A tamoxifen-inducible Flp recombinase was used to activate expression of Myo7a in Myo7a<sup>tm1a/tm1a</sup> homozygotes at 4 weeks old by excising the transcription disruption cassette in the tm1a allele allowing expression of the Myo7a gene, and ABRs were recorded before and after activation of the gene.<h4>Results</h4>Myo7a<sup>tm1a</sup> was found to be a recessive allele causing reduced transcription and early onset profound deafness. This evidence concerns the gene MYO7A and deafness.