Quantitative trait locus analysis of gutter-shaped root(s) in C57L/J mouse

C57L/J mice have about 90–100% incidence of gutter-shaped root (GSR) on the lower second molars (M2). Many investigators have reported the morphological features of this anomaly, but the development mechanisms are not well-understood. A classic genetic study on the cause of GSR in C57L/J mice suggested that a genetic factor with autosomal-dominant inheritance affected the development of mouse GSR. The purpose of this study was to identify genome regions of mouse GSR with novel method. We used N2 backcross mice (N = 153) from C57L/J mice, AKR/J mice and 103 informative polymorphic Mit (Massachusetts Institute of Technology) markers in this study. To evaluate phenotype, we calculate Dental root fusion rate (D.R.F.R.) using micro-CT. Here, quantitative trait locus (QTL) analysis was used to detect the chromosomal regions responsible for the mouse GSR in C57L/J mice. Highly significant value was obtained in the approximately 5.5 cM area from D6Mit284 (30.6 cM) to D6Mit230 (36.1 cM) on chromosome 6, strongly suggesting the existence of a major gene associated with the components of gutter-shaped root.