Fine-mapping quantitative trait loci for body weight and abdominal fat traits: effects of marker density and sample size.

Highly significant QTL for BW and abdominal fat traits on chicken chromosome 1 were reported previously in a unique F2 population. The objective of this study was to confirm and refine the QTL locations. Compared with the previous experiment, this study added 8 new families, including all the animals in the pedigree, and genotyped 9 more microsatellite markers, including 6 novel ones. Linkage analyses were performed. The results of the linkage analyses showed that the confidence intervals for BW and abdominal fat percentage were narrowed sharply to a small interval spanning 5.5 and 3.7 Mb, respectively. The results of the present study showed that using more markers and individuals could decrease the confidence interval of QTL effectively. In the current QTL region, by combining the biological knowledge of genes and the results of a microarray analysis that was performed in divergently selected lean and fat lines, several genes stood out as potential candidate genes.