Mitf^tm1Arnh

This allele resulted from an unplanned intragenic duplication event that occurred during a targeted mutation of the gene. The targeted mutation was within exon 2B to change the coding sequence for amino acid 73 from serine to alanine (S73A) and a silent nucleotide change 10bp upstream to generate a diagnostic restriction site. A floxed neomycin selection cassette was also inserted into intron 2. During recombination, 85,222 bp of wild-type gene sequence duplicated and inserted after exon 4 so that 7 exons (1H through 4) are repeated. Restriction digest and Southern blotting confirmed the presence of the targeted mutation and the duplication event. (J:130168)