Detection of QTLs controlling fatness traits in chickens using DNA fingerprint markers

Genetic linkage analyses were carried out on a large sib-ship of back-cross chickens for identifying major Quantitative trait loci (QTL) influencing various body fatness indicators and broiler traits, using multi-locus DNA fingerprints through novel statistical approaches. DNA fingerprints (DFP) generated by multi-locus VNTR probe: R18.1 and restriction enzyme AluI were used. The DFP marker - quantitative trait linkage analysis was accomplished via two sequential steps i.e. Tail analysis and the DFP band frequency - phenotypic trait-mean correlation analysis for pools identified across the phenotypic distribution. Tail analysis (TA) revealed that 12 DFP bands of sizes ranging from 3.5 Kb to 24 Kb, were polymorphic between the tails, for percent abdominal fat and 10 number of DFP bands each, were identified from the TA of plasma triglyceride (TGL) and very low density lipoprotein (VLDL) concentration. Band-frequency analysis for TGL revealed significantly - high correlation [|r|≍ 0.99] (P< 0.01) for 2 DFP bands: sized 9.0 Kb and 6.4 Kb. Significant correlation of band frequency for these 2 DFP bands with TGL pool-means indicate a primary linkage between the DFP markers and the putative QTL governing TGL concentration in plasma.