Fine Mapping of Polymorphic Alcohol-Related Quantitative Trait Loci Candidate Genes Using Interval-Specific Congenic Recombinant Mice

Authors

  • Marissa A. Ehringer,

    1. Department of Pharmacology (MAE, JT, OC, FY, RH, JMS), Human Medical Genetics Program (MAE, JMS), University of Colorado Health Sciences Center, Denver, Colorado; and the Institute for Behavioral Genetics (BB, TEJ), University of Colorado, Boulder, Colorado.
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  • Jessica Thompson,

    1. Department of Pharmacology (MAE, JT, OC, FY, RH, JMS), Human Medical Genetics Program (MAE, JMS), University of Colorado Health Sciences Center, Denver, Colorado; and the Institute for Behavioral Genetics (BB, TEJ), University of Colorado, Boulder, Colorado.
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  • Otakuye Conroy,

    1. Department of Pharmacology (MAE, JT, OC, FY, RH, JMS), Human Medical Genetics Program (MAE, JMS), University of Colorado Health Sciences Center, Denver, Colorado; and the Institute for Behavioral Genetics (BB, TEJ), University of Colorado, Boulder, Colorado.
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  • Fan Yang,

    1. Department of Pharmacology (MAE, JT, OC, FY, RH, JMS), Human Medical Genetics Program (MAE, JMS), University of Colorado Health Sciences Center, Denver, Colorado; and the Institute for Behavioral Genetics (BB, TEJ), University of Colorado, Boulder, Colorado.
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  • Raquel Hink,

    1. Department of Pharmacology (MAE, JT, OC, FY, RH, JMS), Human Medical Genetics Program (MAE, JMS), University of Colorado Health Sciences Center, Denver, Colorado; and the Institute for Behavioral Genetics (BB, TEJ), University of Colorado, Boulder, Colorado.
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  • Beth Bennett,

    1. Department of Pharmacology (MAE, JT, OC, FY, RH, JMS), Human Medical Genetics Program (MAE, JMS), University of Colorado Health Sciences Center, Denver, Colorado; and the Institute for Behavioral Genetics (BB, TEJ), University of Colorado, Boulder, Colorado.
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  • Thomas E. Johnson,

    1. Department of Pharmacology (MAE, JT, OC, FY, RH, JMS), Human Medical Genetics Program (MAE, JMS), University of Colorado Health Sciences Center, Denver, Colorado; and the Institute for Behavioral Genetics (BB, TEJ), University of Colorado, Boulder, Colorado.
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  • James M. Sikela

    Corresponding author
    1. Department of Pharmacology (MAE, JT, OC, FY, RH, JMS), Human Medical Genetics Program (MAE, JMS), University of Colorado Health Sciences Center, Denver, Colorado; and the Institute for Behavioral Genetics (BB, TEJ), University of Colorado, Boulder, Colorado.
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  • Supported by Grants R01 AA11853 (JMS), R01 AA08940 (TEJ), R02 AA00195 (TEJ), MH16880–20 (MAE), and 5 P50 AA03527.

James M. Sikela, University of Colorado Health Sciences Center, Pharmacology Department, 4200 E. Ninth Ave. C236, Denver, CO 80262; Fax: 303–315–7097; E-mail: james.sikela@uchsc.edu.

Abstract

Background The inbred long-sleep (ILS) and inbred short-sleep (ISS) strains of mice are widely studied as a model of initial sensitivity to alcohol. Recently, a large comparative DNA sequencing study of candidate genes located within the four Lore quantitative trait loci (QTLs) associated with the ethanol-induced loss of righting reflex in ILS and ISS mice has identified eight genes that contain coding region differences corresponding to amino acid changes. Here, recently developed interval-specific congenic recombinant mice (ISCRs) have been used to map these genes in relationship to newly narrowed QTL regions.

Methods Regions of candidate genes containing DNA differences corresponding to previously identified amino acid changes between ISS and ILS mice were amplified from either genomic DNA or complementary DNA from ISCR mice using polymerase chain reaction. The products were purified and directly sequenced to determine the genotypes for each polymorphism. On the basis of these genotypic data, each candidate gene was determined to be located either within or outside of recently narrowed Lore QTL intervals.

Results Of these eight candidates with protein-coding differences, five are now excluded from their respective Lore intervals. The other three (Znf142, Ptprn, and Znf133) have been localized to the narrowed QTL intervals.

Conclusions These three central nervous system genes (Znf142, Ptprn, and Znf133) represent promising candidates for involvement in the differential sensitivity to alcohol exhibited between ILS and ISS mice. This study also demonstrates how the combination of high-throughput comparative gene sequencing and concomitant genetic fine mapping of QTL regions with ISCRs can be an effective tool for accelerating the process of moving from QTL to gene.

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