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). Ten QTL were identified for LBM on chromosomes (chrs) 2, 6, 7, 9,13 and 14. Of those ten, QTL on chrs 6, 7 and 14 were exclusive to LBM, while QTL on chrs 4 and 11 were exclusively body length. LBM QTL on chrs 2 and 9 overlap with those of size. Altogether, the ten LBM QTL explained 41.2% of phenotypic variance in F(2) mice. Five significantly interacting loci that may be involved in the regulation of LBM were identified and accounted for 24.4% of phenotypic variance explained by the QTL. Five epistatic interactions, contributing 22.9% of phenotypic variance, were identified for body length. Interacting loci on chr 2 may influence LBM by regulating body length. Therefore, epistatic interactions as well as single QTL effects play an important role in the regulation of LBM.
Molecular Genetics Division, Musculoskeletal Disease Center, J.L. Pettis VA Medical Center and Loma Linda University, 11201 Benton Street (151), CA 92357, USA.
Godfred L
GL
Masinde
Xinmin
X
Li
Weikuan
W
Gu
Heather
H
Davidson
Melanie
M
Hamilton-Ulland
Jon
J
Wergedal
Subburaman
S
Mohan
David J
DJ
Baylink
D000483:Alleles; D000818:Animals; D001824:Body Constitution; D001835:Body Weight; D004843:Epistasis, Genetic; D005260:Female; D005838:Genotype; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010641:Phenotype; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable