Genetic modulation of the iris transillumination defect: a systems genetics analysis using the expanded family of BXD glaucoma strains

Authors

  • Shankar Swaminathan,

    1. Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN, USA
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  • Hong Lu,

    1. Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN, USA
    2. The Affiliated Hospital of Nantong University, Nantong, China
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  • Robert W. Williams,

    1. Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
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  • Lu Lu,

    Corresponding author
    1. Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
    2. Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
    • Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN, USA
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  • Monica M. Jablonski

    Corresponding author
    • Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN, USA
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CORRESPONDENCE Monica M. Jablonski, e-mail: mjablonski@uthsc.edu or Lu Lu, e-mail: lulu521uthsc@gmail.com

Summary

We investigated the contributions of Tyrp1 and Gpnmb to the iris transillumination defect (TID) in five age cohorts of BXD mice. Using systems genetics, we also evaluated the role of other known pigmentation genes (PGs). Mapping studies indicate that Tyrp1 contributes to the phenotype at all ages, yet the TID maps to Gpnmb only in the oldest cohort. Composite interval mapping reveals secondary loci viz. Oca2, Myo5a, Prkcz, and Zbtb20 that modulate the phenotype in the age groups up to 10–13 months. The contributions of Tyrp1 and Gpnmb were highly significant in all age cohorts. Moreover, in young mice, all six gene candidates had substantial interactions in our model. Our model accounted for 71–88% of the explained variance of the TID phenotype across the age bins. These results demonstrate that along with Tyrp1 and Gpnmb, Oca2, Myo5a, Prkcz, and Zbtb20 modulate the TID in an age-dependent manner.

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