Whole genome scan in chickens for quantitative trait loci affecting carcass traits

An experiment was conducted to enable quantitative trait loci (QTL) mapping for carcass traits. The population consisted of 10 full-sib families origi nating from a cross between male and female founders chosen from two differ ent outcross broiler lines. Founder animals, parents, offspring, and grando ffspring are denoted as generation (G) 0, 1, 2, and 3 animals, respectively . Microsatellite marker genotypes were collected on G(1) and G(2) animals. Phenotypic observations were collected on G(3) animals. Recorded traits wer e BW at 48 d, carcass weight, carcass percentage, breast meat color, and le g score. Average adjusted progeny trait values were calculated for each G(2) animal and for each trait after adjusting phenotypic observations on G(3) animals for fixed effects, covariables, the additive genetic contribution of the ot her parent, and differences between sexes. The average adjusted progeny tra it values were used as the dependent variable in the QTL analysis. A QTL analysis was undertaken by modeling the segregation from G(1) to G(2) , using a full-sib across family regression interval mapping approach. In t otal, 27 autosomal Linkage groups covered with 420 markers were analyzed. G enomewise significance thresholds were derived using the permutation test a nd a Bonferroni correction. Two QTL, affecting two of the five analyzed tra its, exceeded suggestive linkage. The most significant QTL was located on C hromosome 1 at 466 cM and showed an effect on carcass percentage. The other QTL, which affected meat color, was located on Chromosome 2 and gave a pea k at 345 and 369 cM.