Quantitative trait loci for periosteal circumference (PC): identification of single loci and epistatic effects in F2 MRL/SJL mice.

To test the hypothesis that periosteal circumference (PC), which is associated with bone size through cross-sectional moment of inertia (CMI), has heritable components, we performed a linkage analysis using 633 MRL/SJL F(2) mice that have 14% difference in mean PC. PC was determined in femurs by use of peripheral quantitative computerized tomography (pQCT). The genome-wide scan identified nine QTL for PC adjusted by body weight on chromosomes 1 (2 QTL), 2 (2 QTL), 8, 11, 15, 17, and X, which accounted for 38.

Quantitative trait loci (QTL) for lean body mass and body length in MRL/MPJ and SJL/J F(2) mice.

Studies on the genetic mechanisms involved in the regulation of lean body mass (LBM) in mammals are minimal, although LBM is associated with a competent immune system and an overall good (healthy) body functional status. In this study, we performed a high-density genome-wide scan using 633 (MRL/MPJ x SJL/J) F(2) intercross to identify the quantitative trait loci (QTL) involved in the regulation of LBM. We hypothesized that additional QTL can be identified using a different mouse cross (MRL/SJL cross).

Genetic variation in bone-regenerative capacity among inbred strains of mice.

Genetic variation in bone-regenerative capacity has not been studied in any animal model system. We developed a "drill-hole" model in the tail vertebra of inbred strains of mice that allows us to reproducibly introduce an injury with a defined boundary and quantify the rate of bone healing using the combination of high-resolution Faxitron X-ray imaging and the ChemiImager 4000 Low Light Imaging System. Using this model, we demonstrate that bone-regenerative capacity is a genetically controlled trait with an estimated heritability of 72%, and that it differs significantly among inbred strains of mice.