IDENTIFICATION OF THE OIM MUTATION BY DYE TERMINATOR CHEMISTRY COMBINED WITH AUTOMATED DIRECT DNA-SEQUENCING

The homozygous oim/oim mouse, a model of moderate-to-severe human oste ogenesis imperfecta, contains a G-nucleotide deletion in the Cola-2 ge ne (the murine pro alpha 2(I) collagen gene) that results in accumulat ion of alpha 1(I) homotrimer collagen. Although these mice have a dist inctive phenotype that includes multiple fractures and deformities, ge notyping is necessary to distinguish them from their wildtype (+/+) an d heterozygote (oim/+) littermates. In this study, the dye primer and dye terminator chemistry methods, in combination with automated direct DNA sequencing, were compared for accuracy and ease in genotyping. A total of 82 mice from 14 litters were bred and genotyped; this resulte d in 18 +/+, 35 oim/+, and 29 oim/oim mice. The dye primer and dye ter minator chemistry methods worked equally well for identification of th e deletion mutation and thus the genotype of all of the mice. However, the dye terminator method was found to be superior on the basis of th e reduced amount of sample handling and reduced quantity of reagent re quired.