Whole-Genome Scan for Linkage to Bone Strength and Structure in Inbred Fischer 344 and Lewis Rats

Authors

  • Imranul Alam,

    1. Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
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  • Qiwei Sun,

    1. Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
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  • Lixiang Liu,

    1. Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
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  • Daniel L Koller,

    1. Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
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  • Tonya Fishburn,

    1. Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
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  • Lucinda G Carr,

    1. Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
    2. Department of Pharmacology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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  • Michael J Econs,

    1. Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
    2. Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
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  • Tatiana Foroud,

    1. Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
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  • Charles H Turner PhD

    Corresponding author
    1. Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
    2. Biomechanics and Biomaterials Research Center, Indiana University School of Medicine, Indianapolis, Indiana, USA
    • Department of Orthopaedic Research Indiana University School of Medicine 1120 South Drive, Fesler Hall 115 Indianapolis, IN 46202, USA
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  • The authors have no conflict of interest.

Abstract

A genome-wide genetic linkage analysis identified several chromosomal regions influencing bone strength and structure in F2 progeny of Fischer 344 x Lewis inbred rats.

Introduction: Inbred Fischer 344 (F344) and Lewis (LEW) rats are similar in body size, but the F344 rats have significantly lower BMD and biomechanical strength of the femur and spine compared with LEW rats. The goal of this study was to identify quantitative trait loci (QTL) linked to bone strength and structure in adult female F2 rats from F344 and LEW progenitors.

Materials and Methods: The 595 F2 progeny from F344 x LEW rats were phenotyped for measures of bone strength (ultimate force {Fu}; energy to break {U}; stiffness {S}) of the femur and lumbar vertebra and structure (femur midshaft polar moment of inertia {Ip}; femur midshaft cortical area; vertebral area). A genome-wide scan was completed in the F2 rats using 118 microsatellite markers at an average interval of 20 cM. Multipoint quantitative linkage analysis was performed to identify chromosomal regions that harbor QTL for bone strength and structure phenotypes.

Results: Evidence of linkage for femur and lumbar strength was observed on chromosomes (Chrs) 1, 2, 5, 10, and 19. Significant linkage for femoral structure was detected on Chrs 2, 4, 5, 7, and 15. QTLs affecting femoral strength on Chrs 2 and 5 were also found to influence femur structure. Unique QTLs on Chrs 1, 10, and 19 were found that contributed to variability in bone strength but had no significant effect on structure. Also, unique QTLs were observed on Chrs 4, 7, and 15 that affected only bone structure without any effect on biomechanics.

Conclusion: We showed multiple genetic loci influencing bone strength and structure in F344 x LEW F2 rats. Some of these loci are homologous to mouse and human chromosomes previously linked to related bone phenotypes.

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