International Mammalian Genome Society


The 13th International Mouse Genome Conference
October 31-November 3, 1999

Table of Contents * Structure * Bioinformatics * Sequence * Mapping * New Tools * Gene Discovery * Developmental * Mutagenesis * Functional Genomics

F41 Characterization of the Deaf Mouse Mutant, jackson circler (jc)

Michelle L. Mack*1 and Konrad Noben-Trauth1. *Graduate Program in Genetics, George Washington University, Washington, D.C.; 1Section on Murine Genetics, Laboratory of Molecular Genetics, National Institute on Deafness and Other Communicative Disorders, National Institute of Health, Rockville, MD 20850

The jackson circler (jc) mouse mutation arose spontaneously on the C57BL/6J background and results in deafness, erratic circling behavior, and head bobbing indicative of an inner ear defect. Auditory evoked brainstem response (ABR) analyses of 3-6 week old jc/jc homozygotes (n=11) resulted in 64% of animals (n=7) with no response to a wide range of acoustic stimuli (click, 8, 16, and 32 kHz) at varying sound pressure levels (20-100 dB SPL) and 36% (n=4) with statistically elevated click thresholds (>85 dB SPL). To examine the pathological basis of the jc phenotype, we studied whole mount preparations of methyl salicylate cleared inner ears (n=10) and found that jc/jc homozygotes lack the apical turn of the cochlea. To our knowledge, there are no other spontaneous mouse mutations resulting in a similar cochlear malformation.

Genetic mapping studies by Southard et al. (1970) placed jc on mouse chromosome 10 at 28.5 cM+/- 3 cM. To refine the location of jc, we have generated approximately 1400 meioses from an intersubspecific intercross using the C57BL/6J-jc and CZECH/IIei strains. Our results have defined the jc interval as a 0.9 cM region on mouse chromosome 10 (25.5 cM) between D10Mit108 and D10Mit55. We are currently isolating BACs to assemble a physical contig encompassing the 0.9 cM interval. In addition, we are radiation hybrid mapping identified ESTs from these BACs and the human syntenic region 6q21 to evaluate their potential as candidate genes. We postulate that the gene responsible for jc is critical in cochlear development and/or cochlear pattern formation.

Southard JL. Jackson circler, jc. Mouse News Letters 1970; 42:30.

 


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