Genome-Wide QTL detection for growth, body composition and quality related traits in chicken
Résumé
During the past decades, genetic improvement for growth, body composition and quality related traits in chicken was obtained through a strong selection based on the phenotype. Since 20 years, the genetic variability has been studied through quantitative trait loci (QTL) detection in many different breeds or selected lines. This approach has led to the identifi cation of many QTLs but with localisation intervals too large to allow marker assisted selection. Since the sequencing of complete genomes, thousands of single nucleotide polymorphisms (SNPs) were identified. Therefore, regions unexplored before can be studied and QTL locations refi ned. The aim of this study was to fi ne map QTLs affecting 26 economically important traits by genotyping 1536 SNPs and 127 microsatellites on 579 F2 animals obtained by crossing divergently selected fat and lean lines. QTL interval mapping was performed with QTLMap software which was developed for populations containing a mixture of full and half-sib families. In addition to single QTL mapping, hypotheses such as the presence of two linked QTLs infl uencing the same trait were tested. A total of 57 QTLs was detected at the 5% chromosome wide level and 28 QTLs were suggested at the 10% chromosome wide level. A further list of 13 QTLs was detected by multi-QTL approach. Our results confi rmed some QTLs previously identifi ed with the set of microsatellite markers and refi ned their position. Interestingly, additional QTLs were identifi ed mostly because this study provided a better coverage of the chicken genome (28 chromosomes), including chromosomal regions which had never been thoroughly studied.