst Bielfeld. It’s very informative, but I would like to know more about genetics! I would especially like to know if there is a genetic listing of all the known genotypes. Also, is there a list that tells which genes are dominant and which are recessive? I am also looking for information on the genotypes of all the relatives of mice, such as rats, hamsters, field mice, deer mice, wood mice, harvest mice, the European spiny mouse, and on possible hybrids, strange strains and mutations, and experimental lab mice. Thank you for your time and patience.

AThere are several web sites you can look into as well as doing a search on the Internet. We can give you sites for domestic rats and mice, but for the wild mice, you will have to do a search on the Internet.

The Whole Mouse Catalog has information on genetics. For Lab sources you can try the Mouse Genome Informatics (MGI) This provides integrated access to data on the genetics, genomics, and biology of the laboratory mouse. On the International Federation of Pigment Cell Societies web site “Color Genes” page, there is a table of color genes in mice

We have a link on our web site to a PDF article “The Color Loci of Mice—A Genetic Century.”

On the Jackson Laboratory web site they have several books online that would be of interest to you: The Coat Colors of Mice, A Model for Mammalian Gene Action and Interaction by Willys K. Silvers, published by Springer Verlag 1979 (; Mouse Genetics, Concepts and Applications by Lee M. Silver, published by Oxford University Press 1995 (, still available to purchase; Biology of the Laboratory Mouse, by The Staff of The Jackson Laboratory, Earl L. Green, Editor, Second Edition, Dover Publications, Inc., New York 1966, (, may still be able to find copies.

Another good site to check on domestic mice is the Finnish Show and Pet Mice genetics pages at

At this site (archived version), you will find “Ratmap: The Rat Genome Database.”

For basic genetics you can read the “Genetics Tutorial, Fancy Rat Genetics 101,” at (archived version)

And of course there are the AFRMA Mouse Genetics and AFRMA Rat Genetics books available from our web site or shows

The common way to determine dominant and recessive when looking at the genetic codes, is that dominant genes are in uppercase letters and recessive are in lowercase letters. For a mouse to show the recessive color, it has to be homozygous recessive or having both letters in the lowercase form.

In regards to hamsters there are a couple club sites we can refer you to: the California Hamster Association has genetics on Syrians, Campbells Dwarf, and Winter White Dwarf and the Midlands Hamster Club in the U.K. has Syrian genetics at The Purple Kat Kritters site has Syrian genetics at *

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June 27, 2014