Strain Name:
Variable White
Stock Number:
Citation ID:
Major Collection:

Gene Information

Genotype Determination
Considerable variation occurs among individuals in the extent of unpigmented pelage. There is extensive white on the face, ears and forehead. The tail is largely unpigmented in most individuals, and invariably is white at the tip. In the unpigmented areas the individual hairs are white throughout. The mid-dorsum is nearly always pigmented, but not clearly delineated. The margins of the pigmented areas appear ragged and uneven. Furthermore, the pigment is less intense or more diluted than in wild-type hairs, giving the pigmented regions a grayish-tan wash. The eyes appear dark like those of the wild-type. Microscopic analysis of fixed, paraffin embedded, stained sections of skin revealed an absence of unpigmented melanocytes (clear cells) in hair follicles from the white areas of the skin, while pigmented melanocytes were present in the pigmented portions of the pelage. A noticeable feature of the mutant phenotype is variability in response to auditory stimuli. Some individuals appear to be deaf, while others react normally. Auditory deficiency was more pronounced in the males tested. In general, animals withe high expression of white on the head were more likely to exhibit deafness, indicative of a basic defect in neural crest cell migration. Female variable white usually do not bear viable young. Variable white deer mice are unable to swim.
Strain Development
Source: The first variable white mutant animal appeared spontaneously in 1983 in a long-established stock of wild-type prairie deer mice, P. m. bairdii, maintained at Michigan State University. A mated pair which had previously yielded more than 50 wild-type progeny produced a single female exhibiting the variable white phenotype.
Primary Reference

For more information, please see Variable White on the Peromyscus Genetic Stock Center website.

Colony and Husbandry Information

Colony Surveillance Program and Current Health Reports

For more information about this colony's health status contact
Coat Color
Homozygous (Vw/Vw) There is extensive white on the face and forehead. The tail is largely unpigmented.

Heterozygous (Vw/+) coat color has more variable white than the wild-type

MMRRC Breeding System
Not applicable; only cryopreserved sperm is available. The parent colony was sufficiently large to use a random breeding scheme
Breeding Scheme(s)
Not applicable; only cryopreserved sperm is available; mice cryorecovered (see below) can be bred Wild-type female x Wild-type male
Overall Breeding Performance
Peromyscus mice breed best using a 16:8 light / dark cycle. Female Variable White usually do not bear viable young.
Average litter size
Recommended wean age
25 days

Order Request Information

Male mice were obtained from the Peromyscus Genetic Stock Center as part of a long term project to develop cropreservation techniques for Peromyscus. Sperm have been cryopreserved and are available. However, cryorecovery techniques have yet to be developed.

Distribution of this strain requires submission of the MMRRC Conditions of Use (COU). A link to the COU web form will be provided via email after an order has been placed; the form should be completed then or the email forwarded to your institutional official for completion.

- Products for this strain are Not Yet Available for Ordering
- If you register interest in this strain, you will be notified when it becomes available for ordering.

To request material from the MMRRC: Please fill out our on-line request form (accessible from the catalog search results page, or click the Request this Strain button in the fees section). If you have questions or need assistance completing this form, you may call Customer Service at (800) 910-2291 (in USA or Canada) or (530) 757-5710 (international calls). Before you call, please have with you: the MMRRC item number, quantity needed, Bill-to and Ship-to contact information.