AbstractThe homozygousoimloimmouse, a model of moderate‐to‐severe human osteogenesis imperfecta, contains a G‐nucleotide deletion in the Cola‐2 gene (the murine proα2(I) collagen gene) that results in accumulation of α1(I) homotrimer collagen. Although these mice have a distinctive phenotype that includes multiple fractures and deformities, genotyping is necessary to distinguish them from their wildtype (+/+) and 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 resulted in 18 +/+, 35oim/+, and 29oim/oimmice. The dye primer and dye terminator chemistry methods worked equally well for identification of the 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 the reduced amount of sample handling and reduced quantity of reagent