Darkened dorsal; a new coat color mutation on Chromosome 2
Authors:Richard Samples, Patricia F. Ward-Bailey, Louise Dionne, and Kenneth R. Johnson
Source of Support: This research was supported by NIH/NCRR grant RR01183 to the Mouse Mutant Resource (M.T. Davisson, PI) and Cancer Center Core Grant CA34196
Mutation (allele) symbol: dkd
Mutation (allele) name: darkened dorsal
Gene symbol: a
Strain of origin: LPT/Le
Current strain name: LPT;C3-dkd/J
Stock #: 006058 (view JAX® Mice Data Sheet for additional information including Price and Supply Information)
Phenotype categories: skin and hair
Origin and Description
A new spontaneous recessive coat color mutation has been identified and named darkened dorsal (dkd). Mice carrying this mutation were discovered by Rebecca Rhodes in a colony of LPT/Le at the Jackson Laboratory. Mice homozygous for this mutation are identified by a darkened dorsal stripe that can be seen when the first coat of hair comes in. (See Photo) The LPT;C3-dkd/J colony is maintained by homozygous matings.
Genetic Analysis
Using our standard mapping protocols the dkd mutation was mapped to Chromosome 2. It maps between D2Mit260 (NCBI 36 position 149.0 Mb) and D2Mit148 (NCBI 36 position 178.5 MB) and is non-recombinant with D2Mit286 (NCBI 36 position 154.3Mb) and D2Mit196 (NCBI 36 position 160.2 Mb). Based on phenotype and chromosomal location, dkd is likely an allele of nonagouti (a) (NCBI 36 position 154.8 Mb).
Pathology
A pathological screen of two homozygous mutant mice was performed at 20 weeks of age and no gross abnormalities were observed.
Hearing as assessed by auditory brainstem response testing (ABR) of four homozygous mutants at four weeks of age was normal.
The eyes of four homozygous mutants at four weeks of age were examined with an opthalmoscope and were determined to be normal.
Acknowledgements
The authors thank Heping Yu for hearing assessment, Norm Hawes for eye examinations, and Coleen Marden for excellent pathological techniques.
