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Title:QTL Mapping and Molecular Dissection of Meat Quality Traits in Swine
Author(s):Meyers, Stacey N.
Doctoral Committee Chair(s):Beever, Jonathan E.
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Agriculture, Animal Culture and Nutrition
Abstract:Improvement of meat quality is important for consumer satisfaction. As many pork quality traits cannot be assessed in the live animal, selection for these traits must rely upon genetic determinants known as quantitative trait loci (QTL). To facilitate fine-mapping of swine QTL, a ∼1 Mb-resolution human-pig comparative map, composed of 2,274 markers in 34 linkage groups, was constructed using the radiation hybrid method. Comparative analyses revealed 51 conserved synteny groups, including 173 conserved segments, and overall comparative coverage greater than 90%. This map was used, together with porcine linkage and bacterial artificial chromosome (BAC) physical maps, to fine-map a QTL affecting pork tenderness that was detected, on the q arm of porcine chromosome 2 (SSC2q), within the Illinois Meat Quality Pedigree (IMQP). Nine novel microsatellite markers within the ∼30-Mb region surrounding the most likely QTL position, including one within the candidate gene calpastatin (CAST), were developed. These markers, along with nine publicly-available markers, were used to perform linkage and haplotype analyses within the IMQP. Within-family linkage analyses revealed at least two families segregating for a highly-significant QTL in strong positional agreement with CAST. A combined analysis of these two families yielded QTL intervals of 36 cM and 7 cM for Instron shear force and taste panel tenderness, respectively, while haplotype analyses suggested further refinement to a 1.8 cM interval containing CAST. To identify allelic variation that may influence pork tenderness, the complete genomic sequence of porcine CAST was determined. Nearly 77.6% of this gene was then re-sequenced from each of six IMQP F1 boars. Based on heterozygosity, 393 of 896 discovered polymorphisms appeared concordant with previous QTL data. The location of this variation within the CAST gene suggests that a causative mutation is likely to be regulatory. Functional characterization of CAST variation should enhance understanding of the molecular basis of pork tenderness, and thus allow for genetic improvement of pork products. The effectiveness of CAST polymorphisms for marker-assisted selection (MAS) of pork tenderness can now be assessed. Furthermore, genomic resources developed in this study may be used to investigate many other porcine QTL, including additional tenderness QTL suggested on SSC2q.
Issue Date:2007
Description:134 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.
Other Identifier(s):(MiAaPQ)AAI3301269
Date Available in IDEALS:2015-09-25
Date Deposited:2007

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