Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học quốc tế đề tài: Mapping Quantitative Trait Loci (QTL) in sheep. III. QTL for carcass composition traits derived from CT scans and aligned with a meta-assembly for sheep and cattle carcass QTL | Cavanagh et al. Genetics Selection Evolution 2010 42 36 http content 42 1 36 Ge n et i cs Selection Evolution RESEARCH Open Access Mapping Quantitative Trait Loci QTL in sheep. III. QTL for carcass composition traits derived from CT scans and aligned with a meta-assembly for sheep and cattle carcass QTL 1 1 1 1 1 Colin R Cavanagh Elisabeth Jonas Matthew Hobbs Peter C Thomson Imke Tammen Herman W Raadsma Abstract An Awassi X Merino X Merino single-sire backcross family with 165 male offspring was used to map quantitative trait loci QTL for body composition traits on a framework map of 189 microsatellite loci across all autosomes. Two cohorts were created from the experimental progeny to represent alternative maturity classes for body composition assessment. Animals were raised under paddock conditions prior to entering the feedlot for a 90-day fattening phase. Body composition traits were derived in vivo at the end of the experiment prior to slaughter at 2 cohort 1 and cohort 2 years of age using computed tomography. Image analysis was used to gain accurate predictions for 13 traits describing major fat depots lean muscle bone body proportions and body weight which were used for single- and two-QTL mapping analysis. Using a maximum-likelihood approach three highly significant LOD 3 15 significant LOD 2 and 11 suggestive QTL LOD 2 were detected on eleven chromosomes. Regression analysis confirmed 28 of these QTL and an additional 17 suggestive P and two significant P QTL were identified using this method. QTL with pleiotropic effects for two or more tissues were identified on chromosomes 1 6 10 14 16 and 23. No tissue-specific QTL were identified. A meta-assembly of ovine QTL for carcass traits from this study and public domain sources was performed and compared with a corresponding bovine meta-assembly. The assembly demonstrated QTL with effects on carcass composition in homologous regions on OAR1 2 6 and 21. Background Sheep
