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Genetic mapping of the whirler mutation
M J Rogers1, J Fleming, B W Kiernan
1MRC Institute of Hearing Research, University Park, Nottingham, UK.
Summary
The whirler (wi) mutation causes deafness and balance problems in mice. Genetic mapping precisely located the wi mutation on mouse Chromosome 4, aiding future research into hearing and vestibular disorders.
Area of Science:
- Genetics
- Neuroscience
- Developmental Biology
Background:
- The whirler (wi) mutation in mice causes autosomal recessive neuroepithelial deafness and vestibular dysfunction.
- Affected mice exhibit characteristic "shaker-waltzer" behaviors, including deafness, circling, and head-bobbing.
Purpose of the Study:
- To construct a high-resolution genetic linkage map around the whirler (wi) locus on mouse Chromosome 4.
- To precisely map the genetic location of the wi mutation using both interspecific and intraspecific backcrosses.
Main Methods:
- Genetic linkage mapping was performed using two backcross populations: an interspecific [(wi/wi x CAST/Ei)F1 x wi/wi] (n=817) and an intraspecific [(wi/wi x CBA/Ca)F1 x wi/wi] (n=335).
- Analysis involved identifying non-recombinant markers and calculating genetic distances (centimorgans, cM) to pinpoint the wi locus.
Main Results:
- In the interspecific backcross, wi was non-recombinant with Orm1, located 0.12 cM distal to D4Mit87 and Ambp, and 0.12 cM proximal to CD301.
- In the intraspecific backcross, wi was non-recombinant with Orm1 and D4Mit244, situated 0.3 cM distal to Mup1 and 0.6 cM proximal to Tnc.
- A specific family within the interspecific backcross displayed evidence of multiple recombinations in the vicinity of the wi locus.
Conclusions:
- The genetic mapping has refined the location of the whirler (wi) mutation on mouse Chromosome 4.
- The identified genetic markers provide valuable tools for further investigation into the molecular basis of deafness and vestibular dysfunction associated with the wi mutation.