Dispersed white hair (Dwh): a new dominant mutation on Chromosome 2 affecting hair color
Dispersed white hair (Dwh): a new dominant mutation on Chromosome 2 affecting hair color
Louise Dionne, Patricia Ward-Bailey, Richard Samples, Kenneth R. Johnson, and Muriel Davisson
Source of Support:The research was supported by NIH/NCRR grant RR01183 to the Mouse Mutant Resources (M. T. Davisson PI) and Cancer Center Core Grant CA34196
Mutation (allele) symbol: Dwh
Mutation (allele) name: dispersed white hair
Gene symbol: Dwh
Strain of origin: B6C3Fe a/a-Large<myd>/J
Current strain name: B6.Cg-Dwh/J
Stock #: 006429 (View JAX®Mice Data Sheet for additional information including Price and Supply Information) Note: As of October 21,2008 available as Cryo only.
Phenotype categories: coat color
Abstract
A new spontaneous, dominant mutation affecting hair color patterning has been discovered and characterized in the Mouse Mutant Resource. The dispersed white hair (Dwh) mutation causes affected mice to have white hairs dispersed throughout the normally black coat and a concentrated patch of white located on the back or belly in variable locations.
Origin and Description
Mice carrying the Dwh mutation were discovered by Dr. Patsy Nishina in her research colony of B6C3Fe a/a-Large<myd>/J mice at the Jackson Laboratory in June of 2005. Heterozygous mice affected by this dominant mutation are recognized by white hairs (See Photo) and white spots (See Photo) which can be observed as soon as the first coat of hair comes in.
Genetic Analysis
Using our standard mapping protocols, two Dwh/+ females were mated to a CAST/Ei male. The offspring from these matings were backcrossed to C57BL/6J mice. The backcross generated 62 mice affected with the Dwh mutation that were utilized for linkage analysis. The Dwh mutation was determined to be on Chromosome 2 by linkage with D2Mit124. The Dwh mutation maps between D2Mit3 (NCBI 36 position 7.6 Mb) and D2Mit157 (NCBI 36 position 58.9 Mb). There is no recombination with the following nine Mit markers: D2Mit360, D2Mit6, D2Mit79, D2Mit295, D2Mit64, D2Mit7, D2Mit320, D2Mit322, and D2Mit72 which range from 14.6 Mb-49.1 Mb. This unusually large area lacking recombination may be due to a chromosome rearrangement, or perhaps the CAST/Ei mice used for the linkage cross may be causing recombination suppression.
Pathology
Hearing as assessed by auditory brainstem response (ABR) testing on three mutants at three weeks of age revealed no hearing loss.
The eyes of three mutants at 19 weeks of age were examined with an opthalmascope and determined to be normal.
A pathological screen of 2 mutants at 4 weeks of age and 1 mutant at 45 weeks of age revealed no gross abnormalities. Hair samples taken from a Dwh mutant were normal. All hair types (guard, awl, auchene, and zigzag)were present.
Acknowledgements
The authors wish to thank Chantal Longo-Guess for hearing assessment, Norm Hawes for the eye examinations, and Coleen Marden for excellent histopathological skills.
