International Conference on Animal Genetics 2006, Porto Seguro, Brazil
A QTL located on SSC2 and exhibiting large effects on both Instron shear force and taste panel tenderness was detected within the Illinois Meat Quality Pedigree (IMQP). Comparative analysis of SSC2 indicates that the QTL region is orthologous to a segment of HSA5 in which there appears to be only one major candidate gene, calpastatin (CAST). CAST polymorphisms have recently been shown to be associated with meat quality characteristics; however, for a number of reasons, the possible involvement of other genes and/or molecular variation in this region can not be excluded, thus requiring fine-mapping of the QTL. To initiate fine-mapping, a minimal tiling path (MTP) of regional BAC clones was selected using the high-resolution porcine WG-RH and BAC physical maps. Marker density within the ~30 Mb region surrounding the most likely QTL position was increased through the use of four publicly available microsatellites as well as 10 novel informative microsatellite markers, including two within the CAST gene, isolated from relatively evenly spaced MTP clones. Phenotypic and marker data were analyzed using the outbred F2 analysis servlet of QTL Express. In-depth analyses of individual half-sib families suggest the presence of two QTL within this region, each affecting both Instron shear force and taste panel tenderness. Further fine-mapping of the QTL interval will involve an iterative process of continued development and combined linkage/linkage disequilibrium analysis of new markers from MTP clones until maximal refinement has been achieved.