1. Bone. 2008 Mar;42(3):547-53. Epub 2007 Nov 28.
Genetic loci affecting bone structure and strength in inbred COP and DA rats.
Sun Q(1), Alam I, Liu L, Koller DL, Carr LG, Econs MJ, Foroud T, Turner CH.
Author information:
(1)Department of Biomedical Engineering, Indiana University School of Medicine,
Indianapolis, IN 46202, USA.
Previous studies have shown that the Copenhagen 2331 (COP) and Dark Agouti (DA)
rats have significant differences in bone structure and strength despite their
similar body mass. Thus, these inbred rat strains may provide a unique resource
to identify the genetics underlying the phenotypic variation in bone fragility. A
sample of 828 (405 males and 423 females) COPxDA F2 progeny had extensive
phenotyping for bone structure measures including cortical bone area and polar
moment of inertia at the femur midshaft and total, cortical and trabecular bone
areas, for the lumbar vertebra 5 (L5). Bone strength phenotypes included ultimate
force, stiffness and work to failure of femur and L5. These skeletal phenotypes
were measured using peripheral quantitative computed tomography (pQCT) and
mechanical testing. A whole-genome screen was conducted in the F2 rats, using
microsatellite markers spaced at approximately 20 cM intervals. Genetic marker
maps were generated from the F2 data and used for genome-wide linkage analyses to
detect linkage to the bone structure and strength phenotypes. Permutation testing
was employed to obtain the thresholds for genome-wide significance (p<0.01).
Significant QTL for femur structure and strength were identified on chromosome
(Chr) 1 with a maximum LOD score of 33.5; evidence of linkage was found in both
the male and female rats. In addition, Chrs 6, 7, 10, 13, 15 and 18 were linked
to femur midshaft structure. QTL linked to femur strength were identified on Chrs
5 and 10. For L5 vertebrae, Chrs 2, 16, and 18 harbored QTL for cortical
structure and trabecular structure for L5 was linked to Chrs 1, 7, 12, and 18.
One female-specific QTL for femur ultimate force was identified on Chr 5, and two
male-specific QTL for L5 cortical area were found on Chrs 2 and 18. Our study
demonstrates strong evidence of linkage for bone structure and strength to
multiple rat chromosomes.
PMCID: PMC2288735
PMID: 18158281 [PubMed - indexed for MEDLINE]
PUBMED: 18158281
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