RT-PCR and immunohistochemical analysis indicates greatly reduced mRNA expression and absence of protein expression in homozygous mice. However, no mutations in Myo6 exon sequence, exon-intron boundaries or promoter region are detected. An alternative splice variant of Myo6 is found in both rsv mice and wild-type mice. The non-recombinant region spans from D9Mit74 to D9Nok18. (J:261136)