The use of genetic markers to identify regions of the genome associated with variation in quantitative traits (QTL) is now widespread. Several studies have attempted to find QTLs for growth and fatness in pigs. Since the first published study (Andersson et al., 1994) many groups have found effects on chromosome 4, albeit with different breeds. In theory, joint analysis offers considerable potential to extract additional information from the data. This study aims to investigate the benefits and drawbacks of joint analysis.
Data on birth weight (BWT), growth rate to end of test or slaughter (GRE) and average backfat depth (BF) were supplied from seven different pig populations in six countries. The data from Scotland, France, USA, Netherlands and half of the data from Germany were Meishan (MS) x commercial F2 populations. Data from Sweden and the remaining German data were from wild boar (WB) x commercial F2 populations. A total of 31 different markers were used, all on chromosome 4.