Establishment of consomic mice to clarify host susceptibility to caries

Our previous study showed that inbred mice strains such as C57BL/6CrSlc (B6) and C3H/HeSlc (C3H) revealed high and low caries susceptibility, respectively. Quantitative trait locus (QTL) analysis was performed by a genome-wide scan on genetic crosses of B6 and C3H mice. The analysis showed that two effective values, one significant QTL was found on chromosome2, and the other suggestive QTL was detected on chromosome8. For the elucidation of the causative genes of dental caries susceptibility, we constructed mice termed consomic mice (B6-Chr.2C3H), in which the chromosome2 derived from B6 was replaced by that of C3H. For establishment of consomic mice, 2nd generation mice were obtained by mating B6 and F1 (B6×C3H). Microsatellite markers were used during confirmation of the genomic recombination. The recombination mice showing heterozygous genotype on the whole chromosome2 were crossed to the next generation continuously. Until the 13th generation, the mice were continuously genetically crossed by backcross and the genotype of all chromosomes was checked. The selected mice of the 13th generation were checked for heterozygous genotype of B6 and C3H on chromosome2, and whether all were homozygous for B6 on all chromosomes except chromosome2 and finally B6-Chr.2C3H were established by intercrossing the selected mice of 13th generation. We established consomic mice that can be used as an experimental model for investigating the causative genes of dental caries susceptibility.