Combining QTL- and expression-analysis: identification of functional positional candidate genes for meat quality and carcass traits

In order to identify genes controlling meat quality and carcass traits we are aiming to combine two approaches: (1) the QTL analysis (2) and expression profiling. Here results of QTL analyses in different porcine resource populations and current attempts to identify functional candidate genes for meat quality traits are reviewed and own efforts are presented: A QTL scan for meat quality and carcass traits was conducted in two resource populations, the DUMI resource population based on Duroc and Berlin Miniature Pig and the DUPI resource population based on Duroc and Pietrain. This analysis provides positional information on QTL for these traits and confirms and supplements results of numerous other QTL scans. Differential display was used to compare transcription profiles of fetal (presumptive) M. longissimus dorsi tissue at 7 key stages of myogenesis in Pietrain and Duroc breeds. Furthermore differential display and microarray analyses were conducted of muscle and liver of discordant sibpairs with regard to body composition. Expression profiling offers a list of functional candidate genes for meat quality and carcass traits with trait-, breed-, and stage-associated expression of various physiological networks. The application of bioinformatic tools and the use and generation of mapping information of the differentially expressed genes combined with QTL information reveal segregating functional positional candidate genes. These will be selected for further association and molecular genetic analyses to provide statistical and functional evidence for their impact on meat quality and carcass traits and to elucidate prenatal events affecting postnatal growth performance and meat quality.